The Washington Post
By Jason Samenow and Greg Porter August 27 at 5:55 PM
(This story, published Sunday morning, will be updated throughout the day.)
The worst fears of flooding have been realized with Harvey as it unloads some of the most extreme rainfall Houston and other parts of Southeast Texas have ever witnessed. And much more rain is still to come.
“Catastrophic flooding in the Houston metropolitan area is expected to worsen,” the National Weather Service said Sunday. It added: “This event is unprecedented and all impacts are unknown and beyond anything experienced.”
One to two feet of rain have already fallen, with some locations nearing 30 inches.
“I know for a fact this is the worst flood Houston has ever experienced,” Patrick Blood, Weather Service meteorologist, told the Houston Chronicle.
The Weather Service said this August had become Houston’s wettest month in recorded history due to the storm. At the Weather Service office serving Houston in Dickinson, Tex. 24.1 inches of rain fell 24 hours.
The Weather Service said the “majority” of rivers and bayous around Houston were at record levels. Some were exceeding previous records by 10 feet.
Rainfall from Harvey in Harris County, the third most populous in the country and home to Houston, had exceeded the amount from Tropical Storm Allison, in half the amount of time (2 to 3 days, rather than 5), the Weather Service said Sunday afternoon. Allison was considered the previous flood event of record in the area.
The National Weather Service Weather Prediction Center is calling for an additional 15 to 25 inches of rain over the middle and upper Texas coast, including the Houston area, during the next several days. The National Hurricane Center said isolated storm rainfall totals could reach 50 inches, which would rival some of the most extreme rain events in U.S. history and break the state rainfall record in Texas.
A relentless band of heavy rain sat nearly stationary over Houston and its surrounding suburbs Saturday night. By Sunday morning, the effects of hour after hour of drenching rainfall started to take their toll, with widespread reports of high water on roadways. Bands of heavy rain continued to pivot through the Houston area Sunday afternoon but became somewhat more intermittent.
The NWS in Houston is not mincing its words about the danger of this unprecedented situation. The office issued multiple flash-flood emergencies, which extended into Sunday evening, shattering the precedent for issuance of such warnings locally.
At least five deaths have already been blamed on the storm, and over 1,000 water rescues have taken place in the Houston area as of Sunday afternoon. Local officials are pleading with the general public to not travel and to make sure they access their roof if the water rises too high in their homes rather than shelter in their attic.
“This disaster’s going to be a landmark event,” Brock Long, FEMA administrator, said on CNN’s “State of the Union” program. “This is a storm that the United States has not seen yet.”
So much rain has fallen that is has been extremely hard for first responders to keep up with the growing onslaught of rescue requests.
“We are facing a catastrophic multi-billion-dollar loss,” tweeted Steve Bowen, a meteorologist at reinsurer Aon Benfield.
The forecast doesn’t get any better for Houston. Harvey will continue to sit in a nearly stationary position on Sunday, keeping the Houston area under heavy rain bands of two to four inches per hour. And torrential rain could continue at times Monday into Tuesday.
Perhaps even more frightening, computer model forecasts are showing the very real possibility that Harvey will move back over the Gulf of Mexico Monday night and Tuesday, when it could restrengthen modestly. It may make a second landfall near Houston on Wednesday, with rain continuing into Thursday and even Friday.
In addition to the heavy rain, embedded thunderstorms have spawned more than a dozen tornadoes across the region, adding to the list of hazards brought on by Harvey. In fact, the Weather Service had issued more tornado warnings on (each of) Friday, Saturday, and Sunday than on any previous single day on record, for a total of 123 warnings.
This storm is unfortunately breaking all the wrong precedents. Things will only continue to get worse over the next 24 to 48 hours as more areas of the region receive overwhelming amounts of water with nowhere for it to go.