The flood watch remains in effect for about a dozen counties in southeast Texas, where heavy rain has turned streets into rivers.
A forecaster says the bad weather should end in the Houston area by tomorrow.
More than ten inches of rain has fallen in Harris County, leaving waist-deep water in a neighborhood near Hobby Airport.
The airport itself also was affected, with about 50 arrivals and departures canceled yesterday.
Houston's mayor says there were hundreds of 911 calls from motorists stranded on flooded roads.
In Sulphur, Louisiana, more than 100 patients were evacuated from a nursing home that flooded after debris plugged up a storm drain near the back door.