The havoc wrought by a tornado in instants often requires days to assess. It’s necessary to examine damage across wide regions where roads, bridges and infrastructure are often wiped out. Eventually disaster and relief officials use aerial photos.
Tom Lillesand: All that takes a lot of effort and a lot of time. . .
Tom Lillesand is director of the University of Wisconsin’s Environmental Remote Sensing Center in Madison. He used Landsat 7 satellite data to help disaster officials when a violent twister struck Wisconsin in June of 2001.
Tom Lillesand: . . . and it’s hard when you have an event that’s 41 kilometers long and half a mile wide in locations — to even do it using aerial photography. It took us over, some 300 photographs to cover the same area that was just a very small portion of a single Landsat scene. . .
With the help of the Landsat 7 satellite, Lillesand and his team produced detailed images and maps of the tornado impact zone. These were ready to send to emergency teams in just six hours. In April of last year, researchers again used Landsat data to pinpoint damage from a tornado in Maryland.
Lillesand would like to see this technique become a standard part of relief efforts.
On April 28, 2002, an F4 tornado (downgraded from an original F5 estimate) hit La Plata, Maryland. Tim Olsen, also at the University of Wisconsin’s ERSC, studied damage from this tornado that hit just south of the U.S. capital. Their assessment wasn’t as successful as the assessment of the Siren, Wisconsin tornado the previous year. That’s becasue the land was different — it was more agricultural land and a different soil type, but it was still possible to use Landsat to do that.
The ERSC team haven’t done anything formally to do more of this technique in the future. According to Tom Lillesand, “We don’t have funding to do more work like this. We’ve only used Landsat for these analyses because it has the best spatial resolution, relative to other satellites.”