Tornados - Dr. Jeff Masters Biography

0:00 We're going to be interviewing next, Jeff Masters, 0:04 Director of Meteorology for the Weather Underground, 0:07 and a graduate of the University of Michigan. 0:10 Jeff has written an article in the past about what would happen if 0:14 a tornado hit a very populated area in the United States. 0:18 So Jeff, in your article, 0:20 you talk about in particular, Chicago 0:23 and you're basing this on some other research that was done in the past by Josh Wurman. 0:29 So, just tell us about what the findings were about? 0:33 How bad could it be? 0:34 What happens if a F5 0:37 or F4 tornado hits a populated area like Chicago? 0:41 Yeah, the thing about tornadoes is they generally 0:43 occur over a very sparsely populated areas. 0:46 The Midwest has got a lot of wide open spaces, a lot of farmland. 0:50 But a couple of places where we do have a lot of people packed in a small area, 0:55 Chicago is about the most densely populated city in the Midwest, 0:59 a lot of people per square mile there. 1:01 So, if you get one of these high end EF4, 1:03 EF5 tornadoes blitzing through Chicago in one of these densely populated areas, 1:09 you could have about 100,000 people subjected to the winds of a EF5 tornado 1:14 and figuring a death rate of somewhere or few percent per each building, 1:18 you can get easily 10,000 people killed in a tornado 1:22 which would be an unheard of catastrophe. 1:25 Ten thousand is just unthinkable. You're right. 1:28 So, the worst weather events that have happened are less than that, as I recall. 1:36 Yeah. In the US, the great Tri-State Tornado is the world record holder 1:40 for the deadliest US tornado, 695 people killed. 1:44 That was way back in 1925. 1:46 Since 1953, we've only had one tornado in the US that has killed more than 100 people. 1:52 That was the 2011 Joplin, Missouri tornado which killed 158. 1:57 So describe, in addition to the number of people there, 2:04 are the structures capable of protecting people? 2:11 Structures are getting better. 2:13 I mean, we're always building to higher building codes in general. 2:16 So, the death toll is less than perhaps 50 years ago it would have been. 2:21 But yeah, you put a lot of people in the way of harm and they're going to get killed 2:25 because structures, especially single family homes 2:29 can't withstand the winds of an EF5 tornado. 2:31 It simply will clean them off down to the foundation. 2:34 Now in Chicago, a lot of those structures where 2:37 people live are multistory apartment buildings. 2:40 Those will not be completely leveled and the death rate in 2:43 those structures is anticipated to be perhaps a factor of five or 10, 2:47 even less than single family homes. 2:50 Just people watching who are in Chicago and maybe concerned at the moment, 2:55 we're not just talking about Chicago, 2:57 this could be any number of large cities. 2:59 We've had Joplin, we've had Tuscaloosa in the past few years, 3:03 and many cities, large cities do sit in 3:06 what we'd call Tornado Alley or places prone to tornado. 3:10 So, are there other cities you'd be concerned about? 3:14 Probably the biggest concern is Dallas because it's highly populated and it 3:19 also lies in a more tornado prone area of the country than Chicago. 3:24 Also Oklahoma City is a danger. 3:27 It's in the highest incidence for 3:29 a tornado area of the US but it's a little bit more spread out. 3:33 There aren't as many people concentrated there and 3:35 people in Oklahoma City are very tornado aware. 3:38 I mean, they get tornado warnings every year, virtually. 3:41 So, they've got a lot of experience dealing with them. 3:44 In fact, in Oklahoma City, famously, 3:46 they've had more than their fair share of F4 and F5 tornadoes. 3:51 Moore, Oklahoma, South of Oklahoma City has been hit a couple of times in 3:55 the past 10 years or so by tornadoes that were very powerful, F5 tornadoes. 4:02 So, as I understood it from the articles, 4:06 you look at the number of people who died in a tornado like 4:09 that versus the density of population, 4:13 and then extrapolate to a more densed population. 4:19 That's right. Yeah. 4:21 In Oklahoma, I don't know. 4:22 Yes, they are tornado aware 4:24 but they don't often have as many underground facilities, 4:30 don't have basements, necessarily 4:32 and perhaps, there are more mobile homes in some parts 4:37 of the country than others and that's got to come into play in these estimates as well. 4:41 Chicago wouldn't have that mobile home density that a more rural area might have. 4:47 That's true. St. Louis is another city of concern 4:50 because it's also in Tornado Alley and has a large population. 4:53 Sure. And Kansas City, 4:56 Omaha is on the way. 4:58 So, there are lots of cities out there and the Southern cities as well. 5:02 We certainly have a number of F4, 5:04 F5 tornadoes possible in the Southern states. 5:07 So, moving forward then, 5:09 a huge concern here for a catastrophe to happen should a tornado hits a large city. 5:15 The next logical question is what is the probability or 5:19 are there reasons to believe that in the future, that these sort of F4, 5:24 F5 tornadoes are likely to become a change in 5:28 either frequency or intensity because of a warming climate? 