Arctic weather outbreaks can inflict large loss of life and financial losses to the economy in the Central and Eastern U.S. Judah Cohen, climatologist at MIT, describes the influence of the Polar Vortex and Siberian snowpack on these weather patterns, as well as some insights on predicting their timing.

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Transcript:

00;00;01;18 - 00;00;27;02
Hal Needham
On the last episode of the GEO Track podcast, we heard the story behind Buffalo, New York's deadliest blizzard on record, the Christmas Week blizzard of 2022 inflicted 44 fatalities on a region normally accustomed to cold weather and heavy snow. In that podcast, meteorologist Don Paul talked about how changes in the polar vortex can lead to Arctic weather outbreaks in the United States and referenced the work done by Judith Cohen for understanding how these patterns work.

00;00;27;17 - 00;00;53;13
Hal Needham
Hey, everyone. I'm Dr. Hal, host of the GEO Track podcast. Welcome to GEO Track podcast number 64, which is a companion episode to the last one. In this episode, Judah Cohen comes on the podcast to explain the science behind extreme weather outbreaks in more detail. Dr. Cohen is a climatologist working at MIT in Boston. If you're new to the podcast, go track investigates the impact of extreme weather and natural disasters on individuals and communities.

00;00;54;01 - 00;01;14;14
Hal Needham
Our goal is to help you improve your decision making, risk assessment and communication related to extreme events so you can take action to make yourself, your family and your community more resilient. A quick favor to ask you. We would really appreciate if you would share this podcast with one person impacted by extremely cold temperatures. Could be a professional connection.

00;01;14;14 - 00;01;38;03
Hal Needham
Maybe someone that's an insurance professional who handles damage claims from frozen pipes, things like that. Or it could be your favorite. Ed, who loves gardening and is threatened by extreme cold in the winter with threats of freezing her garden outside her home. We wanted to focus again on Arctic weather outbreaks because this topic is so important as this phenomenon has inflicted catastrophic losses in recent years.

00;01;38;22 - 00;02;08;16
Hal Needham
Take the 2021 Texas freeze, for example. According to the Houston Chronicle, that event inflicted 246 fatalities, according to official official government records, and as many as 700 fatalities were including excess deaths, according to a study by BuzzFeed. The cost on the Texas economy was estimated at $130 billion. Again, this isn't a hurricane. This isn't a tornado outbreak. It's an extremely cold weather event that impacted Texas back in February of 2021.

00;02;09;09 - 00;02;32;25
Hal Needham
Researchers, practitioners, planners, insurance professionals, energy grid operators, landscapers, homeowners and many other people have wanted to know more about how these extreme cold weather outbreaks work so they can better mitigate against the impacts and better plan for their arrival. The search for these answers led us to Dr. Cohen, who will explain more of the big picture behind these extreme weather events and the science in their prediction.

00;02;33;07 - 00;03;05;18
Hal Needham
A more formal introduction of this week's guest, Dr. Judah Cohen is a visiting scientist at MIT Parsons Lab, which is part of the Civil and Environmental Engineering Department. His main position is director of seasonal forecasting at Air or atmospheric and environmental research. He's currently working on the impacts of snow, cover and sea ice variability on winter climate. He's also interested in accelerated Arctic warming and its influence on extreme mid-latitude weather and applying novel statistical techniques to sub seasonal and seasonal weather prediction.

00;03;06;07 - 00;03;33;24
Hal Needham
Another of his interest is researching decade old temperature trends and explaining these trends with large scale climate models. He received his Ph.D. from Columbia University and was also a postdoc at the NASSR. NASA's Goddard Institute for Space Studies. On Dr. Cohen's website, the banner reads Unique Winter Season Forecast based on Siberian snow cover. Most accurate model to date will unpack with all that means in this podcast episode with Dr. Judy Cohen.

00;03;34;14 - 00;03;37;13
Hal Needham
Judith, thank you so much for taking time to come on The Geographic podcast.

00;03;38;10 - 00;03;39;03
Judah Cohen
My pleasure.

00;03;39;20 - 00;03;48;24
Hal Needham
Judy. You've been researching Arctic outbreaks for a long time. I mean, what are you looking for in that type of research? What kind of relationship tips climatological are you looking for?

00;03;50;13 - 00;04;17;21
Judah Cohen
I don't know if I would describe it as Arctic outbreaks. I'm involved with the seasonal forecasting and I'm trying to make a seasonal forecast. So we're really more interested in will the winter be colder than normal, be modern normal travel and snowfall in there, though, That's really difficult. Sure. And I feel like that's more for entertainment purposes than the real rigorous science.

00;04;18;25 - 00;04;47;18
Judah Cohen
But obviously, you know, Arctic out, you know, one, two Arctic outbreaks of winter can make them, you know, make the difference in how the season, you know, averages come out. So, sure, I think, you know, in the winter of 20, 2021, we had that historic outbreak in February and that pretty much tilted, you know, what was previously up until then, a mild winter into a cold winter, at least for the central U.S..

00;04;48;02 - 00;05;12;20
Judah Cohen
So, I mean, and obviously there was a lot of impact to the energy infrastructure. And it's unfortunate, you know, because our casualties, fatalities. So, I mean, you know, so one Arctic outbreak can be very you know, can really be very important for the seasonal mean. Yeah.

00;05;12;26 - 00;05;34;09
Hal Needham
To I live in southeast Texas. We were highly impacted by that. We lost power for three or four days. And a lot of these homes are elevated without much insulation. So you could quickly get your home temperature down near or below freezing. Like you said, there were fatalities. So people now are really on edge. You know, they're wondering kind of looking over their shoulder and to our north saying, is something else like that coming, you know?

00;05;35;02 - 00;05;35;27
Judah Cohen
Right. Yeah.

00;05;36;17 - 00;05;49;10
Hal Needham
So what are some of the forcing mechanisms here? Like you talked about that February 2021 event. I mean, what really drives an event like that to push cold air that far south?

00;05;50;10 - 00;06;16;13
Judah Cohen
Yes. So I've been proposing this idea that well, I mean, I would say it has to do with the polar vortex. All right. I get much pushback. But, you know, maybe some people say I overemphasize the importance of the polar vortex. But I think it's very difficult to get severe winter weather without some kind of involvement in the polar vortex and the polar vortex.

