Tag Archives: tornado

Ten years since Jamestown

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Ten years ago, I was sitting in my apartment on a rainy Tuesday afternoon. My last class of the day ended around 1:30 and I was settled in to get some work done on the forecast game that I ran for the University. WFO Lincoln had issued a few tornado warnings and there were reports of cold air funnels, so my friend Mike Kruze and I decided to spend the afternoon driving around getting rained on. Instead, we saw one of the most photogenic tornadoes ever recorded in Indiana. And then another one. And then a third (though this one is unofficial, since we could not see the ground from our position and no damage was observed in the empty field).

This was only two days after Mike and I had returned from a marathon drive to northern Iowa, where the most we saw was vivid lightning and large hail after sunset. By this point, I had been chasing for a year and a half. Chase attempts evolved from some undergrad doofuses piling in the car and driving around to a fairly mature venture with thoughtful forecasts, data stops, and real efforts to be in position. Of course, as luck would have it, April 20 ended up being somewhat of a doofus day. Mike had a data plan on his Sprint PCS phone, and it was just enough for us to pull up the occasional radar image. Without that, we’d never have found ourselves standing in rural Boone County with a tornado directly to our west.

At the time of the Jamestown tornado, FunnelFiasco.com wasn’t even a gleam in my eye. I was planning on making a career in the National Weather Service. I figured chasing would be a thing I did with regularity. Ten years on, I’ve earned my meteorology degree, but I’ve never worked as a professional in the field. I have one chase day in the last five years, and I’m less than a year from a decade-long tornado drought. I’ve still only chased west of the Mississippi twice. With a toddler and home and another baby due early summer, I’m not likely to get out this year. But I still feel the gentle tug of the storm, pulling me to go out and seek it. I know I will at some point. I just don’t know when.

Thoughts on the Weather Forecasting Improvement Act

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Insurance Journal reported last week on a bill sponsored by Representative Jim Bridenstine (R-Oklahoma). In a fit of poor reporting, the author says the bill makes the “protection of people and property a priority.” Unfortunately, the National Weather Service mission statement has included “protection of life and property” for years. The bill itself contains no such insulting verbiage. On the surface, it’s actually a welcome relief: a Congressman looking to direct over half a billion dollars of new funding to scientific research and operations. In reality, it strikes me as more of a pipe dream.

The average tornado warning lead time is currently around 13 minutes. The goal of Bridenstine’s bill is a lead time of 60 minutes or more. Stretch goals are good, but a 4x increase is not, perhaps, the most appropriate for legislation. Even so, there’s a question of how valuable such an increase would really be. Increased protection of property is probably not going to be that dramatic with hour-long lead times. It’s not like people can move their houses and businesses out of the way. Some damage could be prevented by securing loose objects and boarding windows, but it’s not likely to be significant.

Protecting life is the more important aspect, but would a one-hour lead time help? I’ve argued for years that there’s definitely an upper bound to lead times after which the returns diminish. My suspicion is that as the lead time grows beyond that point, people become more and more complacent. This argument has been based on hunches and unsubstantiated reasoning. It turns out, there’s evidence that increased lead time has no impact on injuries from tornadoes.

Even if the benefits are minimal, the amount of learning that would have to take place to get lead times up to an hour would aid our understanding of severe weather. The improvements to observation networks and modeling would benefit all areas of weather forecasting. Even  if tornado warning lead times remain unchanged, the scientific impact of this bill would be dramatic. I just worry that it’s setting the National Weather Service up for “failure”.

2013 severe weather watches

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Greg Carbin, Warning Coordination Meteorologist at the Storm Prediction Center, recently updated his website to include maps of 2013 severe thunderstorm and tornado watches. I always like looking at these, because they highlight areas of increased and diminished severe weather threat. It’s important to not read too much into them though. As with hurricanes, it’s not always the frequency of events that makes a year memorable. 2013 was a below- or near-normal year for watches in the areas of Illinois and Indiana that were hit by a major tornado outbreak on November 17.

Tornado (left) and severe thunderstorm (right) watch count (top) and difference from 20 year average (bottom) by county. Maps are by the NOAA Storm Prediction Center and in the public domain.

