Storm survey teams with the National Weather Service look at damage left behind by a tornado to estimate the strength of its winds. The EF Scale ranges from zero to five, with five indicating winds of 200 mph or greater.
Chris Nuttall is the Warning Coordination Meteorologist at the National Weather Service in Shreveport, LA. "We have a list of 28 different damage indicators [ranging] anywhere from hardwood and softwood trees to manufactured homes to single family homes, small retail buildings, metal warehouses, electrical transmission lines. There's a whole list of them," he tells AFN.
Tony Lyza with NOAA's National Severe Storms Laboratory in Norman, OK, told Fox Weather that he and other researchers studied 105 tornadoes that passed close to NWS radar sites.
"And what we ended up finding was that consistently, no matter where the tornadoes occurred or how built up those areas were, the wind speeds tended to be higher based on estimates from radar," he explained.
A variety of radar sites were sampled. "Our study looks at not only tornadoes that occurred on the Great Plains, but anywhere in the country where a tornado passed close to a weather service radar," said Lyza. "So, we could compare [speeds of damage] over forested areas, over hilly areas, over more populated areas" versus what the radar was measuring.
He said understanding the strength of tornadoes will help in knowing how strong homes and offices need to be.