00;06;17;06 - 00;06;35;08
Judah Cohen
Its normal state is is an area of low pressure that sits right on top of the North Pole. If you think of the atmosphere having two layers, you have a bottom layer is the troposphere. That's where we live, the weather curves, that's where the jet stream is that moved the weather systems that long. And then above that is that top layer of the stratosphere, and that's where the polar vortex is.

00;06;35;22 - 00;06;36;02
Hal Needham
Okay.

00;06;36;19 - 00;06;59;03
Judah Cohen
So as an area of low pressure sits right on top of the North Pole and like all areas of low pressure in the northern hemisphere, it has a circulation. This ribbon, a river around that that circulates from west to east. Sure. The polar vortex, you know, the configuration of it. The shape is very circular. And the coldest area of the northern hemisphere contained inside of that circulation, you know, on the Poleward side.

00;07;00;03 - 00;07;25;23
Judah Cohen
So it's nice circular shape. The cold air is is bottled up very close to the North Pole in the Times, though. And if you think of the I can give the analogy of the pole vortex as a spinning top, its normal status as fast spinning, you know, very quiet rotation and all the cold air is kept close to the center of rotation, but at times the polar vortex can become disrupted or weakened.

00;07;26;00 - 00;07;47;07
Judah Cohen
So it'd be like that top, you know, banging into something. And so that, you know, it starts to wobble, it slows down and it recites a wobble. Meander. And also, if you think of like an ice skater, an ice skate is a nice tight rotation. You know, had the arms close to the chest. It's, you know, the ice skater stumbles and arms for a flailing out.

00;07;47;26 - 00;07;57;29
Judah Cohen
Same with the cold air that's the size of the pole rises. It kind of extends out from the center rotation. So it will go much further south than normal. And then that's when we get these cold air outbreaks.

00;07;58;16 - 00;08;03;21
Hal Needham
When that happens is that called a weakening or is there an index with it? How do we refer to that.

00;08;03;21 - 00;08;22;24
Judah Cohen
Disruption of polar vortex disruption or weakening? So you have a strong and, you know, so people thought of the polar vortex kind of binary. It was strong and weak. So when it's strong, we tend to be mild. So late December or early January, the polar vortex got strong. We had mild weather before that. It was weakened. It disrupted.

00;08;22;24 - 00;08;31;08
Judah Cohen
We had that cold air outbreak there, you know, mid-to-late December. Now there are signs that the polar vortex is weakening again.

00;08;32;27 - 00;08;37;10
Hal Needham
So that could push more cold air down through southern Canada and into the continental U.S..

00;08;37;18 - 00;09;00;26
Judah Cohen
Yeah. Yes, I typically the cold here is the Rockies. The central U.S., I think seems to be the area that is most. Wow. So there are two flavors of main flavors. I'd say full vortex disruption. So the one is a very large one that is called sudden strikes rewarming, because there's a very dramatic warming in the over the North Pole in the stratosphere, polar stratosphere.

00;09;01;11 - 00;09;21;29
Judah Cohen
But the temperature rise within a week of over 100 degrees Fahrenheit. So that would not happen at the surface. That's the one that's been most studied. And the polar vortex when it gets is very large as far as we saw, just as warm as you could have, either a displacement with a polar vortex, you know, integrally whole begets moved quite a bit off the North Pole.

00;09;22;08 - 00;09;48;29
Judah Cohen
It can move. Typically it moves into the Eurasian continent. And there's also times where it kind of breaks into pieces. Okay, all the poverty explained, at least if you're looking at an animation, that's the most dramatic, that's the one that's been studied, I'd say like 99.9% of the scientific literature has been on these very large destruction. But then recently we're looking at this more minor disruption where the polar vortex kind of stretching out.

00;09;49;00 - 00;10;22;17
Judah Cohen
It elongates like pulling on a rubber band, right. So it's nice and circular. When it's done, it gets kind of pulled at pulling in two ends of a rubber band. And but what's important about these are the miners. I think people ignore them, but it turns out they had the biggest impact. You know, the severe winter weather is more in the US more closely associated with this polar vortex stretching than these much larger events that are called sudden strikes with warming and really the impacts of focus across Eurasia and not so much North America.

00;10;22;23 - 00;10;28;00
Hal Needham
So with the stretching, the elongation, that's where we could more often see some of this cold air coming down into.

00;10;28;14 - 00;10;49;09
Judah Cohen
Like February 2021, where they had that. Was it kind of this stretching of elongation this past December that was very severe in Buffalo. You guys got the worst of it. That was also a stretching event. It looks like another stretching event. This is coming up. You know, that is beginning now. It will kind of start to impact the weather at the end of the month.

00;10;49;17 - 00;10;57;25
Hal Needham
If you were to draw a map of these stretching events, is some of the territory still kind of circumnavigating the North Pole or.

00;10;57;25 - 00;11;23;09
Judah Cohen
Did so right? So if you think of the shape of the polar vortex, the circular, right. And in this the winds are circulating around it then are flows west to east, you know, across the US. So that means the source of the air is off the North Pacific, which is relatively mild compared to the continents. But what happens if it becomes stretch out is like this oblong, straight shape something.

00;11;23;25 - 00;11;43;08
Judah Cohen
Now the flow is not west east anymore, right? Because if you could try to picture as now north to south. Sure. Sure. So the source of our air changes, droughts, it's coming up the North Pacific. And that's why, you know, California right now is getting this firehose station. Sure. That that that the air is blowing in a straight line of the North Pacific.

00;11;43;08 - 00;12;02;01
Judah Cohen
And it just gets slammed with all this moisture. Yeah. But then, you know, as it comes down the Rockies, it warms up a lot. So we turn very mild. Sure. But now if you get this kind of elongated, oblong shape with the wind is not coming to the west, you know, from west, easiest line north to south. So it's pulling cold air out of Canada.