5:34 Yeah, EF5 tornadoes are really rare. 5:37 Since 2011, the span from 2012 to 2017, 5:42 there were only one, two, three, 5:44 four, five, counting seven or so of them. 5:46 So around one or two a year and it's considered, we get a thousand tornadoes a year, 5:52 I mean there are like one in a thousand events. 5:55 But back in the year 2011, 5:57 we had nine EF5 tornadoes. 5:58 So what happens is they get concentrated in these bursts and these outbreaks. 6:03 And there's evidence over the past 20 or 30 years that when we do get tornado outbreaks, 6:09 they tend to be larger, 6:11 we're getting more tornadoes, 6:13 And there's speculation that that could be due to a changing climate. 6:18 But there is a lot of unknowns about this because 6:22 the reason that these outbreaks are getting bigger 6:25 is because of an increase in what we call wind shear. 6:28 That's the turning or the change of wind speed or wind direction with height, 6:33 which imparts a spinning motion to get the tornado going. 6:37 It's theorized that in a future climate where the atmosphere is warmer, 6:42 the jet stream move further to the North, 6:45 and the jet stream is the primary mechanism that causes 6:49 this wind shear needed to get strong tornadoes. 6:52 So the theory says that wind shear should 6:56 decrease in the future as the jet stream moves further North. 7:00 But here, we're observing that actually, 7:02 the shear in these major outbreaks over the last 20, 7:06 30 years is actually increasing. 7:08 So there's a disconnect between what we expect to happen in 7:11 a warming climate and what we're actually observing as far as tornadoes go. 7:15 So, it's uncertain why there is this increase in 7:18 the number of tornadoes and 7:20 these large outbreaks because of climate change, because it doesn't fit the theory. 7:24 So, that's a big area of research for the future. 7:29 And I might add the other main ingredient that 7:32 we're looking at for tornadoes, in order to get a good tornado, 7:35 you need a strong thunderstorm. 7:37 Which means you need lots of warm unstable air from the heating of the ground. 7:43 And of course in a warmer climate, 7:44 you're going to have warmer air temperatures which would lead to more instability, 7:49 more unstable air creating strong thunderstorm updrafts. 7:52 So that influence is expected to increase with a warming climate. 7:56 But as yet, we have not observed 7:59 that particular effect coming into play as far as tornadoes go. 8:02 So, it's still a large area of unknown. 8:06 We got to do a lot more research before 8:08 we're going to be able to conclusively say there's 8:10 a signal yet in the noise of all these observations we take about tornadoes. 8:15 It's a really tough problem. 8:17 You hit it on the head the two main things worrying about with tornadoes. 8:21 A, is the sort of convective potential of the atmosphere and how will that change and 8:28 the convective potential has to do with 8:29 how much warm moist air is packed in near the surface, 8:34 and where are the conditions above it and how that will change over time. 8:38 Then the second part is what you're calling the wind 8:41 shear or helicity in the storm and how is that going to be 8:45 changing over time. We'll be talking about that in detail about how 8:50 those two are forecast to change in the future, given the climate projections. 8:55 There is actually some evidence that it's not necessarily 8:59 the convective potential that's going to be changing all that much, 9:02 but it's perhaps the change in that rotation there, 9:06 in that wind shear that might be causing 9:09 the potential for more tornadic storms in the future. 9:13 But you're right. This is an uncharted territory 9:16 and we can say here and speculate all we want to 9:19 but we just don't know yet at the moment. 9:22 Yeah, it's also interesting that the average conditions, 9:27 what can we expect on average the wind shear will go down as the climate warms. 9:31 But it turns out that a 2013 paper showed that we shouldn't be looking at the averages, 9:37 we should be looking at the extreme events. 9:40 During the extreme events, it turns out that we're actually 9:43 seeing an increase in wind shear, 9:45 these extreme tornado causing sorts of 9:47 days when we're most prone to get these large outbreaks. 9:51 It remains to be seen why we're seeing 9:54 that extreme situation increase in recent decades. 9:58 Is it climate change? Is it natural variability? 10:00 Well, we'll probably be able to figure that out in 10:02 the next 20 or so years as the whatever natural cycle 10:06 this is will presumably go back down away from creating these larger events we're seeing. 10:12 Another factor in tornadic formation is got to be this low level jet. 10:18 There's this air that transports moisture from South and 10:21 North over the plains and elsewhere and how that changes in the future. 