NEWS

Arkansas, southern Missouri in bullseye for 6-day deluge

Wes Johnson
WJOHNSON@NEWS-LEADER.COM
The National Weather Service in Springfield released this rainfall projection map late Monday.

A soggy, persistent storm system could dump 3 to 6 inches of rain or more on Springfield and areas south of I-44 before the spigot is turned off on Sunday.

The National Weather Service has rain or thunderstorms in the forecast every day through Saturday, with north central Arkansas forecast to get up to 5 inches by Saturday.  Areas south of Little Rock could get from 7 to 9 inches of rain, according to weather service forecasts.

There is the potential for  moderate to serious flooding on creeks and rivers south of I-44 if this excessive rainfall materializes, according to the weather service.

A few strong thunderstorms could develop Tuesday across southwestern Missouri and southeastern Kansas. Gusty winds and marginally severe hail will be the primary concerns.

The deluge comes a few months after a similar event in late December that dumped more than 10 inches of rain on the Ozarks and caused significant flood damage. U.S. Army Corps lakes rose very quickly, and the Corps spent weeks releasing pent-up floodwater from Beaver, Table Rock, Bull Shoals, Norfork, Greers Ferry and Clearwater lakes.

Those have been returned to seasonal conservation-pool levels to be readied for the typical spring rainy season.

“We’ve gotten all of the White River reservoirs back to the top of conservation pools and are ready for the projected heavy rain next week,” said Mike Biggs, chief of the Hydraulics and Technical Services Branch.  "We were able to evacuate all of the flood storage from December because rainfall in January and February was well below average.

"We had two warm, dry months.  As always, we’ve been following our water control plan and have lowered the reservoirs knowing that spring is the typical rainy season. We’re not sure yet exactly where the forecasted rain will fall, but the forecast shows heavy rain will fall above and below the dams."

Even though the reservoirs are ready to catch runoff, they are not intended to and cannot prevent all flooding, the Corps says.  Rather, the dams were designed to reduce the peak of the flood.  Those living around the reservoirs or downstream next to the rivers and creeks live with the risk of flooding every time it rains heavily.

“Right now, the National Weather Service forecast has the bulk of the rain falling below our White River lakes in the uncontrolled runoff area and we do not have the ability to hold that water back, said Biggs.  “But the area forecasted to receive the most rainfall has shifted several times so far,” added Biggs.  “That is why we never prerelease water from our reservoirs based on a forecast.”

Also, rainfall forecasts are not sufficiently accurate to base operational decisions.  Engineers have to know the amount of rain, its intensity, and its duration to calculate runoff over very large areas.  Just because the broadcasted weather forecast shows rain, it does not provide this level of detail.

“We’ve been releasing water from our White River reservoirs since the end of December 2015, we’ve just now gotten back to the top of our conversation pools,” said Biggs.  “Even if we could prerelease to lower a reservoir in anticipation of a forecasted rain event the forecast is not accurate enough to precisely time and size our releases.  If we did prerelease we could be creating more damage downstream than the actual flooding event itself.”