00;12;02;10 - 00;12;15;03
Judah Cohen
And even in the the most extreme event is bring air out of Siberia, which has the coldest air in the northern hemisphere. I think that's what happened in December, where it adapted to some Siberian air and that's why it was so extreme. You know, the cold so extreme.

00;12;15;12 - 00;12;33;06
Hal Needham
I used to live in Fairbanks, Alaska, and I was I noticed about a week before the really cold air hit the central and eastern U.S., the temperatures in Fairbanks, I mean, they were getting high temperatures, I think -36, things like that. I mean, it was really frigid up there. And I think moving, you know, to the south and east.

00;12;33;06 - 00;12;42;06
Judah Cohen
Yeah. So you would see you will see that, you know, ahead of these events, you'll see cold air start building up in the Alaskan northwest. And then, you know, it's kind of weird.

00;12;42;06 - 00;12;43;10
Hal Needham
Then it's on the move, right?

00;12;43;16 - 00;12;57;13
Judah Cohen
Yeah, that's right. Yes, that's typically right. Yeah. So the cold air doesn't disappear. It sends the kind of source of cool. Sure. You know, and then it gets pulled in an attempt and the kind of the jet stream pops into the southeast.

00;12;58;19 - 00;13;06;19
Hal Needham
Due to what models do you look at if you're trying to get an idea like, will there be another outbreak this winter? I mean, where do you look for that kind of information?

00;13;06;29 - 00;13;31;01
Judah Cohen
Well, now we have 11 miles, so every all the large countries have their own weather while they well, this event, U.S. weather model, there's a Canadian one, but the one that's considered the best in the world is the European one. Maybe you'll hear about it on the news like especially with hurricanes of choice. You know, the American Marshalls, this track for hurricane reporting shows that.

00;13;32;09 - 00;13;54;02
Judah Cohen
So, I mean, that's but that's good up to two weeks. And you know, if I'm in there good for a week. I mean, there's been tremendous advancement made there the models. But I do think they suffer from not coupling correctly what, you know, triggers these polar vortex disruptions and then once you get a polar vortex disruption, how does that translate into our weather?

00;13;54;25 - 00;14;17;11
Judah Cohen
So I do try to get ahead of the models in anticipating. So like for now, for example, so they're showing this polar vortex disruption where stretching could be more. But for now it's definitely a stretch. I'm not going to show I mean, I have to look this morning that was not, you know, relatively benign. I mean, it was you know, it's been pretty mild.

00;14;17;20 - 00;14;39;26
Judah Cohen
Also get close to seasonable. But I do think it's got super cold in Siberia. Sure. -80 degrees Fahrenheit. I mean, like really cold. You know, that cold we don't see even in Alaska, it doesn't get so I mean, I think there's so there's I mean, you know, when it gets really close to really I guess the first place you've got to look for for risk of really extreme cold is east Asia to China.

00;14;39;26 - 00;14;48;19
Judah Cohen
And I think they are predicting some severe winter weather there. But I think it's also, you know, could be for us as well. Typically it hits Asia first and then comes to us.

00;14;48;24 - 00;14;54;28
Hal Needham
So so you'll kind of look at East Asia, Siberia, China, Mongolia, and kind of see what's happening there, because their upstream here.

00;14;54;28 - 00;15;24;28
Judah Cohen
Is is the key. I mean, I you know, I said I like to say Siberia is the refrigerator of the northern hemisphere. Sure. So watch Siberia. So Siberia turned really cold in December. And I thought, okay, that's a nice like a read. That's a kind of warning warning shot that, you know, the Asia and U.S. where on the risk for extreme cold and that got really mild in December in Siberia amid the mid to late December is okay mild weather is coming and you know you know that works very well And then Siberia is turning much colder.

00;15;24;28 - 00;15;29;21
Judah Cohen
Now. However, this will, with severe returns called maybe two weeks later, turn turns called the here.

00;15;29;21 - 00;15;36;09
Hal Needham
So sure. So it's going to basically travel through Alaska, western Canada and then be on the move towards the central and eastern U.S..

00;15;36;24 - 00;15;52;24
Judah Cohen
Not all the time to get you know, the Siberian air gets tagged. It's called the Siberian Express here in the U.S. Sometimes I've heard they're sitting there and not always that happens. But I certainly think there's that at least some of that air could make its way, you know, probably in maybe early February.

00;15;53;22 - 00;16;01;29
Hal Needham
Do you do you see trends with this long term impacts of climate change, or is are these outbreaks really a part of natural variability from what you're seeing?

00;16;02;25 - 00;16;30;12
Judah Cohen
Yeah. So yeah, great question. So this is an ongoing debate. Most of my colleagues say, you know, whatever we see with the winter weather, it's natural variability, I argue, is a minority of us that argue that that we see the impact or the contribution of climate change. So I so these stretching events so we had a paper where we argued that these pole of Arctic stretching events are occurring more often over the past 40 years.

00;16;30;12 - 00;16;53;21
Judah Cohen
You could see an increasing trend and the reason for this trend is not natural variability or random or chance, but rather is because the way things are changing in the Arctic, they have favored the way just, you know, just by whatever, I don't know, whatever reason, just the way that the juxtaposition of those changes favors more disruptions in the polar vortex.

00;16;54;12 - 00;16;58;18
Judah Cohen
You know, it's a little bit complicated, but I'm happy to try to get into that. Explain that to you.

00;17;00;05 - 00;17;04;15
Hal Needham
For example, the Arctic being more ice free. I mean, does that does that play into this?

00;17;04;21 - 00;17;37;28
Judah Cohen
Yeah. So there are two important components. One is ice and sea ice melt. I mean, I think that's the one change in the Arctic that people most closely associated with Arctic change are climate change. But the Arctic, the sea ice melt isn't uniform or homogeneous, it's actually happening in focus regions. And that's really important for my for the idea that I propose, you know, a proponent of advocating it's melting quick in the fall winter months is nothing quick is across near northwest Eurasia.

00;17;37;28 - 00;17;56;03
Judah Cohen
So in Scandinavia in northwest Russia, it's called the Barents. Kara Sea. So it's, you know, so that's where the that's where the region are seeing the fastest sea ice melt. So there's a kind of bullseye of heating right in that region because they're losing the ice the fastest. You know, when you expose the ice as a good thermal insulator.

