Houston braces for more heavy rain as overflowing rivers force evacuations

May 4 (UPI) -- The Houston area is facing more heavy rain over the weekend as the region struggles to cope with widespread and "historic" flooding that has triggered evacuation orders.

The National Weather Service in Houston said that while Saturday would see some isolated thunderstorms, the region would face a new, significant threat later in the day and into Sunday when it will be socked with "another round of heavy rainfall" following multiple rounds of heavy rain, high winds and lightning this week.

The heavy rain led to severe flooding in the Houston area later Saturday. Harris County officials said at least 178 people were rescued from vehicles and homes. No deaths or serious injuries were reported.

Flood watches remain in effect for the area city until Sunday afternoon as 1 to 3 inches or more of additional rain is possible Saturday night into Sunday. Moderate to "major" flooding is predicted to continue along the San Jacinto and Trinity rivers into next week.

"The grounds are super saturated, so any additional rainfall will likely result in flooding," forecaster warned .

State transportation officials remained fanned out across Houston on Saturday to battle widespread road flooding, including along the major Interstate 69/U.S. Hwy. 59 corridor, where the East Fork of the San Jacinto River had overspread the roadway.

Officials urged residents to avoid driving through standing water, warning it can be impossible to tell how deep the water is or how fast it is moving.

The brunt of the flooding is being felt in Montgomery County north of Houston. There, the West Fork of the San Jacinto has covered many of streets in the town of Woodloch, Texas, necessitating rescues.

The sheriff's department said its high water rescue teams are assisting with water rescues as additional emergency shelters were opened.

Montgomery County emergency officials said they and members of the Conroe, Texas, Fire Department used watercraft to rescue more than 30 people near the San Jacinto River on Friday after receiving calls for help.

"The current from the San Jacinto River is extremely strong in this flooded area, and the firefighters are performing these rescues at great risk," EMS officials said in a Facebook post . "If you are still in a flooded area, call 9-1-1 and get out now, don't wait."