Houston and much of southeast Texas was paralyzed Thursday by catastrophic flooding caused by Tropical Depression Imelda.

The National Weather Service calls it “an incredibly dangerous, life-threatening situation.”

“Roughly two feet of rain has engulfed the vast, highly populated area since Wednesday morning, while some areas have seen over three feet,” the Washington Post reports. 

And it’s far from over.

“We’re still putting water on top of water,” said Jeff Linder, meteorologist of the Harris County Flood Control District.

Gov. Greg Abbott declared a state of emergency in 13 counties. More than 75,000 homes and businesses were without power. A possible tornado was reported in southwestern Louisiana.

Houston Mayor Sylvester Turner and law enforcement officials are pleading with everyone in the region to remain where they are and stay off flooded roads.

In a Twitter post, meteorologist Eric Holthaus declared it “one of the worst fresh-water floods in American history,”  calling Imelda “a 1-in-1000 year rainfall event, just two years after [Hurricane] Harvey (also a 1-in-1000 year event).”

Imelda is now among the top five wettest tropical storm systems ever to strike the contiguous 48 states.

Emergency 9-1-1 call centers were overwhelmed with pleas for help. More than 1,000 people were rescued or evacuated from floodwaters in Harris County alone, according to the county fire marshal. 

Houston’s George Bush Intercontinental Airport was closed, with hundreds of flights cancelled, weather.com says, citing the air-transport website flightaware.com. The airport reported getting nearly 6 ½ inches of rain in two hours on Thursday morning; it averages just over 4 inches for the whole month of September.

Rail and bus services were also shut down throughout the region.