00;17;56;21 - 00;18;05;25
Judah Cohen
So it prevents heat in the ocean, which are a huge reservoir of heat from escaping from the ocean into the atmosphere. When you have a layer rise, you put you know, you peel that ice back.

00;18;05;26 - 00;18;07;20
Hal Needham
Yeah, you're like tapping that energy, right?

00;18;08;08 - 00;18;33;06
Judah Cohen
Yeah. On the song that MJ if you go to like these geothermal springs with them and you see all the if you go there in the winter and it's really hot and you see all the steam coming out, so that happens, you know, over the, over the Arctic Ocean when melt the ice. But I mentioned Siberia. But the other key part of it is that is there's more snowfall now in Siberia because a warmer atmosphere holds more moisture and is super cold.

00;18;33;11 - 00;18;43;09
Judah Cohen
They're really moisture starved. You know, the snow there is not limited by temperatures, is limited by moisture. Now you're getting the atmosphere is moist. Also, I think you're getting kind of a lake effect because.

00;18;44;00 - 00;18;45;02
Hal Needham
More open water kind of.

00;18;45;02 - 00;19;03;27
Judah Cohen
Thing. Yeah, because, you know, same thing happens to us like with Lake Erie, right? Sure. Sure. The beginning of the winter, it's ice freeze. That's when the buffalo typically gets the big lake effect events like we saw this year. But then it freezes and then shut the lake effect machines are now there. It's in reverse. You know, used to be always ice in the Arctic Ocean.

00;19;03;27 - 00;19;10;19
Judah Cohen
So there was no lake effect. But now as it melts, there's more and more lake effect. I mean, that's an idea. Makes sense. But I didn't really.

00;19;11;10 - 00;19;19;28
Hal Needham
How do you think increasing the snowpack in eastern Russia might affect circulation or the, you know, regional and international weather patterns?

00;19;19;28 - 00;19;43;12
Judah Cohen
Yeah. So, yes, I think that there like a couple that melting ice to the west right near Scandinavia heats the atmosphere and then to the east you have more snow and snow has very high reflectivity. It's the most reflective, naturally occurring surface. So incoming sunlight gets reflected back out to space. But also it's again, like the ice is a good thermal insulator.

00;19;43;12 - 00;20;01;14
Judah Cohen
So now I can heat escape from the ocean, can actually escape from the ground into the atmosphere. It put slow down and shuts that down. Also at night, you know, we lose energy to space. Yeah, the earth is giving off energy all the time, just like the sun. But it's over at night, you know? It's losing. There's no incoming solar.

00;20;02;04 - 00;20;09;05
Judah Cohen
That's why we get colder. Snow is a very is the most is very efficient at emitting or, you know, giving off this energy or radiation.

00;20;09;10 - 00;20;28;23
Hal Needham
You know what's interesting, as I hear you talk about this, it seems quite complex where perhaps in the, you know, north of Siberia, over the water, you may have a warmer atmosphere because you have ice free. But then perhaps over parts of Siberia and eastern Russia, it actually might be colder like at night because you have more snowpack that's helping radiate this energy out.

00;20;28;23 - 00;20;30;24
Hal Needham
You know, it seems like it could really change around.

00;20;30;25 - 00;20;38;04
Judah Cohen
And you see that in the temperature trend. So right along the coastline of Siberia, you see a warming trend. But as you head further south.

00;20;38;12 - 00;20;39;15
Hal Needham
It might be a cooling trend.

00;20;39;21 - 00;20;41;12
Judah Cohen
There's a cooling trend. Yeah. Yeah.

00;20;41;25 - 00;21;02;23
Hal Needham
No, that's really interesting. And I used to give a science talk at university of Alaska. I was there for a couple of years and a lot of tourists would come in and just the complex nature and a lot of what's happening in Siberia and eastern Russia does come over to Alaska. You know, the the scientists there said actually during like the Soviet Union, they were getting these great data from Eastern Russia.

00;21;03;01 - 00;21;17;03
Hal Needham
And then I think like in the nineties with the transition politically, a lot of these data started drying up. And an Alaskan researcher said, you know, we really need to know what's happening upstream in Siberia to forecast our weather here. You know, so just interesting how it's all connected.

00;21;18;06 - 00;21;40;25
Judah Cohen
Yeah. I mean when I first it was, you know, again, arguing for these ideas. It was very counterintuitive because, again, like I was mentioning with like with the polar vortex, it flows from west. These typically weather system move west. So we don't think of how severe is impacting our weather in the west. But it's, you know, it's not you know, our weather is coming from the West Coast and the Pacific.

00;21;41;07 - 00;22;01;19
Judah Cohen
People didn't couldn't understand why. Why are you saying Siberia can impact our weather? How does it get here? But I think maybe, you know, people appreciate more and more of that, how everything is interconnected. And because Eurasia is such a big landmass, it really is very important. It was it's definitely very important for driving the behavior of the polar vortex.

00;22;02;12 - 00;22;09;05
Judah Cohen
And certainly if you then think that if you did agree that the polar vortex influences our weather, then it's easy to make that connection.

00;22;09;05 - 00;22;25;04
Hal Needham
But do you know, were you saying when the stratosphere warms up over like so, this is obviously the layer above the troposphere, when it warms up over the polar vortex area that can get these tropospheric like cooling to kind of be on the move and elongate more? Is that true?

00;22;25;17 - 00;22;54;03
Judah Cohen
Yeah. So what happens is I don't think we fully understand, but what happens first in with the polar vortex in the stratosphere that will happen about two weeks later in the troposphere. So when you get these big disruptions of the polar vortex, what's called this time stratospheric warming, is you have this very strong warming over the Arctic, this big high pressure that forms over the over the Arctic and the cold air and the low pressure gets displaced much further south.

00;22;54;03 - 00;23;24;08
Judah Cohen
And that that kind of is really a river bear that's associated to both worlds. It gets pushed also much further south. And then two weeks later, we see the same thing happening. Excuse me, in the troposphere. Okay, the jet stream, you get this, it gets warm over the Arctic, a big high pressure over the north, somewhere over the Arctic, near the North Pole, and the cold air that was previously over the Arctic ice display south, the kind of get lower pressure into the Trump, you know, in the mid-latitudes.

