Published March 26, 2012
With 1,706 confirmed tornadoes that took 550 lives, almost as many deaths as the prior decade combined, 2011 was an exceptionally destructive and deadly year. The National Weather Service hopes new radar upgrades will better predict severe weather this year -- and save lives.
The new dual-polarization technology installed at the National Weather Service office in Huntsville, Ala., last December was key in issuing warnings when a line of severe storms spawned six tornadoes on the morning of March 2. Dave Nadler, the warning-coordination meteorologist for northern Alabama, says the new equipment and software allowed weather service officials to get tornado warnings out faster and more accurately.
“We wanted to make sure that we were saying, okay, at this point there is a tornado on the ground. Possibly a strong tornado given this debris signature,” Nadler told Fox News.
Current radar technology sends out horizontal sweeps, sending back one-dimensional images of clouds, rain, hail and snow. The new dual-polarization sweep uses horizontal and vertical beams, giving forecasters a two-dimensional look at severe weather. During the tornado outbreak March 2, it picked up images of the "debris ball" -- actual pieces of buildings and trees being tossed around.
“The biggest thing with the tornado situation was confirmation of that debris ball or debris signature from something that was on the ground,” Nadler said. “It was lofting debris in the air. The radar was picking up on it and it was showing us a signal with one of the dual-polarization radar products that we couldn’t see before we got [the] upgrade.”
Meteorologists typically issue warnings when they spot a “hook echo,” the point where winds start rapidly swirling or rotating. Until now, they could never be certain that a tornado had actually touched the ground. They had to wait for reports from spotters and law enforcement to confirm it.
Now the presence of debris balls, even in the smallest tornadoes, allows them to issue a warning more confidently and word them more directly.
“Instead of looking for a second source of confirmation ... they will be able to say the National Weather Service is saying there is a tornado on the ground moving my way so I need to act now,” Nadler said.
He says the new technology will really come into play during nighttime tornadoes, which are harder to visually confirm because of darkness and the fact that fewer spotters are out watching for funnel clouds.
“Hopefully that information will help save lives down the road and that’s the key,” Nadler told Fox News.
Alabama has seen very active tornado seasons the past few years. In 2010 and 2011, the state ranked at the top of the list in confirmed tornadoes. So far, 50 radar sites in several states have been upgraded -- that includes every radar site in Alabama.
The remaining 110 sites will be upgraded throughout the year.