Updated

Thunderstorms raced through the Houston area Thursday, aggravating flooding in already drenched parts of the city as mandatory evacuations were ordered for low-lying neighborhoods in a community about 50 miles away.

Houston and surrounding counties have received more than a foot of rain since Sunday night, and the flooding has forced thousands of people from their homes as creeks and bayous became overwhelmed. At least eight deaths have been blamed on the weather.

A heavy rainstorm Thursday morning dumped more than an inch of rain in less than an hour in some areas of Harris County, which includes most of Houston.

"We're seeing some minor rises in some creeks," Jeff Lindner, with the Harris County Flood Control District, said. "It doesn't look like we'll see enough rain to see more widespread flooding."

Water likely would collect in some streets but subside once the rain stopped, he said.

Two aging reservoirs in west Houston considered "extremely high risk" by the U.S. Army Corps of Engineers were holding record amounts of water -- at 50 percent capacity -- but remained in good shape, he said.

Meanwhile, officials in Wharton, a community of about 8,700 residents about 50 miles southwest of Houston, ordered residents to leave their homes in some low-lying neighborhoods along the rain-swollen Colorado River. The river's flood stage is 39 feet but the river level there exceeded 47 feet Thursday and some streets were underwater.

Flood warnings remained in effect for several southeastern Texas counties. Forecasts expected conditions to improve starting Friday.