00;23;24;17 - 00;23;52;08
Judah Cohen
And the jet stream is displaced equator where they're southward. So yeah so so at first happens in the stratosphere and then it happens in the tropics here two weeks later. Yeah, I think we understand why. So that's but yeah, you know, it was a coincidental, you know, kind of connection there. You know, I would say it's random, it's not physical, but it can be used to make, you know, these longer range forecasts because we kind of know, oh, we see this big change in the stratosphere.

00;23;52;08 - 00;23;54;23
Judah Cohen
It's coming to the tropics. Frans Well, that's really interesting.

00;23;54;23 - 00;24;04;10
Hal Needham
And when it's on the move, it sounds like high pressure builds over the Arctic Ocean and you get low pressure moving down through Canada and the continental US, bringing this really cold air with it.

00;24;04;21 - 00;24;23;15
Judah Cohen
Cool. Yeah, right. With the air. Does those storms bring the cold air with it? And it can also increases the chance of getting a snowstorm because of the storm track. You know, are those areas of low pressure that are moving along the jet stream or further south? We're on the north side of that. You know, those moving storms, you're more likely to get snow.

00;24;23;19 - 00;24;28;03
Judah Cohen
Whereas if it's much further north into like Canada or something, then you're going to get rain from those.

00;24;28;03 - 00;24;35;24
Hal Needham
So this is really a displacement of the jet stream. And like you're saying, storms can track along that you could get some big potentially get some big snow producers.

00;24;36;01 - 00;24;36;26
Judah Cohen
Yeah, Yeah.

00;24;37;15 - 00;24;45;18
Hal Needham
Dude, I really appreciate you coming on the podcast. How can our listeners find you your research? I don't know. Are you on social media or just different journals or different platforms?

00;24;46;12 - 00;25;01;12
Judah Cohen
Okay, so I mean, I write journal articles, but, but, but I'm active on Twitter at a junior 47. Not that the greatest handle there. If I'd known I'd be so active on Twitter, I might have.

00;25;01;17 - 00;25;04;02
Hal Needham
And that's J. Jude, age 40.

00;25;04;02 - 00;25;06;10
Judah Cohen
Seven, ADR, age 47.

00;25;06;16 - 00;25;06;27
Hal Needham
Okay.

00;25;07;16 - 00;25;13;27
Judah Cohen
I also have a blog. I have a weather blog where I try to make these longer range forecasts. So in the winter months, it's it's every week.

00;25;14;20 - 00;25;33;20
Hal Needham
Yeah. I mean, I, I checked you out on Twitter this week and I thought it was really useful stuff. You were just giving snapshots of what might be coming down the road. And I know for our listeners on the Gulf Coast, they're worry about freezes. I know for some friends of mine that work in like the ski industry in the Northeast, they're having a rough season and they're all wondering, you know, is cold air going to come back?

00;25;33;20 - 00;25;41;09
Hal Needham
I mean, the type of stuff you're putting out with these, you know, looking mid to long range, I think a lot of people would be interested to see that I'm out.

00;25;41;10 - 00;26;01;10
Judah Cohen
You know, I think I think, you know, there's there's an interest there but it's if you do if you blog, if you search Google search to the call blog, I'll be like the first thing that comes up. It's called the Arctic Oscillation Polar Vortex Blog. But it should be easy enough to just search and find it. So every week there's an update to it.

00;26;02;01 - 00;26;12;02
Judah Cohen
It's made public on Wednesdays and Monday, so you have to pay a little bit to see it in advance. But on Wednesday, it's is open. You know, it's free to the public. Anybody can read it due to.

00;26;12;02 - 00;26;21;23
Hal Needham
And in the beginning of our conversation, you said you do a lot of seasonal forecasting. Do you forecast as well for like summer events, for tropical events, or is most of your focus really winter events?

00;26;22;00 - 00;26;46;26
Judah Cohen
Yes. I mean, I know we make seasonal forecasts all year long. Okay. So I mean, spring, summer, fall, winter. I mean, I'm just best known for the winter. Sure. Yeah, I think the winter is much more challenging, to be honest. Summer's gotten less interesting because there's been this just basically monotonic warming trend in winter has been more complex, and I think the polar vortex has made that warming more complicated.

00;26;46;26 - 00;26;49;13
Judah Cohen
It hasn't been like a straight line more, but I think we're getting.

00;26;49;20 - 00;27;02;08
Hal Needham
Yeah, and it seems like we have more of a gradient in the winter right across the hemisphere, you know, like in the in the summer. The temperature difference between northern Canada and the Gulf Coast, it tends to be less, I guess, in general than in the wintertime, right?

00;27;02;19 - 00;27;11;17
Judah Cohen
Yeah, Yeah, that's absolutely true. And that's why the jet stream is stronger in the winter. It's also further south. But yeah, I mean, yeah.

00;27;11;17 - 00;27;19;21
Hal Needham
So yeah. Judith, thank you so much for coming on the podcast. Well, we'll make sure that we follow you online and our best wishes for you and, and your research.

00;27;19;21 - 00;27;21;08
Judah Cohen
Dagen I really appreciate that.

00;27;22;01 - 00;27;44;14
Hal Needham
Thanks Judith, for sharing your insights about the science behind these severe weather outbreaks. I really like how you describe Siberia as the refrigerator of the northern hemisphere. It's important for our listeners to understand that this very cold air does not simply just show up in a place like Chicago. It has a source region and then a long distance to travel before inflicting its impacts on the central and eastern U.S..

00;27;45;16 - 00;28;09;23
Hal Needham
Some very cold air can also be sourced from places like Interior, Alaska and Canada's Yukon territories as well. And I wanted to get someone on the podcast who could share a firsthand experience about living in such extreme cold. I couldn't think of anyone better than science writer and adventurer Ned Roselle, who has lived for more than 35 years in interior Alaska and was a star of Geo Trek podcast.

