Wednesday April 27 was the deadliest tornado day in the United States at least since April 3, 1974, when 308 people lost their lives. The death toll for Wednesday’s event is still rising; it stands at more than 300 at this writing (April 29, 2011, 17:00 GMT).
Here are some sources that we at EarthSky trust and use:
Kristina Pydynowski at Accuweather: First EF-5 Tornado Declared in Wednesday’s Horrific Outbreak
Jeff Masters of Weather Underground: Over 300 dead in historic tornado outbreak; one violent EF-5 tornado confirmed
Is there a connection between the tragic weather events of this week, and global warming? Probably not, experts say. While raw reports of tornadoes have doubled in the U.S. since the 1950s, this trend may primarily reflect the increase in number of people living in tornado-prone areas, leading to more tornado sightings. That’s in contrast to “a real increase in the occurrences of tornadoes,” according to a 2008 report by NOAA titled Weather and Climate Extremes in a Changing Climate.
The report added:
There is no evidence for a change in the severity of tornadoes and severe thunderstorms, and the large changes in the overall number of reports make it impossible to detect if meteorological changes have occurred.
Thus, although an increase in severe weather is a prediction of global warming, no solid evidence of this increase existed as of 2008, and there are reasons to think tornadoes will not increase in number or severity as climate warms. See the following two posts for good explanations:
Andrew Revkin at New York Times’ Dot Earth blog: Killer Tornadoes, Horrible and Still Unknowable
Andrew Freedman at ClimateCentral: Tornado Outbreak Raises Climate Change Questions
Here’s more on the type of extreme weather we can expect, in the years ahead.
Deborah Byrd created the EarthSky radio series in 1991 and founded EarthSky.org in 1994. Today, she serves as Editor-in-Chief of this website. She has won a galaxy of awards from the broadcasting and science communities, including having an asteroid named 3505 Byrd in her honor. A science communicator and educator since 1976, Byrd believes in science as a force for good in the world and a vital tool for the 21st century. "Being an EarthSky editor is like hosting a big global party for cool nature-lovers," she says.