Tornadoes getting stronger Some of the most provocative research presented at the #AGU13 meeting thi

Tornadoes getting stronger Some of the most provocative research presented at the #AGU13 meeting this week in San Francisco came from Dr. James Elsner (@hurricanejim). His claim is a pretty startling one; Tornadoes in the U.S. are getting stronger. There are many ways to measure the intensity of tornadoes; their length, their wind speed, and the number of them. Traditionally, people have focused on the last item, the number of tornadoes per year. That number has gone up, but at the same time the U.S. weather service has gotten much better at isolating tornadoes, so that may not tell us about actual changes in the weather. The weather service also has gotten better at categorizing the intensity using the EF-scale, making it hard to say whether there are more strong tornadoes per year from that data. Instead, Dr. Elsner tried a different method to look at tornado impacts. Since the 1980’s, the U.S. has been covered quite well by weather radar that picks up signals from tornadoes including wind speeds and intensities. By combining data from weather radar with information on the length of tornado damage paths…a startling trend appeared. Tornadoes in the U.S., particularly since the year 2000, are lasting longer, getting bigger, and are more energetic, more intense. Dr. Elsner stresses that these are preliminary results, with a lot of explanations. For example, it’s possible that he could be seeing a signal of weather migration – storms that used to hit Canada instead hitting the U.S. Of course, the other obvious answer is that he’s seeing a direct result of climate change on tornado intensities. More research needs to be done on this trend. The data is brand new, but this data is actually more accurate than the data which characterize hurricanes, for example, since it comes from within the country I’ve previously been skeptical of claims about the impact of climate change on tornadoes because we didn’t have high quality data to support those claims. The data Dr. Elsner presented is the type of high-quality data we needed, taking into account how measurement types have changed over time. This should be a worrisome data set and should drive a whole lot of additional research, because increasing tornado intensities with time would be a terrible thing, hurting a lot of people. -JBB Image credit: http://commons.wikimedia.org/wiki/File:F5_tornado_Elie_Manitoba_2007.jpghttps://twitter.com/climatebrad/status/410888839121477633/photo/1http://blog.environmentalresearchweb.org/2013/12/12/agu-2013-are-tornadoes-getting-stronger/ -- source link

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