00;28;09;23 - 00;28;22;16
Hal Needham
Number three. Nate is a close friend of mine and happened to be visiting me in Galveston this week, so we recorded this segment live at my home in Galveston, Texas. Thank you so much for taking time to come back on the podcast.

00;28;23;19 - 00;28;24;14
Judah Cohen
Thank you. Well.

00;28;25;01 - 00;28;43;20
Hal Needham
Then we're talking about these cold arctic weather outbreaks in the lower 48. And what we're hearing is a lot of this polar air, this arctic air is originating in northern Canada and Alaska and Siberia. And then it's on the move down to the lower 48. You've lived in Alaska more than 35 years. You've experienced a lot of this tremendous cold.

00;28;43;28 - 00;28;47;17
Hal Needham
Well, what's the coldest temperature that you've lived there?

00;28;47;17 - 00;28;49;19
Judah Cohen
-57 Fahrenheit.

00;28;50;13 - 00;28;58;23
Hal Needham
Wow. -57. So that's 89 degrees below freezing. I mean, what is it like to experience a temperature like that?

00;29;00;18 - 00;29;30;27
Judah Cohen
Yeah, well, you're sort of confined to the indoors because those temperatures, you know, your flesh will freeze and you'll lose fingers and limbs if you're out too long. But nobody usually dies in Alaska because we all have these great adaptations of buildings and great clothes. And believe it or not, cars still run at that temperature. If you've sort of preheated the oil and or have a garage.

00;29;31;04 - 00;29;32;22
Hal Needham
So you're plugging the cars in, right?

00;29;33;19 - 00;29;58;13
Judah Cohen
Yeah, we cars that are not garage in mine never have been up there in Fairbanks, Alaska, in the middle of Alaska, have what we call frost plug heaters. And it's basically heating element that you put it's in contact with your cool. It just sticks out there like a tongue and you plug in and that keeps your coolant a bit warmer.

00;29;58;23 - 00;30;07;23
Judah Cohen
So it sort of pre warms the engine when it's real cold C minus. No, we usually plug in it like zero degrees Fahrenheit or colder.

00;30;08;18 - 00;30;15;27
Hal Needham
Yeah. It's amazing. It's amazing to to see shopping centers universities and see parking lots adapted with all these plugs right.

00;30;15;27 - 00;30;43;17
Judah Cohen
Yeah. You have these posts out in every parking lot and they have an outlet on them. So yeah, if you wanted to plug in your TV there, you could watch it. But mostly it's for you have to plug in these frost plug heaters on your car. And we also have battery blankets or just a heat pad that your battery sits on that sort of keeps it a little warmer than the air temperature.

00;30;43;29 - 00;30;50;08
Hal Needham
Don't car tires start kind of not getting round at a certain temperature as well. They start kind of squaring off a little bit.

00;30;50;21 - 00;31;14;19
Judah Cohen
Yeah, that was I don't know if new tire technology is improved, but or if it hasn't been that cold recently, which is also a possibility. But yeah, back in the day you would you would leave your car park, set in -40 and then when you got going again, if they weren't totally inflated, there'd be a flat spot where the car was sitting putting all its weight on it.

00;31;14;19 - 00;31;22;22
Judah Cohen
So you hear this rhythmic thunk for a while it would go away after a few hundred yards, but it's always a little unnerving.

00;31;23;00 - 00;31;26;13
Hal Needham
You know, The physics of things seem to change a little bit when you're in really extreme cold.

00;31;27;26 - 00;31;54;16
Judah Cohen
Yeah, yeah. There's a lot of things we notice, like sound waves really propagate well for some reason. Like you hear you can hear a train from miles away and it sounds like it's coming down your street and airplanes sound kind of different really loud as they're going overhead. Yeah, but amazingly, things sort of work at that temperature. Yeah.

00;31;54;16 - 00;32;01;28
Judah Cohen
Light bulbs work outside. Dogs still bark. Yeah. And cars roll along if they've been treated right.

00;32;02;12 - 00;32;10;18
Hal Needham
Yeah. It seems like society's adapted for it, right? Like you said, you're not having a lot of fatalities. And these extreme cold events, it seems like Interior Alaska is prepared for them.

00;32;11;20 - 00;32;38;02
Judah Cohen
Yeah, we have what would be considered super insulated houses like compared to here. We still have some gaps and stuff, at least in my house. But yeah, I notice we had we haven't been above zero like it's now January. We haven't had above freezing temperatures since probably October. Yeah, mid-October.

00;32;38;02 - 00;32;45;16
Hal Needham
And that's pretty common that the interior could go really from what, mid-October until maybe mid-March without getting above freezing.

00;32;45;16 - 00;32;51;06
Judah Cohen
Yeah, that's exactly right. Yeah. Yeah. So that's a long period with Yeah.

00;32;51;09 - 00;33;09;15
Hal Needham
A cold and that's a big difference I think from almost anywhere in the lower 48. Even you go to places like Minnesota, right, They'll often say we're the icebox of the country and they'll get to sometimes 30 below, 40 below. But then the next week they're up in the low forties, above or 50 above. In interior Alaska, you don't really get the breaks like that sometimes.

00;33;10;01 - 00;33;28;03
Judah Cohen
Yeah, it's fairly constant up there, which we like for our snowpack. Like we get snow in November often and we can ski and ride our snow banks on that for and snow machine snowmobile for four months. Yeah.

00;33;28;15 - 00;33;52;01
Hal Needham
Yeah. It really stays a long time. Now in this podcast you two Cohen was talking about these Arctic outbreaks that you know really the source regions are up there closer to the Arctic. Once the air starts on the move, we get a really strong cold front. It's related with the polar vortex and all of a sudden we get these blasts that come down often with very stormy, windy weather, even blizzard conditions like we've recently seen in western New York.

00;33;52;01 - 00;34;09;10
Hal Needham
So the cold air is on the move. It shows up with really strong winds and things like that. But we know, like you've explained to me in interior Alaska and these places, these source regions, sometimes when you get the really cold air, there's actually no wind at all. Describe for me the typical conditions when you're really getting that cold air.

