Tornado forming: Book of Odds Talks with Storm Chaser Joshua Wurman

The odds a person will be killed by a tornado in a year are 1 in 4,513,000.

It’s not at all likely you will be killed by a tornado. Or as Dr. Joshua Wurman puts it: “Suicide by tornado would be very inefficient.”

Wurman is so confident he will survive an up-close encounter with a tornado, he has spent nearly 15 years chasing them all over the world. In his opinion, “People dread tornadoes out of proportion to the actual probability that they will happen.”

In the lab and on the ground, Wurman is one of the country’s leading tornado experts. It was Wurman who developed Doppler on Wheels (DOW) radar technology, and he is credited with capturing the highest wind speed ever recorded in a tornado—301 mph. His team has been featured on the Discovery Channel’s Storm Chasers, but even Wurman can be fooled by Mother Nature.

“Most storms we intercept don’t turn into tornadoes. And we really don’t have great skill in knowing which ones are going to, so we chase after a lot of them. Only a few pay off.”

To date, Wurman has collected data from more than 140 tornadoes. “The prize is not only getting the data, it’s learning from that data. We’re trying to understand as much as we can, not only about the wind speed, but also the temperatures and the relative humidity in and around tornadoes.”

Most of the year he spends in the lab. But when the peak tornado months of May and June come around, Wurman’s team sets out. Last spring, Wurman spent five weeks chasing storms as one of the leading scientists involved with the largest tornado research project to date: VORTEX2.

Tornado Season 2009 turned out to have many quirks. “We were kinda shut out in the first three weeks. There were hardly any storms, never mind tornadoes.”

They observed only one tornado. But what a tornado it was. “That particular tornado was by far the best-studied tornado ever. That was a platinum-plated, diamond-encrusted data set! The tornado lasted 30 minutes, and we’ll be looking at that data for 30 months.”

When the spring storms finally kicked up, the teams had to constantly adjust their pace. “Storm chasing is a lot of shifting, jockeying for positions. We start out the morning in a hotel somewhere, waking up around 10 AM. We’d do weather briefings and discuss where we think the target area’s going to be. Sometimes it was, ‘Oops, you know, the storm’s really going to form out in Colorado, and we have to drive six hours to get there!’ We’d scramble to leave right away.”

Frantic activity is interspersed with long stretches of downtime with little to do. “We’d be in a Wal-Mart parking lot for two or three hours, or maybe a gas station.” Waiting for a storm to take shape, “We like to be where there’s at least some junk food and a bathroom.” With his large crew, there is always the issue of logistics: getting everyone fed, and the vehicles fueled. “Imagine 160 hungry people showing up in one of these small, one-gas station towns.”

When they think a storm is about to “pop,” they make a quick decision to try and intercept the storm. But it’s easy to get lost.

“Every minute we’re watching the tornado change and looking at it with multiple radars. We’re surrounding the tornado with weather instruments mounted on cars and on tornado pods that we drop in front of the tornado.”

“Our entropy increases with time. We just get more random in our deployment.”

They hope that the data they collect will help develop better forecasting strategies. As it stands now, Wurman identifies three major issues with tornado prediction.

Timing: “Warnings don’t have enough lead-time. The average lead-time is 13 minutes, which means that half of those warnings are happening with less than 13 minutes. What’d we’d like is to give people a half hour to an hour of lead time ahead of the storm.

Accuracy: “There’s 70% false alarm rate associated with warnings. So do you really head to your basement? Do you really wake up your kids and have everybody screaming and ruining your evening?”

Precision: “It isn’t an official National Weather Service goal, but I think we need to get warnings more precise, telling us whether or not a really violent tornado is coming our way.” He compares it to hurricane warnings. “When a hurricane’s coming and you’re told it’s a 1, put some plywood on and stay home. If it’s a category 5, everybody below 30 feet in the coastal areas better evacuate.”

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