By Lisa Maria Garza and Jim Forsyth
DALLAS (Reuters) - Storms bringing as much as 7 inches (17.8 cm) of rain drenched North Texas overnight into Friday, prompting hundreds of calls for emergency assistance and adding to the woes of the state where at least 20 people have been killed in severe weather this week.
The National Weather Service issued a flash flood watch for an area from Central Texas into Kansas, with the additional rainfall swelling Texas rivers already at dangerously high levels.
The 7 inches in North Texas from Thursday morning into Friday comes after storms dumped as much as 11 inches (28 cm) overnight on Monday in the Houston area, where more than 4,000 structures were damaged in floods.
Hundreds of people spent the night in evacuation shelters across Texas as this week's floods turned streets into rivers, ripped homes off their foundations and swept over thousands of vehicles.
The Brazos River overflowed its banks about 30 miles (50 kms) west of Fort Worth, with hundreds of people leaving their homes in low-lying areas.
Police and fire crews were called out to help scores of people trapped in cars and houses by rushing water.
"Some of those rescues have come from cars driving into water and getting stuck, and others are homes which have become inundated with water," said Jamie Moore, the emergency management director for Johnson County, southwest of Fort Worth.
In Central Texas overnight, Travis County firefighters rescued 21 people from a drifting houseboat while Johnson County emergency workers rescued 14 drivers and residents. No injuries were reported, officials said.
Before Thursday night's storm, Texas climatologist John Nielsen-Gammon said so far in May the state had received 7.54 inches (19 cm) of rainfall on average. That breaks the record of 6.66 inches (17 cm) set in June 2004, based on records dating to 1895, according to Nielsen-Gammon of the Office of the Texas State Climatologist at Texas A&M University.
In flood-stricken Wimberley, near where at least seven people have been killed in floods, residents took time out from search and clean-up efforts for a graduation ceremony at their high school.
"Watching our kids for the past three days come and pick up shovels and go to neighborhoods and step in and help with clean up has just been awesome," said school district superintendent Dwain York.
(Writing by Jon Herskovitz in Austin, Texas; Reporting by Lisa Maria Garza in Dallas and Jim Forsyth in San Antonio; Editing by Susan Heavey and Bill Trott)