Speaking of hurricanes, the quietness of the 2013 Atlantic hurricane season is evident in the below-average tornado watch count along the entire Gulf coast. Landfalling hurricanes are a major source of tornado watches for coastal states, so an anomaly in watches is often reflective of an anomaly in tropical activity. Preliminary tornado counts for 2013 are the lowest (detrended) on record. It’s not surprising, then, that the combined severe thunderstorm and tornado watch counts are generally below normal.

Severe weather watches (left) and departure from normal (right) by county. Maps are by the NOAA Storm Prediction Center and are in the public domain.

As you’d expect, Oklahoma and Kansas had the largest number of watches. What’s really interesting about the above map is the anomalously large number of watches in western South Dakota, western Montana, and Maine. Indeed, western South Dakota counties are comparable to Kansas in terms of raw watch count. Of course, that doesn’t mean the watches verified, but it’s an interesting note. Looking back through past years, the last 4 years have been anomalously high in western South Dakota. Is this an indication of a population increase, forecaster bias, or a change in severe weather climatology?

Reflecting on my tornado response

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A week ago, a large tornado outbreak struck the Midwest. In Indiana alone, 28 tornadoes caused considerable damage. Fortunately, the outbreak was well-forecast, and the human toll was much lower than for other similar events. I’m not going to review the synoptic conditions here, because this isn’t about the weather, per se, but how I handled it.

Map of central Indiana tornado tracks. Produced by the National Weather Service in Indianapolis.

Map of central Indiana tornado tracks. Produced by the National Weather Service in Indianapolis.

My friends Kevin and Colleen were visiting. Kevin is also a storm chaser, so shortly after they arrived he and I were on the couch with our laptops, watching a line approach us from the west. The first indications that the forecast would verify were the startling images from Washington, Illinois. The early pictures of the damage left no doubt that the environment would support violent tornadoes.

By early afternoon, it was time for my daughter to take her nap. My wife took her upstairs and the adults sat downstairs and socialized. And watched radar. As the line approached, several areas of concern presented themselves. Kevin and I considered a trip north to Fowler, but decided that with the speed the line was moving, we’d have a hard time intercepting it. The linear nature of the storms made visibility and escape real concerns as well. Around that time, I noticed another area of rotation around Interstate 74 near the Illinois/Indiana line. I remarked that it was heading for us, so that was another good reason not to go after something else.

As the 3:00 hour approached, it was evident that the rotation really was heading toward us, and I suggested that we should put our shoes on in anticipation of seeking shelter in the basement. When the rotation crossed into Tippecanoe County, I determined that it would pass safely south of us, but I was concerned about our friends on the south side of Lafayette. I let them know to get to their basement immediately. Around that time, Kevin went to stand on the front porch.

The rain began, and the wind picked up. At approximately 2:52 PM, the wind speed picked up dramatically. I estimated the gusts to be 80 miles per hour. Kevin came running in from the porch and said we needed to get to the basement right away. My wife was already on her way upstairs to grab my still-sleeping daughter. A few seconds later, we were all downstairs. Kevin had seen a sudden shift in wind direction, and the blowing leaves lifting up made him wonder if we had just been tornadoed. I began to wonder if I had made an error in judgment.

After a couple of minutes, we went back upstairs. The power had gone out before we went to the basement and it remained off (it would be about 39 hours before power was restored to my house). I went outside to survey the damage and was pleasantly surprised to see none. Four and a half miles to the south, it was a different story. NWS damage surveys would show that an EF-3 tornado had carved a 29-mile path across three counties, causing major damage to two area manufacturing facilities.

After an event like this, it’s natural (and appropriate) to look back and see what went right and wrong. Before the storms arrived, we had packed a diaper bag and brought it downstairs. We constantly monitored the weather conditions. I correctly judged that we were not threatened by the tornado. What I did wrong was I focused solely on the tornado threat. With the line moving at 70 mph, the wind threat was considerable. Although it didn’t cause any damage at our house, an 80 mph wind gust is not something to take lightly. My timing was okay, but in retrospect, I’d rather have pulled the trigger a minute sooner to make our trip to the basement more controlled. Even though we were well-prepared, the execution was still uncomfortably rushed. The balance between minimal disruption and safety is sometimes hard to make.

 

KIND radial velocity image from 1952Z on November 17. The area of rotation (circled) is moving northeast. The X roughly approximates the location of my house.

KIND radial velocity image from 1952Z on November 17. The area of rotation (circled) is moving northeast. The X roughly approximates the location of my house.

