Sources of information for deadly tornado outbreak in southern U.S.

With more than 300 dead and the death toll still rising, April 27, 2011 ranks as one of the nation’s deadliest tornado days.

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).

A tornado moves through Tuscaloosa, Ala., on Wednesday, April 27, 2011. (AP / The Tuscaloosa News, Dusty Compton)

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.

Thomas Karl connects extreme weather and climate change

Deborah Byrd