Three days after landfall and after traveling over more than 850 miles of land, Bill is still a tropical depression as it swirls over Missouri. The storm has produced catastrophic flooding along its path, and more flooding is likely through the Ohio Valley and eventually into the I-95 corridor of the Mid-Atlantic.
Bill pushed its way inland after making landfall on Matagorda Island in Texas on Tuesday morning, swirling through Dallas-Forth Worth on Wednesday before crawling through eastern Oklahoma and eventually into Arkansas. The center of Tropical Depression Bill is very close to Cape Girardeau, Missouri, at this hour, moving east toward Kentucky.
The system should finally degenerate into a post-tropical cyclone within the next day as it continues moving east, approaching the Washington D.C. and Philadelphia areas as a trough with the threat for heavy rain late Saturday and early Sunday.
It’s not too unusual to see a tropical depression over Missouri, especially if the storm is moving at a fast clip after it makes landfall along the Gulf Coast. However, it’s not every day that you see a cyclone still clinging to tropical depression status three days after landfall as it crawls into the middle of the United States. The fact that it’s still alive after spending so much time over land is a testament to the muggy, tropical airmass present over the region.
Even though skies are clearing out, Bill’s effects are still hanging around. Sadly, the predictions of disastrous heavy rainfall came true. After dumping up to ten inches of rain around Victoria, Texas, the rain let up a bit until it made it to Dallas.
Though the Metroplex generally saw one to three inches of rain, much heavier rain fell just upstream, resulting in considerable flooding in the region. The heavy rain in northern Texas pushed the Trinity River far above its banks in downtown Dallas, engorging the normally-tiny body of water many times its normal size. Under normal circumstances, this section of the river is no wider than a four-lane highway.
The worst flooding occurred near hilly terrain in southern Oklahoma around the city of Ardmore. Bill slowed down considerably as it moved through northern Texas and southern Oklahoma, creating an ideal setup for extremely heavy rain across the area. As if its snail-like forward motion wasn’t bad enough, the terrain helped wring out every little bit of tropical moisture from Bill as it swirled over the area on Wednesday and Thursday; the National Weather Service estimates that some areas in southern Oklahoma have received up to 20 inches of rain over the past seven days, most of which fell during Bill.
Locations in and around Ardmore were placed under a flash flood emergency during the event, with waters rising so quickly that many residents didn’t have time to act before they were surrounded by the flood. The flooding claimed several lives, including an Ardmore toddler who was carried away by the rising water as his family tried to evacuate their home, and a woman who drowned in her car after she attempted to drive through a flooded roadway in Tecumseh.
The heavy rains are putting stress on already-strained water infrastructure in the region, threatening dams and bridges around the region. A river gauge at the I-35 bridge over the Red River in Gainesville, Texas, is at record flood stage right now, sitting at a record-high crest of 42.05 feet right now. The previous record crest was 40.08 feet set back on May 31, 1987.
The water is so high that it’s expected to reach the low chord, or underside, of the I-35 bridge before receding. Flooding on this section of the Red River begins at 25 feet, and the normal depth of the river is between 10 and 15 feet.
The Weather Prediction Center expects a general swath of two to three inches of rain as Bill (and its remnants, if it ever dies) makes its way into the Ohio Valley and eventually the Mid-Atlantic before scooting out into the Atlantic Ocean. Some areas could see more rain than this if they get caught under heavier thunderstorms, and it won’t take much rain over a short period of time to trigger flash flooding on the region’s saturated soil. The greatest threat for flooding exists over areas that have already seen heavy rainfall, including Washington D.C. proper, which saw extremely heavy rain from thunderstorms on Thursday night.
The good news, though, is that it looks like the south-central United States will have a chance to dry out over the next week or so, and the National Hurricane Center doesn’t expect any new tropical cyclones to develop in the Atlantic or the eastern Pacific over the next five days. The bad news is that the lingering heat wave across the southeast is going to get even worse next week.
[Images: NASA, author, NWS, author]