Remembering Tim Samaras

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I woke up this morning to learn that veteran tornado researcher and storm chaser Tim Samaras and two others were killed by a tornado near El Reno, Oklahoma. I never knew Tim in person, but I had the pleasure of interacting with him on the wx-chase mailing list and on the Stormtrack forum. Tim was of the old breed of chasers: safety-conscious, focused, and a serious scientist. This makes his death all the more jarring; Tim Samaras is about the last person you’d expect to die in a tornado.

That’s why this is so upsetting for me. I’ve always held to the belief that chasers are safe so long as they’re not stupid. I don’t know what happened in those last minutes, but it’s safe to say Tim was not being stupid. Did he make a mistake? Did he lose situational awareness? Was this a completely unavoidable accident? I can’t answer any of these, which means I’m face-to-face with the lethality of my sometimes-hobby.

To my knowledge, Tim and his companions are the first people to die while actively chasing. The other deaths that I’m aware of were due to roadway accidents on the drive home. That nobody has been killed is a surprise in itself given some of the crazy antics of those who have taken up the hobby inspired by “Twister” or Discovery’s “Storm Chasers”.

Tim can no longer contribute to the scientific study of tornadoes. Perhaps his death will serve to remind us all that even the best are vulnerable.

Tornado safety in schools

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Yesterday afternoon, the second EF-5 tornado in 15 years struck the town of Moore, Oklahoma. As a nationwide audience watched the live coverage from local TV station, the tornado leveled roughly 30 square miles, including two schools, plus damage to three more and to a hospital. I don’t know what it is about Moore, but it seems to be a tornado magnet.

Historical tornado tracks (colored by intensity) from tornadohistoryproject.org. This does not include the 2013 EF-5.

Historical tornado tracks (colored by intensity) from tornadohistoryproject.org. This does not include the 2013 EF-5.

From what I’ve read, the school day had not yet ended when the tornado struck, which meant the schools were full. As the immediate shock wears off, some of the discussion will inevitably turn to the question of whether the schools should have dismissed early. In my opinion, the answer is “absolutely not”.

While it’s true that (as of this writing) nine children died, it’s quite possible the death toll would have been even worse. If the students don’t get home before they tornado hits, they’re sitting ducks in the school bus or walking home. During last year’s Henryville, IN tornado, a bus driver returned to school after an early dismissal, saving the lives of the students aboard.

Even if the students make it home, that’s not necessarily much safer. Numerous homes in the damage path were leveled. In other cases, students live in mobile homes or otherwise weak structures. It is tantamount to a death sentence to send them home in such conditions. This was the case in Enterprise, Alabama in 2007. While school officials received criticism for this decision, they made the right one.

Having students on the road during a tornado is obviously not the answer. Having students at be home isn’t particularly compelling in many cases. Because we cannot yet predict the specific path of a tornado until it has formed, it’s hard to make the argument in favor of cancelling classes. While some students have been killed by staying at school, it remains the best option available.

Outdoor warning sirens

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After adding my last post to Google Plus, a friend asked my thoughts on tornado sirens. I replied that I thought they provided a rather poor return on investment. This eventually lead to a day-long discussion with a coworker who disagrees with my assessment. Since I’ve never put my opinion on sirens in a blog post, I figure it’s time to do just that.

First, I am of the opinion that sirens serve an important role in public safety. In places like parks, golf courses, and common outdoor gathering areas, sirens are an excellent way of communicating a single message: “seek shelter”. Sirens are unable to communicate why shelter should be sought, when it is safe to come out (though some jurisdictions will re-sound sirens as an all clear), or what the threat is. Some siren systems lack battery backup, occasionally rendering them inoperable at the most inopportune times. Sirens also suffer, as do most alerting systems, of being stuck in a county-based warning system that no longer exists.

Although they are not intended to be indoor warning devices, some people still rely on them as their primary means of receiving severe weather alerts. When close enough to a siren, this can be fairly reliable, but it’s not always the case. My house is 1000 feet from the nearest siren and during tests it is quite audible (uncomfortably so when the windows are open). During heavy rain, it is not nearly as noticeable. I have little doubt that I would sleep through an overnight siren sounding if it happened during a heavy rain.

