Story Highlights

  • 2013 national year-to-date tornado totals down from 30-year average

  • Colder spring air may be one reason for current tornado drought

  • Research continues into how climate change will affect tornadoes

Climate Research

A new report released by Climate Central this week on the six-month anniversary of Hurricane Sandy reveals that storm-surge flooding of treatment facilities sent 11 billion gallons of sewage into rivers, canals and city streets.

This Week in Climate News

Meet GROVER: NASA’s New Ice-Loving, Roving Robot

Heeding Sandy’s Lessons Before the Next Big Storm

Wild Weather Swings May Be a Sign of Climate Change

Tweetable Fact

Tornado Drought: YTD 2013 tornado count down 54% compared to 30-yr avg.

The Archives

Click here to see past issues for each participating market.

For More Information

Contact Us:

Click here for a high-resolution version

Drought is a bad thing — unless you’re talking about a tornado drought. That was the situation in 2012, when the number of twisters touching down in the continental U.S. was significantly fewer than the 30-year average (red). So far, 2013 (green) is looking pretty sparse as well, with the caveat that states in northern sections of Tornado Alley don't hit their storm stride until later in the spring and summer. Still, other than a few specific areas, the nationwide January through April tornado count is way down, 54 percent to be exact.

Pinpointing the reason for tornado droughts (and deluges) isn’t always easy. Last year’s drought — the actual drought that devastated much of the Great Plains — robbed the atmosphere of the water vapor that fuels severe thunderstorms. Since tornadoes come from thunderstorms, this key thunderstorm ingredient was missing.

This year, while the drought is still going on, it’s much less severe — yet we may be seeing another tornado drought in the making. This time, it may be the relatively cool spring air much of the nation has been experiencing. Heat is another key ingredient of thunderstorms.

As for 2014 and beyond, it’s natural to wonder if climate change will make tornado activity more or less severe as the planet continues to warm. The answer is not clear. Since tornadoes play out in the atmosphere, it’s likely that a changing climate will also change tornado activity. But tornadoes are complicated beasts, affected not only by moisture and temperature but also by wind shear and other factors. So far, there’s simply not enough information to say anything definitive about the future of tornadoes under global warming — but that, too, will change in coming years.

Click here for a high-resolution version

      Related videos:

Extreme Weather 101: Tornadoes
Tell Me Why: Questions Swirl Around Tornadoes and Climate
How Do We Know: Tracking Tornadoes
Embeddable Tornado Tracker

View this email in your browser | Unsubscribe from this list