HOUSTON (AP) — High waters flooded neighborhoods around Houston on Saturday following heavy rains that have already resulted in crews rescuing more than 400 people from homes, rooftops and roads engulfed in murky water. Others prepared to evacuate their property.

A wide region was swamped from Houston to rural East Texas, where game wardens rode airboats through waist-high waters rescuing both people and pets who did not evacuate in time. One crew brought a family and three dogs aboard as rising waters surrounded their cars and home.

A flood watch was in effect through Sunday afternoon, as forecasters predicted additional rainfall Saturday night and the likelihood of major flooding.

"It's going to keep rising this way," said Miguel Flores Jr., of the northeast Houston neighborhood of Kingwood. "We don't know how much more. We're just preparing for the worst."

Husband and wife Aron Brown, 45, and Jamie Brown, 41, were two of the many residents who drove or walked to watch the rising waters near a flooded intersection close to the San Jacinto River. Nearby restaurants and a gas station were beginning to flood.

Water could be seen flowing into parts of the couple's subdivision, but Aron Brown said he wasn't worried because their home is at a higher elevation than others in the neighborhood.

Brown, who had driven from his home in a golf cart, said the flooding wasn't as bad as Hurricane Harvey in 2017. He pointed to nearby power lines and said that flooding during Harvey had reached the top of the lines.

RESIDENTS IN LOW-LYING AREAS ASKED TO EVACUATE

Friday's fierce storms forced numerous high-water rescues, including some from the rooftops of flooded homes. Officials redoubled urgent instructions for residents in low-lying areas to evacuate, warning the worst was still to come.

"A lull in heavy rain is expected through (Saturday) evening," according to the National Weather Service. "The next round of heavy rainfall is expected late (Saturday) into Sunday."

Up to 3 inches (7.6 centimeters) of additional rain was expected, with up to 5 inches (12.7 centimeters) possible in isolated areas.

Harris County Judge Lina Hidalgo said more rain was expected Sunday, and if it's a lot, it could be problematic. Hidalgo is the top elected official in the nation's third-largest county.

ONGOING RAIN HAS LEFT PARTS OF TEXAS DRENCHED, RESIDENTS TRAPPED

Most weekends, Miguel Flores Sr. is mowing his huge backyard on a 2.5-acre (1-hectare) lot behind his home in Kingwood. But on Saturday, he and his family were loading several vehicles with clothes, small appliances and other items.

Water from the San Jacinto River had already swallowed his backyard and was continuing to rise — what was about 1 foot (30 centimeters) high in the yard Friday measured about 4 feet (1.2 meters) the following day.

"It's sad, but what can I do," Flores said. He added that he has flood insurance.

For weeks, drenching rains in Texas and parts of Louisiana have filled reservoirs and saturated the ground. Floodwaters partially submerged cars and roads this week across parts of southeastern Texas, north of Houston, reaching the roofs of some homes.

More than 21 inches (53 centimeters) fell over a five-day period through Friday in Liberty County near the city of Splendora, about 30 miles (50 kilometers) northeast of Houston, according to the National Weather Service.

Hidalgo said Saturday that 178 people and 122 pets have been rescued so far in the county. Scores of rescues took place in neighboring Montgomery County. In Polk County, about 100 miles (160 kilometers) northeast of Houston, officials said they have done over 100 water rescues in the past few days.

HOUSTON IS ONE OF THE MOST FLOOD-PRONE METRO AREAS IN THE US

Authorities in Houston have not reported any deaths or injuries. The city of more than 2 million people is one of the most flood-prone metro areas in the country and has long experience dealing with devastating weather.

Hurricane Harvey in 2017 dumped historic rainfall that flooded thousands of homes and resulted in more than 60,000 rescues by government rescue personnel across Harris County.

Of particular concern was an area along the San Jacinto River, which was expected to continue rising as more rain falls and officials release water from a full reservoir. Hidalgo issued a mandatory evacuation order on Thursday for people living along portions of the river.

The weather service reported that the river was at nearly 74 feet (22.6 meters) late Saturday morning after reaching nearly 78 feet (23.7 meters). The rapidly changing forecast said the river was expected to fall to near flood stage of 58 feet (17.6 meters) by Thursday.

Most of Houston's city limits were not heavily impacted by the weather. Officials said the area received about four months' worth of rain in about a week's time.

The greater Houston area covers about 10,000 square miles (25,900 square kilometers) — a footprint slightly bigger than New Jersey. It is crisscrossed by about 1,700 miles (2,700 kilometers) of channels, creeks and bayous that drain into the Gulf of Mexico, about 50 miles (80 kilometers) southeast of downtown.

The system of bayous and reservoirs was built to drain heavy rains, but the engineering initially designed nearly 100 years ago has struggled to keep up with the city's growth and bigger storms.

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Associated Press reporters Ken Miller in Edmond, Oklahoma, Jim Vertuno in Austin, and Valerie Gonzalez in McAllen, Texas, contributed to this report.

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