Year of the Twisters: 2011 and its Tornadoes

After news of the Joplin, MO tornado—which killed at least 89 people and carved a mile-wide rut through the town—I started thinking about how remarkably active this tornado season has been.  We are way, way above the ten-year average for this time of year, both in terms of the raw number of tornadoes as well as tornado deaths.

Dr. Greg Forbes at Weather.com has written us a brief summary of these statistics (with two nice graphs) that I highly recommend reading.  We're already in the midst of the deadliest tornado season since 1953, and we've logged two of the ten deadliest tornado days in U.S. history during 2011.

Forbes mentions that forecasting and severe weather warning systems have come a long way over the course of a few decades; and he cites tornadoes hitting larger population centers this year as the primary reason for the high number of fatalities.  But I have to think the tornadoes that have hit larger cities like Birmingham have also generally been more powerful.  In 2010, we saw fourteen EF4 twisters and no EF5's.  The April outbreak alone produced eleven EF4's and three EF5's—in three days.  (These numbers are still preliminary while NOAA continues to assess storm damage and data, but we're not even through the most active month yet.)  Sixty years ago, there was no alert system, so it's understandable that a tornado could hit without much warning and claim the lives of people who were simply unprepared.  However, residents of Alabama had a 20-minute lead time during the April 2011 outbreak: most of them had probably taken shelter and were indoors on the lowest  floor of their home or in a basement somewhere.  When an EF5 hits, though, there's no escape.

During the past eleven years (2000-2010) about 18 people died per year, on average, in a permanent home as a result of a tornado.  Unsurprisingly, the majority of deaths each year occur in mobile homes or vehicles.  In 2011, 65 people have died already in permanent homes with the circumstances of another 159 deaths (more now because of the Joplin storm) yet to be determined.  That's 3.6 times the typical number of home deaths for an entire year that we've tallied in less than five months, and more than 340 people have died in all so far this year.

I'm probably more terrified of tornadoes than your average person.  And while the vast majority of tornadoes are small EF0 and EF1 events for which taking cover will usually suffice, standing in the face of anything EF2 or higher is a fool's game; plus, unless you're looking at an obvious behemoth, you won't know until after the fact how strong a storm you're dealing with.

Better safe than sorry.

(Mashable has posted a list of ways in which you can help the victims of these storms.)

[UPDATE] May 23, 2011: The death count for the Joplin tornado is now at 116.


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