00;34;09;10 - 00;34;13;18
Hal Needham
I mean, what's it like? What do the skies look like? What does it feel like? Do you have any wind?

00;34;14;29 - 00;34;56;22
Judah Cohen
Yeah, we often have no wind. We live in Fairbanks, Alaska, is a very windless place because it's got like these hills on three sides that shade us from wind. And that's when causes mixing. And we have what we call temperature inversions, where the air is so stagnant and non moving in the bowl where we live that after a while this sets up, we're low parts like stream beds and bottom of the valleys will be can be 40 below.

00;34;56;22 - 00;35;18;00
Judah Cohen
And then you go on top of a 2000 foot hill nearby. You go from 40 below on the low to, you know, maybe plus ten or something. So he's really extreme temperature gradient set up when there's no wind and when when it does come, we'll mix that up and warm things up on the surface.

00;35;19;19 - 00;35;29;12
Hal Needham
And a lot of times there's a lot of ice fog as well, right? When we're in these temperature inversions, the cold air, it's very dense. It's down low. And a lot of times you have this layer of ice bogged down in the valleys as well, right?

00;35;29;25 - 00;35;53;16
Judah Cohen
Yeah. Fairbanks is one of the only towns in the U.S. where ice fog is occasionally part of the forecast. And what it is, it's just water vapor with that. What it is is water vapor that can't be sort of dissipated because it's so cold. So it just kind of hangs in the air like cotton candy. And that happens.

00;35;53;16 - 00;36;14;20
Judah Cohen
That doesn't happen often these days because we're getting warmer, but it happens like -35 when the air temperature reaches that. Then you'll notice the car going by in its exhaust just hangs there like it's a solid, you know, this solid stream or of weight. And that all adds up because we have this sort of windless condition in our town.

00;36;14;20 - 00;36;37;02
Judah Cohen
And it kind of, yeah, fills up that box after a while so that all the water vapor, including open water sources like our river going through town, it's open because we have a power plant that uses the river for cooling and it warms up the river somewhat. So it's not all iced over the little parts that are open.

00;36;37;02 - 00;36;59;07
Judah Cohen
And there's a lot of steam coming off that. And one researcher in his classic paper on Ice Fog, he even calculated how many dogs Fairbanks had like 2000 dogs back then, and he counted their exhalations, you know, the water vapor that came out of the dog's mouth as part of his calculation for this low visibility problem. Yeah.

00;36;59;07 - 00;37;19;03
Hal Needham
Any moisture, right? It's crystallizing in the ice crystals and it's just hanging there. And for our listeners, it's again, you have hillsides around Fairbanks and places like that. But when you when you come off the hillside, you go into the valley, all of a sudden you're in this very, very dense crystal like ice fog. It's very dense. And again, there's no wind, there's no mixing, and it's very cold in the valley.

00;37;19;03 - 00;37;20;11
Hal Needham
Bottoms.

00;37;20;11 - 00;37;29;17
Judah Cohen
Yeah. And cars produce that, too, because one of the byproducts of burning gasoline is water. And that comes out of the tailpipe. And yeah, when it's that cold, it just sort.

00;37;29;17 - 00;37;48;00
Hal Needham
Of you see kind of this cloud behind the cars. Right. Really. And the other thing too, you mentioned 35 below. What might really surprise our listeners is that could be the low temperature to start the day. And then in the afternoon you might not be that far still from 35 below. Right. You're not really seeing a temperature change day or night in some of these events.

00;37;48;14 - 00;38;26;29
Judah Cohen
Yeah, because Fairbanks is so far north, we're about 120 miles south of the Arctic Circle that the sun doesn't really have much punch because we lean so far away from it this time of year during winter that, yeah, you can't feel it on your cheek even if it's a sunny day and it's midday and yeah, really, if you watch your temperature graph there's not much of thaw to in mid-winter, it's just sort of flat lining and it's being affected by things other than the sun.

00;38;27;21 - 00;38;43;16
Hal Needham
Yeah, that's right. That's a good point. Right. You could be 35 below in the day and then at night, if you get a little bit of wind or some clouds move in, all of a sudden you could go up 15, 20 degrees at night. Right. So it's it's not really following the normal pattern of sun and dark. Right.

00;38;43;23 - 00;38;57;02
Judah Cohen
Right. It will in sort of mid-February, start getting that the sun has a little more punch and then it has a lot more punch, you know, into March and April. But yeah, right now is a dark, quiet time up there.

00;38;57;18 - 00;39;17;02
Hal Needham
Then Thanks for coming on the podcast explaining what it's like. A lot of our listeners have never experienced that type of extreme cold. And it's interesting because we're seeing the effects of that. We're seeing some of those air masses more and more moving down to the lower 48 states impacting the Central and eastern U.S. But it's kind of interesting to hear from someone who lives in one of the source regions where this cold air is coming from.

00;39;17;02 - 00;39;18;06
Hal Needham
And just to hear what that's like.

00;39;19;08 - 00;39;25;26
Judah Cohen
Yeah, well, I'm glad to be visiting you down here in the South for a little break from that.

00;39;26;00 - 00;39;41;03
Hal Needham
We're recording this in my place in Galveston, Texas, and it came down for a week to see some sunshine warm up a little bit. It's it's that time of the year where you can be below freezing or really below zero for many days in a row up in Fairbanks. So great to have you here. Hopefully you're thawing out and enjoying the visit.

00;39;41;17 - 00;39;43;05
Judah Cohen
Yes. Thanks, Hal.

00;39;44;08 - 00;40;04;05
Hal Needham
Thanks so much, Judah and Ned, for coming on the Geo Track podcast. Here are the main points I got from these interviews on this podcast. Episode Number one The Polar Vortex is a large area of low pressure and cold temperatures surrounding the poles. When the polar vortex is strong, the air remains bottled up at high latitudes and the jet stream stays really tighter.

00;40;04;15 - 00;40;29;06
Hal Needham
When it weakens the jet stream can dip considerably and cold air drives far to the south, bringing impacts to places like the southern part of Canada and the continental U.S.. Number two, Dr. Cohen was sharing that there are different kinds of poor polar vortex displacements. The one with the biggest impact on the U.S. is an elongation of the polar vortex as a boundary of this area stretches far to the south of its normal territory.

