【1991 Archives】

Weather forecasters' worst fears regarding Hurricane Harvey991 Archivesbeing realized in Houston, the nation's 4th-largest city, as a historic deluge pounded the city overnight and into Sunday morning, with no signs of relenting.

Widespread, "catastrophic" flooding is occurring, with emergency responders struggling to rescue people from rapidly flooding homes.

SEE ALSO: Hurricane Harvey: A weather geek's live blog

Officials report at least 1,000 people were rescued overnight from rising waters, and the National Weather Service (NWS) has been issuing some of the most dire flood warnings in its history, including calling the storm "unprecedented."

This Tweet is currently unavailable. It might be loading or has been removed.

After 1 to 2 feet of rain fell on Saturday into Sunday morning, much of it in a deluge overnight, a flash flood emergency -- the highest category of flood warning -- was issued for all or parts of 11 counties. With 1 to 2 feet of additional rainfall expected, the flooding is sure to worsen, according to the National Weather Service (NWS).

“Catastrophic flooding in the Houston metropolitan area is expected to worsen and may become historic,” the agency said in a technical forecast discussion on Sunday morning.

The NWS is calling for as much as 50 inches of rain from Harvey across the Houston and Galveston areas once this event ends in the next few days. If this nearly unfathomable rainfall total is realized, it would qualify as the most rainfall from any tropical cyclone (hurricane or tropical storm) in U.S. history, according to meteorologist Michael Lowry.

The previous record was 48 inches, set in Tropical Storm Amelia in 1978, which also struck Texas.

Mashable Light Speed Want more out-of-this world tech, space and science stories? Sign up for Mashable's weekly Light Speed newsletter. By clicking Sign Me Up, you confirm you are 16+ and agree to our Terms of Use and Privacy Policy. Thanks for signing up!

This Tweet is currently unavailable. It might be loading or has been removed.

This Tweet is currently unavailable. It might be loading or has been removed.

This Tweet is currently unavailable. It might be loading or has been removed.

This Tweet is currently unavailable. It might be loading or has been removed.

The deluge has already been enough to push Houston over the top to set a record for the wettest August on record.

This Tweet is currently unavailable. It might be loading or has been removed.

And the rain is not over yet -- not by a longshot. Heavy rain is forecast to continue in the Houston area for much of Sunday, with periods of heavy rain all the way through Thursday. In fact, some meteorologists are suggesting this flood event could go down in history books as one of the -- if not the worst flood in U.S. history, based on the forecast for 2 feet or more of additional rainfall.

This Tweet is currently unavailable. It might be loading or has been removed.

The rainfall amounts as well as the geographic scope of the flooding has exceeded a benchmark flood for the area, which was also related to a slow-moving tropical storm. Tropical Storm Allison killed 41 and did $9 billion in damage when it hit in 2001. This storm will likely cause far more damage, in part because the region is even more urbanized now, as well as because of the broader footprint of heavy rain totals from this storm.

Some of the heaviest rain has fallen on the southeast side of the city, where Houston's Hobby International Airport had to close due to the flooding.

Houston is particularly prone to flooding from heavy rainfall. A network of bayous crisscrosses the city, and they are both a blessing and a curse, since they help to drain rainwater from the city but can be a cause of major flooding when they overflow. As of Sunday morning, most bayous, flood channels, and rivers in the Houston area were well above their banks, and many have already hit record levels and rising.

Original image has been replaced. Credit: Mashable

Images on social media have shown the severity of the flooding.

This Tweet is currently unavailable. It might be loading or has been removed.

This Tweet is currently unavailable. It might be loading or has been removed.

This Tweet is currently unavailable. It might be loading or has been removed.

This Tweet is currently unavailable. It might be loading or has been removed.

Forecasts call for waves of heavy rain to continue to affect Houston during the next 12 to 18 hours, and possibly as long as the next 2 days, as Harvey keeps a firehose of moisture from the Gulf of Mexico pointed at the Texas coast.

This Tweet is currently unavailable. It might be loading or has been removed.

This Tweet is currently unavailable. It might be loading or has been removed.

This Tweet is currently unavailable. It might be loading or has been removed.

"It’s bad and it’s going to likely stay bad through the day," said the Houston weather blog Space City Weather.

The rains are directly tied to the nearly stationary Tropical Storm Harvey, which is pinwheeling across southeastern Texas, cut off from atmospheric steering currents that could push it out of the area. Some computer models even take Harvey back out into the Gulf of Mexico, where it could re-intensify somewhat, and then back over land in northeast Texas.

Across much of the U.S. and around the world, extreme rainfall events are becoming more common as the world warms. In addition, scientists expect that as human-caused global warming continues and the atmosphere holds more moisture, tropical storms and hurricanes will produce heavier rains.  

This Tweet is currently unavailable. It might be loading or has been removed.

---

Featured Video For You

---

Hurricane Harvey is intensifying in the Gulf of Mexico

---