It just keeps getting worse. The gully-washers and toad-stranglers are in full force across Texas and Oklahoma at this hour as the region stares down the barrel of more heavy rain and flooding after years of thirsting for some delicious sky water. Some spots could see double-digit rainfall totals by this time next week.
A favorable jet stream and winds from the south mean that the floodgates are open for deep, tropical moisture to pour into the central United States from the Gulf of Mexico, and this ribbon of evaporated paradise is allowing thunderstorms to unload wherever they happen to set up. The shape of the jet stream is favorable for troughs and surface lows to keep spinning up over the central Plains, allowing heavy rain and thunderstorms to plague the entire south-central United States, but especially Texas and Oklahoma.
These rainfall totals aren’t exactly a sneeze’s worth, either—Oklahoma City has seen nearly five times its normal rainfall for the month of May, recording 12.83 inches for the month compared to the month-to-date normal of 2.73 through May 18. Totals aren’t quite as prolific farther to the south, but Dallas is sitting at 6.30 inches for the month, which is double DFW Airport’s month-to-date normal of about three inches.
It’s a far cry from where the area was this time last year.
As shown by one of The Vane’s classic Terrible Excel Charts above, the gauge at Will Rogers World Airport southwest of Oklahoma City has seen 22.03 inches of rain for the year, which is more than ten inches wetter than the city should be by this point in the year. Compare that to where the rainfall situation stood on May 18, 2014, when the city had only seen a five-and-a-half month tally of 3.94 inches. Other cities across the state haven’t seen as much as the capital, but virtually all of Oklahoma (save for the northeast borderlands near Kansas/Missouri) is now above-average for the year.
A similar story is playing out across the Red River, where most major cities in Texas are sitting pretty with above-average rainfall for the year, most of which has fallen in the past couple of weeks. The big five—Houston, San Antonio, Dallas, Austin, and Fort Worth—are all approaching twenty inches of rain for the year, with DFW and Houston Intercontinental surpassing the mark. Again, this year’s totals dwarf the paltry amounts that fell through the middle of May last year.
A steady stream of voluptuous thunderstorms over the next week or so will help pad these totals even further, not only rapidly bringing the region out of what’s left of its drought, but carrying with them the threat for flash flooding. It won’t take much rain in a short period of time across the south-central United States (not just Texas and Oklahoma) to lead to flash flooding, and each heavy thunderstorm makes it harder for the ground to absorb additional water, requiring even less rain for flash flooding. It’s a nasty feedback cycle that can pose lethal hazards to anyone caught in the wrong place at the wrong time.
The Weather Prediction Center expects a large swath of five or more inches of rain over the next seven days, with parts the Red River Valley at risk for seeing seven or more inches fall through next Tuesday. Rainfall from thunderstorms is highly localized, and it just takes one storm stalling out or a training line to produce copious totals in a short period of time.
Do not drive through a flooded roadway. Always assume you won’t make it. If you want to risk a violent death, that’s on you, but don’t risk the lives of the people who have to come out there to save you or recover your body, and especially don’t do something stupid like that if you have passengers.
Even though this advice is repeated time after time, people don’t listen because they think they know better. More than half of all flood-related deaths occur in vehicles, and the water can take away a heavy-duty pickup track almost as easily as it can claim one of those little Smart Fortwo things.
Just yesterday in Ruston, Louisiana, a woman driving with her two children attempted to navigate through a flash flood, and their car was swept away by the swiftly-moving waters. She managed to save herself, the 7-year-old clung to a tree and was rescued, and the 11-year-old drowned in the vehicle.
The best advice is to just stay home during a flash flood warning, but that’s not always feasible; most people will have to venture out at some point. If you’re out, take it slow and keep an eye out for ponding on the roadway. It’s often hard or impossible to judge water depth on a road. If you’re unsure, heed the National Weather Service’s flood safety motto: “turn around, don’t drown.”
[All maps/terrible charts by the author]