A major spring storm system swept across the United States, leaving a swath of devastation from the Great Plains to the East Coast. Powerful tornadoes caused numerous deaths in the Plains and the central Mississippi Valley. This pair of visualizations shows rain rate data collected by the Tropical Rainfall Measuring Mission (TRMM) satellite on May 11, 2008, at 04:00 UTC (May 10 at 11 p.m Central Time) and 05:38 UTC (May 11 at 12:38 a.m.). Rainfall intensity ranges from blue (light rain) to red (heaviest rain). Patches of intense rain stretch out in a southwest-northeast line of storms.
At the time of the first of these two TRMM passes, a tornado was reported in Laurendale County in the far northwestern tip of Alabama. TRMM shows the responsible thunderstorm cell has very intense rain (dark red area) associated with it. The tornado was later reported to be an EF1 by the National Weather Service. Additional tornadoes were reported in north central and northwestern Alabama not long thereafter. As the overall storm system advanced eastward, so too did the focus for severe weather.
In an average year, roughly 60 people are killed by tornadoes in the US each year. As of May 11 2008, 98 deaths had already been attributed to tornadoes. More than 900 tornadoes had been recorded by early May, a total that in most years is not reached until August.
The TRMM satellite was placed into service in November 1997. From its low-earth orbit, TRMM provides valuable images and information on storm systems around the tropics using a combination of passive microwave and active radar sensors, including the first precipitation radar in space. TRMM is a joint mission between NASA and the Japanese space agency, JAXA.