00;40;30;00 - 00;40;54;07
Hal Needham
Number three, I thought it was really interesting how Dr. Cohen talked about how interconnected these climate patterns are when we discuss the impact of climate change. He pointed out that the Arctic climate is not changing in a uniform way. One of the areas that has observed substantial of sea ice is the Barents and Kara Sea region of the Arctic Ocean Basin, north and east of Scandinavia and off the coast of northwest Russia.

00;40;54;26 - 00;41;18;12
Hal Needham
He out how open water in this region is increasing snowfall in Siberia, which can lead to colder temperatures in the continental part of Siberia. This has a large implications for the northern hemisphere. Dr. Cohen stated that Siberia is the refrigerator of the northern hemisphere, and warmer cold patterns in that region often precede what's happening in the central and eastern U.S. by around two weeks.

00;41;18;24 - 00;41;39;26
Hal Needham
This is a good reminder of how interconnected the climate is. Number four and then Rosetta's account of what it's like to live in one of these source regions of extreme cold was interesting and eye opening as he described a world that few of us could imagine in his world in interior, Alaska, the temperature might stay locked at 36 degrees below zero Fahrenheit, night and day.

00;41;39;26 - 00;41;59;28
Hal Needham
In a strong temperature inversion, visibility in the valleys can fall to near zero on these days as ice, fog blankets the region. He also described pictures of people plugging in their vehicles so they'll start when they're living in such extreme cold. So, again, that really dramatic cold that a lot of us, for example, in the lower 48 states have never really experienced before.

00;42;01;03 - 00;42;24;15
Hal Needham
The good news of these extreme Arctic outbreaks that reached the central eastern U.S. is that the cold weather moves from source regions like Siberia, Alaska, the Canadian Yukon, and then moves as an air mass to the south and east. This enables wet weather models to predict their arrival and gives ample warning to people in harm's way. Take the Christmas 2022 Arctic outbreak in central and eastern U.S..

00;42;24;15 - 00;42;45;15
Hal Needham
Although extreme cold did not really show up in Alaska's north and west coast with that event, It did show up in Fairbanks, where Ned Roselle lives as the temperature was at least 20 degrees colder than normal for five consecutive days. As the air mass moved east, it intensified with Toque Alaska, near the Canadian border, experiencing temperatures at least 33 degrees below normal for five days straight.

00;42;45;29 - 00;43;11;05
Hal Needham
Then we all followed this extremely cold air as it barreled through many Canadian provinces and slammed the northern Rockies and the plains states of the U.S. As the air mass was on the move, winds picked up and it became a formidable winter weather event, packing strong winds, very cold temperatures and blizzard conditions. Number five Finally, as research evolves on this topic, you can follow mid and long term forecasts from Juda Cohen.

00;43;11;15 - 00;43;31;16
Hal Needham
You can find him on Twitter at Juda 47 or just do a web search for Judah Cohen blog. These forecasts are updated weekly and again, they're giving projections of what we can expect looking down the road. As far as the next out really Arctic outbreak getting into the continental U.S.. Special thanks to Judah and Ned for coming on this podcast about extreme cold.

00;43;31;24 - 00;43;51;17
Hal Needham
It's a topic that's highly relevant for people from the Arctic and Subarctic all the way down to the subtropics, where freezing temperatures can inflict impacts all the way, for example, along the U.S. Gulf Coast. Finally, as research evolves on this topic, you can follow mid and long term forecasts from Judah Cohen. You can find them on Twitter. His handle is at Judah.

00;43;51;18 - 00;44;16;01
Hal Needham
47. Or just do a web search for Judah Cohen blog. The forecast are updated weekly. And again, what he's doing here is pretty unique. He's looking really upstream and really focusing a lot on what's happening in Siberia. Again, what's happening there may impact the central and eastern U.S. two weeks later. And again, to reiterate some of these connections, he's finding that having more open water in the Arctic Ocean and in the Barents.

00;44;16;01 - 00;44;39;13
Hal Needham
And Kara Sea, again northeast of Scandinavia, there can increase moisture in Siberia. We often think of snow happening when it's cold, but in Siberia, it's plenty cold to get snow any time. Historically, snow has been limited by not having enough moisture with the more open water because of melting sea ice. We're seeing more snow in Siberia. And snow actually really caused the climate for two reasons, he explained.

00;44;39;13 - 00;45;00;19
Hal Needham
The reflectivity of snow, when we have incoming sunlight, it can reflect a lot of that sunlight, all of that solar energy and also earth is always radiating heat. And so when you have snowpack at night, you can really radiate heat more efficiently. And so more more open water in the Arctic and in the Kara and Bering Sea, we're seeing more snow in Siberia, more snow in Siberia.

00;45;00;19 - 00;45;18;09
Hal Needham
The temperatures are colder and that really is upstream from what's happening and what's coming in to North America. It's fascinating how all these things connect. That's what Dr. Cohen is doing in his research and his blogging. And again, you can find him on Twitter and on his blog to see really what's happening and to see a forecast and get a snapshot of what we might expect down the road.

00;45;18;29 - 00;45;36;09
Hal Needham
Special thanks to Judah and then for coming on this podcast episode about Extreme Cold. It's a topic that's highly relevant for people from the Arctic and Arctic all the way to the subtropics. That's right. All along, for example, the I-10 corridor of the US Gulf Coast, we've seen big freezes in recent years as far south as the Gulf Coast.

00;45;36;17 - 00;45;55;23
Hal Needham
And people even there are very concerned about cold weather outbreaks. I'd like to thank our marketing team as well for their help with disseminating each podcast episode. Our team has sent Earth Baker, Ashley Anderson, Jeremiah Long, Christopher Cook, Amy Wilkins and Courtney Booker, and of course, a huge thank you to all of our faithful listeners for your interest in this podcast.

00;45;55;29 - 00;46;07;29
Hal Needham
Stay warm, everybody, as we push through these remaining weeks and months of winter, we're kind of getting into the second half now. I'm Dr. Help and I'll catch you on the next episode of the Geo Trek podcast.

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