The worst fears of flooding are starting to be realized with Harvey as it unloads some of the most extreme rainfall Houston and other parts of Southeast Texas has 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 morning.
It later added: “This event is unprecedented and all impacts are unknown and beyond anything experienced.”
One to two feet of rain has already fallen, with some locations nearing 30 inches.
“I know for a fact this is the worst flood Houston has ever experienced,” Patrick Blood, National Weather Service meteorologist, told the Houston Chronicle.
The Weather Service office in Houston reported 24.1 inches of rain in 24 hours as of 7 a.m. Sunday morning and said this August had become the wettest month in recorded history due to the storm.
It added the “majority” of rivers and bayous around Houston were at record levels. Some were exceeding previous records by 10 feet.
“Volume-wise, this has liked reached the rainfall that fell during Allison in June 2001, and it continues to rain,” said the Weather Service office in College Park, Maryland, responsible for rainfall forecasts.
The National Weather Service Weather Prediction Center is calling for an additional 15-25 inches of rain over the middle and upper Texas coas, 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.
At least five deaths have already been blamed on the storm, and more than 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.
The NWS in Houston is not mincing its words about the danger of this unprecedented situation. The office issued multiple flash flood emergencies, shattering the precedent for issuance of such warnings locally.
Perhaps even more frightening, computer model forecasts are showing the very real possibility that Harvey will move back over the Gulf of Mexico early next week and make a second landfall near Houston on Wednesday.
In addition to the heavy rain, the strong line of thunderstorms spawned more than a dozen tornadoes across the region, adding to the list of hazards brought on by Harvey. In fact, the National Weather Service in Houston said Sunday it issued more tornado warnings on both Friday and Saturday than on any single day on record.
This storm is unfortunately breaking all the wrong precedents. Things will only continue to get worse over the next 24-48 hours as more areas of the region receive overwhelming amounts of water with nowhere for it to go.