10:26 You mentioned the fact that the jet stream may be shifting in its location 10:30 as the Polar regions melt and then where that jet stream winds up meandering, 10:36 all bets are off and how that's going to change 10:38 but if you decrease the temperature gradient presumably, 10:42 you're going to change or maybe decrease the strength 10:45 of the jet stream has that affect all the other parts is- 10:50 That's why we're going to have graduate students for a long time, 10:53 I guess, who's trying to work these things out. 10:56 Tornado outbreaks happen worldwide. 10:58 Famously, they happen in the United States and 11:02 the United States is probably the place with greatest frequency of tornadoes. 11:05 But when we look at the top 10 most deadly tornadoes in history, 11:10 USA is not in the top three and surprisingly, 11:16 the greatest number of tornado deaths happens in Bangladesh. 11:20 Can you speak to why Bangladesh? 11:23 Bangladesh has a large area of very warm moist air 11:29 that invades it in the tornado season they have there 11:32 because they're close to the Bay of Bengal which has got very warm waters. 11:36 And when that warm moist air collides with some of 11:38 the cold dry air coming down from the Himalayas, 11:41 then you get a situation where you can get some strong tornadoes. 11:45 And they don't get very many, 11:47 they only get five or 10 tornadoes a year in Bangladesh, 11:50 but they're very vulnerable to tornadoes 11:52 just because there's so many people in Bangladesh and the construction is not as 11:57 strong as say, you'd get in the US. Also they 12:00 don't tend to have basements because Bangladesh is very low lying. 12:03 So, you combine the five or 10 tornadoes with a lot of people that are vulnerable, 12:08 then you're going to get a large death toll. 12:09 What is it you imagine we could do in 12:12 research realm that is going to give us more information and 12:15 help us be able to forecast these storms earlier so that people in Chicago would have, 12:21 for example, a longer time to prepare tornadoes bearing down on them? 12:27 We really need to invest in more field research. 12:30 Tornadoes are hard to observe. 12:32 They tend to blow away whatever measurement estimates we put in 12:35 their way and they're very rare, especially strong tornadoes. 12:40 So, we need to get a lot more data out in the field on just how they form, 12:45 how they move, how they intensify. 12:47 And to do that, we need to spend a lot of dollars, 12:50 we need to put millions of dollars worth of equipment out there, 12:53 we need to put a lot of people out there. 12:54 There have been a number of field studies in recent years looking at tornadoes. 12:58 In fact, there was one in the Southeast US called SE Vortex 13:01 recently and they plan to continue that study in the future. 13:05 Unfortunately, that study has had its funding 13:08 projected to be cut by the latest budget proposal 13:11 and I think that would be a big mistake because the 13:14 Southeast US is uniquely vulnerable to tornadoes. 13:17 We don't understand them as well there and 13:20 some of the highest death tolls we've seen in recent years have been in Alabama, 13:25 Mississippi and particularly, in the year 2011 when we had 13:28 some really hellacious tornado outbreaks in that area. 13:31 It's been somewhat easier for us to study tornadoes out in 13:35 the Great Plains in part because they are plentiful, 13:39 in part because the air is drier there 13:42 so we have this clouds at a higher base and we have 13:44 more opportunity to see them from a distance. 13:47 And also must be blunt, 13:49 there are fewer trees out there. 13:51 So, it's a greater visual range. 13:53 It's harder, of course, in the Southeast where they have lots of trees 13:58 to go chasing these storms, 14:00 makes it much, much more dangerous. 14:02 But you're exactly right because we can use radar technology to a point 14:07 but that curvature of the earth doesn't allow you to use the radar to get 14:11 down to the surface to see where the surface winds are in the vicinity of a tornado. 14:16 So you really have to have ground troops, if you 14:18 will, to get right in there and make those measurements. 14:21 So, moving forward, we need more of this kind of research to happen 14:25 but you don't see that being high on the list of our current priorities? 14:30 No. I mean, the current administration is very anti-science, they've proven that. 14:34 They're not very keen on providing funds for research. 14:39 Either tornadoes, hurricanes, weather in general, 14:42 they're all subject to cuts, it looks like. 14:46 I want to thank you, Jeff for spending some time with us and to talk about tornadoes. 14:50 This concept that if a tornado hits a major metropolitan area, 14:54 the potential for death and destruction is tremendous 14:59 and I don't think we really spend much time thinking about that as a possibility. 15:04 So, how we prepare for that in the future is a challenge for urban areas 15:09 but that is a real issue for almost every city in the Eastern United States, I'd say. 15:14 Absolutely. 15:16 Thank you. 15:17 All right. Thanks.