So what, then? Since the 1970’s, NOAA Weather Radio has served the country well. It provides both alerts and routine weather information around the clock. Unfortunately, it’s also stuck in the 20th century. County-based alerting simply cannot continue to dominate our warning dissemination systems. If the weather radio system were to send warning coordinates along with SAME codes, receivers could optionally determine if the alert needs to be sounded. In addition, most counties are served by a single transmitter. Each transmitter should have a redundant backup, located far enough away to be unlikely to fail from the same event (e.g. power outage, tornado), but still able to cover the assigned counties.

The current state of sirens in Tippecanoe County includes coverage of all areas I propose require it (and probably some that don’t). There are still, by my calculations (see note 1), approximately 25,000 people in the county who live outside the audible range of sirens. In order to cover the entire county’s land area, the initial investment would be $960,000 to $2.7 million (see note 2) with an annual maintenance cost of $115,200-324,000. (see note 3)

I wanted to look at the costs for all thirteen counties served by the WXK74 transmitter in Monticello, but it turns out the siren count information is not easy to find. WTHR in Indianapolis did some of the work for me, but the rest had to be independently researched. Sadly, some Emergency Managers don’t want to disclose even a count of the sirens in their county. As a result, I was only able to obtain authoritative siren counts for Cass, Clinton, Howard, and Tippecanoe Counties.

Using the same strategy as for Tippecanoe County, I calculated what it would take to get these four counties to 100% siren coverage. The recurring costs are $774,00 to $1.44 million. This after an initial investment of $6.42-12 million dollars. And remember, that’s just for four of the fourteen counties, only 30% of the land area covered by WXK74 (roughly 65% of the population).

What would happen if instead of sirens, we added a second transmitter site and bought every household in the covered area a $50 weather radio? The cost of the transmitter would be about $75,000 (see note 4). Buying the radios would bring the cost up to roughly $9.84 million, which is in the range of covering 65% of residents with sirens.

Of course, this is entirely academic. Sirens are funded at the county level, whereas weather radio is a federal project. It’s not easy to just move the money around. There’s also the alert-granularity issue that needs to be resolved.

Given the economics and the richness of information, it makes sense to push for more radios instead of more sirens. Sirens have their place, but those places are limited. The Indiana Department of Homeland Security guidelines would suggest that many local cities and towns should not have sirens at all (except for parks). Ultimately, weather alerting requires a defense-in-depth approach. Sirens are one layer in certain situations. Weather radios are another, more broadly applicable layer.

A third layer is the Wireless Emergency Alert (WEA) system that is being deployed. Unfortunately, it requires a relatively modern smart phone, so I expect the penetration rate is still fairly low. It, too, suffers from a lack of geographic granularity (although probably better than either weather radio or sirens), and sparseness of information (WEA messages are limited to 90 characters). There’s also people who don’t have their phone by their side at all times. Some people actually leave their mobile devices in other rooms sometimes? Quelle horreur! Disturbingly, WEA does not interrupt phone calls, meaning a long gab session will result in you receiving a warning after it has expired.

Given budgets and politics at all levels of government these days, I’m sad to say that I don’t see any of the existing deficiencies being resolved any time soon.

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More thoughts on warning polygons

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On Tuesday, Patrick Marsh wanted a distraction from his dissertation and embarked on an idle investigation of tornado warnings and impacted areas (my thoughts on what “impact” means are below). Using some very rough approximations, he calculated the percentage of warned persons who are impacted by a tornado. Even under the most generous set of assumptions, the verification by population is generally below 20%. It’s worth noting that 2011 (the most recent year that official tornado data is available) was the best year in the analysis, but there is no indication of a general improvement trend.

Despite some of the problems I’ve previously noted in the polygon warning system, it’s still better than warning entire counties. Still there’s a lot of room to improve the false alarm rate. Much of the population-based false alarm comes from warnings that have no tornado at all. The rest either comes from too-large warnings or not-small-enough warnings (“not-small-enough” warnings are small enough to be justifiable, but still larger than absolutely necessary).

It’s not always easy to shrink warnings. Only the supercell storms relatively close to a radar site seem suitable. In those cases, it’s possible to make the warning only a few miles wide, or the width of the mesocyclone with uncertainty added as you go downstream. This would minimize the area under the warning, but it got me wondering: would that be too small?

At the scale of a mile or two, how do you explain the warned area to the public? Storm-based warnings are already difficult to communicate quickly, and microwarnings would only compound the problem. Even in Lafayette, the 10th largest city in Indiana, the covered area might look something like:

...TEAL ROAD BETWEEN 4TH STREET AND 26TH ST...
...KOSSUTH ST BETWEEN 9TH STREET AND SAGAMORE PARKWAY...
...SOUTH ST BETWEEN FIVE POINTS AND FARABEE DR...
...18TH ST BETWEEN BECK LN AND FERRY ST...

