Finger on the Weather

‘Insane’ rains echoed storms that spawned deadly Kansas Turnpike flood, official says

The heavy rains that triggered deadly flooding in southeast Kansas Tuesday are being compared to downpours that spawned a killer flash flood on the Kansas Turnpike 15 years ago.

Dennis Clark Catron Sr., 72, and his son, Dennis Clark Catron Jr., 39, were swept off a Montgomery County road at a low-water crossing north of Elk City Lake on County Road 2950, authorities say. Law enforcement officials were notified of the incident shortly after midnight Tuesday after hours of heavy rain.

The National Weather Service in Wichita reported that nearly 9 inches of rain fell at reporting stations in the area, but radar estimated up to 11 inches fell in rural areas with no rain gauges.

“It’s just insane rainfall” amounts, said Andy Kleinsasser, a meteorologist with the weather service.

One storm after another tracked over the same area, which meteorologists call “training” because the thunderstorms seem to be on railroad tracks.

Rainfall rates approached three inches an hour at times and continued for several hours.

A “very tropical air mass” was responsible for the storms, Kleinsasser said.

Most Great Plains thunderstorms surge into the upper atmosphere, producing lots of hail stones as the rain is hoisted so high it freezes. As the hail melts lower in the clouds, Kleinsasser said, it produces big rain drops that then fall to the ground.

Those storms, while more violent, don’t always produce a lot of rain, he said.

Tropical systems like Tuesday’s are more commonly seen on the Gulf Coast.

“They’re very, very efficient” rain producers, Kleinsasser said, because the drops are small and packed closer together.

“Rainfall like that can add up quicker than the big-drop rainfall,” he said.

The southeast Kansas storms on Tuesday were similar to the heavy rains that pummeled the Flint Hills over Labor Day weekend in 2003, Kleinsasser said, spawning a flash flood that killed six people on the Kansas Turnpike.

An estimated 6 to 8 inches of rain fell over a four-hour period near Jacob Creek spanning late Aug. 30 and early Aug. 31, according to an analysis of the event by a team of weather officials. The runoff overwhelmed a drainage culvert and covered the turnpike.

Eventually, pressure from the rising water swept a dozen concrete barriers in the median and more than a half-dozen vehicles into Jacob Creek.

The six people who died included five members of the Rogers family returning to Kansas City from a family wedding in Wichita.

Such slow-moving, tropical air masses that produce heavy rains are not foreign to Kansas, Kleinsasser said.

“They tend to strike in August and September,” just like the 2003 storm, he said.