Apr 27, 2007 10:18 am US/Mountain
Radar 'Blind Spots' Exist In Southeast Colorado
National Weather Service Radar Has Hard Time Seeing At Low Elevations
by Paul Day
PUEBLO, Colo. (CBS4) ―
The same "low elevation" radar blind spots that made it difficult for National Weather Service meteorologists to warn the residents of Holly before a deadly tornado touched down last month exist over larger communities in southeast Colorado.
The thunderstorm that caused the category F3 tornado in Holly re-intensified so fast, according to forecasters at the NWS office in Pueblo, that the radar in Pueblo didn't give them an accurate picture of what was happening until it was too late.
As a result, the twister was first reported by people on the ground who called 911.
One person, Rosemary Rosales, died from her injuries caused by the tornado.
"It would have helped, some kind of warning would have helped," said Oscar Puga, Rosales brother-in-law.
The NWS said the problem is that the radar is 130 miles away from Holly. That means the curvature of the earth creates a "low elevation" blind spot over the town. The radar can't see activity below 11,500 feet.
"So there is a distance to the surface where it is impossible to see on the radar," said Bill Fortune, head of the NWS office in Pueblo.
In nearby Lamar, the blind spot is below 9,600 feet. In Springfield, Colo., the radar can't see below 12,300 feet.
"All of those communities in that area are going to be just below that radar beam," said Fortune. "It's going to be difficult for us to interpret exactly what's gong on on the ground."
The weather service is working on ways to reduce blind spots. A promising idea includes a network of low cost doppler radars that could be setup on rooftops or cell phone towers.
The idea could improve detection of low level tornadoes, but is still under development. At best, it is years away from deployment.
(© MMVII CBS Television Stations, Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed.)