And so on. Or maybe it would use neighborhoods and landmarks instead:

...LAFAYETTE COUNTRY CLUB...
...HIGHLAND PARK...
...JEFFERSON HIGH SCHOOL...
...FIVE POINTS...
...WALLACE TRIANGLE...
...COLUMBIAN PARK...

Either way, it’s much more complicated than a simple “LAFAYETTE”. Yes, it’s more detailed, does that help? First, it takes much longer to read the text. Secondly, can you count on people, especially those who are new to the area, to know the streets, neighborhoods, and landmarks well enough to quickly figure out if they’re affected or not? I suspect the answer is “no”.  Perhaps some day someone with the time, energy, and funding can look at this.

Sidebar: What does it mean to be “affected” by a tornado?

When Patrick commented on Twitter about his post from Tuesday, I remarked that the results depend on how “affected” is defined. His analysis was based on population, but that doesn’t necessarily convey all impacts. If my office is wiped out by a tornado but my house is untouched, I am still affected. You can expand this out even further and incorporate businesses that saw decreased revenue as a result of a tornado, even if they were not directly hit. Businesses that see increased revenue (e.g. home improvement stores) might also be included, even though the effect is a positive one. The broader (and, I would argue, more accurately) we define being affected, the more difficult it becomes to get accurate data.

Increased complacency about severe weather benefits no one

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The number of meteorologists in the United States is very small.  According to the Bureau of Labor Statistics, less than 10,000 people are employed as atmospheric scientists in non-faculty positions (anecdotal evidence suggests that the number of people holding meteorology degrees is significantly higher. To wit: of the 12 people in my graduating class, four are meteorologists).  With such a tiny fraction of the population trained in atmospheric science generally, and severe storm meteorology specifically, it should come as no surprise that the public knows relatively little about severe weather.  With the small number of meteorologists, a heavy reliance is placed upon the media and local officials to convey information.

However, while the media and local officials may get more exposure to weather information, they do not necessarily understand it any better than the rest of the general public.  This leads to newspapers reporting that a “local tornado warning was issued” (only the National Weather Service issues tornado warnings officially, and causing confusion about this does not help the public interest) after a “funnel cloud on the ground” was sighted (a “funnel cloud on the ground” is more properly known as a “tornado”, but in this case it was more likely a mere “scary-looking cloud”). It leads to emergency managers sounding warning sirens when the greatest threat is heavy rain and sub-severe winds.  And it leads to confusion and eventual complacency for the public.

Meteorologists have enough trouble fighting complacency as it is.  The most recent data from the National Weather Service indicates that 76% of tornado warnings are false alarms.  This is not because of incompetent meteorologists.  It is a limitation of available observation systems (radar), of the understanding of tornadogenesis, and of the (quite reasonable) belief that it’s better to overwarn than to miss a tornado.  Additionally, since tornadoes are often relatively small and short-lived events, it may be that some of these false alarms are not so, but there are no reports thus the warning remains unverified.  The upshot of all of this is that it’s very easy for the public to not take warnings seriously.

I can, perhaps, understand the reason the Tippecanoe County Emergency Management Agency (TEMA) decided to sound the sirens last Saturday.  A street festival was about to begin in downtown Lafayette, and many people were moseying down Main Street.  The wind and rain had already begun clearing the streets before the sirens sounded, and no one seemed to be in any additional hurry when they heard the beautiful wail.  It can argued that the sirens were sounded appropriately in that case, but the public mindset is that the sirens are “tornado sirens”, so sounding them for non-tornadic events (especially events that posed such a dubious threat) does a disservice to the public because it increases complacency.  In this specific case, the sirens added nothing helpful, and thus should have remained silent.

Were this an isolated incident, I would not have felt compelled to write this post, but TEMA during the Mark Kirby era has been quick to sound the sirens.  In my circle of meteorological friends, there are two common consequences to rainfall: 1) the Indianapolis radar goes out of service, and 2) the tornado sirens are sounded in Tippecanoe County.  If I’ve associated the sirens with rainfall, surely there are others in the county who have done so as well.  So who benefits from sounding the sirens so much? No one.