JOPLIN, Mo. - A new radar system helped meteorologists in Oklahoma detect debris from a tornado just as it was hitting Quapaw last month, but a similar radar in Missouri failed to see debris from the same storm when the EF2 twister bore moments later through Baxter Springs, Kansas.
Because of the earth's curvature, part of southeast Kansas is in a blind spot where the new dual-polarization radar at National Weather Service offices in Tulsa, Oklahoma, and Joplin, Missouri, can detect only the most destructive tornadoes, The Joplin Globe reported.
The Springfield office scans Cherokee County, Kansas, about 70 miles away.
Meteorologists there said the tornado that hit Baxter Springs on April 27, even with winds of 120 mph to 130 mph, wasn't strong enough to lift debris high enough into the lower atmosphere that it could be seen in Springfield.
Andy Boxell, a meteorologist in Springfield, says the weather service routinely uses Tulsa's radar for storms in Cherokee County because it is closer.
"We did not see the debris signature because we are so far away," Boxell said. "We can see for about 50 nautical miles. Baxter Springs is about 65 to 70 nautical miles away. If it had been a very strong tornado - a Joplin-like tornado, we would have been able to see it."
The tornado warning issued for Joplin on May 22, 2011 - a storm that killed 161 people and destroyed thousands of buildings - was based on observations of Tulsa radar when the storm was over Cherokee County.
The new radar, installed in Springfield and Tulsa two years ago, is the most significant enhancement to the nation's radar network since Doppler radar was first installed in the early 1990s.
Dual-polarization radar helps forecasters clearly identify rain, hail, snow or ice pellets, and other flying objects, including tornado debris that has been lofted into the air.
"It allows us to recognize what is rain, what is snow and what is sleet, but it also recognizes things that should not be up there, like sheet metal and roofing shingles that have been lodged upward by a tornado as debris," said Doug Cramer, a meteorologist in Springfield.
Keith Stammer, head of emergency management in Joplin/Jasper County, once served as emergency management director in Labette County, Kansas, which is west of Cherokee County.
He called that part of Kansas "sort of a radar no man's land."
The problem for Joplin and those points toward the east, he said, "is that a good portion of the tornadoes that affect Joplin spool up in northeast Oklahoma and southeast Kansas."