The storm system that swept through southern and central USA from 20 May, 2019 has caused rivers to rise dramatically, prompting evacuations in Oklahoma and Arkansas. Major flooding had already affected parts of Oklahoma and Missouri by 22 May.
National Weather Service (NWS) Arkansas-Red Basin River Forecast Center reported on 27 May that rivers in the area were above flood stage in 81 locations (including Major Flood Stage in 23 locations) from Wichita, Kansas to Little Rock, Arkansas. By 31 May this figure is expected to increase to 96 locations.
Arkansas
Arkansas Governor Asa Hutchinson declared a state of emergency on 24 May in anticipation of severe flooding. A statement declaring the emergency said, “The Arkansas River is expected to crest at record levels this weekend and continue through next week. The Governor encourages Arkansans to stay alert and heed the warnings of local emergency management officials.”
The governor ordered 2 National Guard high-water teams to western Arkansas. The State Emergency Operations Center is active at Level I (Full Activation).
NWS Little Rock forecasts that over the coming days the Arkansas River will exceeded previous record highs in 5 locations. The river at Van Buren near Fort Smith was already at record levels on 26 May, standing at 38.7 feet (11.79 metres), where flood stage is 22 feet (6.7 metres). As many as 200 residents in the area evacuated their homes on 25 May.
Oklahoma
In Oklahoma, Governor Kevin Stitt amended an earlier State of Emergency to include all 77 counties due to flooding, severe storms, tornadoes, and straight-line winds that began in the state in April this year. On 26 May, President Trump signed an Emergency Declaration for Oklahoma making available federal emergency aid for Haskell, Kay, Le Flore, Muskogee, Noble, Osage, Pawnee, Sequoyah, Tulsa, and Wagoner counties.
As of 25 May, 2 fatalities had been attributed to flooding and severe weather in the state according to Oklahoma Department of Emergency Management: one in Payne County and another in Stephens County. As many as 83 people have been injured.
Evacuations have been carried out in Muskogee, Ponca and Wagoner counties, as well as in the Tulsa area. Officials estimated that about 1,000 homes have been damaged by flooding over the last few days. Roads have been closed in at least 17 locations.
Among the worst hit areas is the town of Braggs in Muskogee County, which has been completely surrounded by flood water from the overflowing Arkansas river. As of 27 May the Arkansas river near Muskogee stood at 46.39 feet (14.14 metres). Major flood stage is 34 feet (10.36m) and record high is 48.2 feet (14.69m).
Areas around Tulsa have also been badly hit, with residents living near the Arkansas River urged to leave their homes. Mayor of Tulsa, G.T. Bynum said “We encourage people living behind Levees A and B to proactively relocate.” Evacuation centres have been set up in the city. As of 27 May, the Arkansas river at Tulsa was at 22.24 feet (6.78 metres), where flood stage is 18 feet (5.48m) and record high is 25.2 feet (7.68m).
After further rain flowing into the Keystone basin from a storm on 25 May, the Army Corps of Engineers announced they will increase the Keystone Dam release from 250,000 Cubic Feet Per Second (CFS) to 275,000 CFS. A map (shown below) of areas near Tulsa at risk from the Keystone Dam release can be found here.
