Southeast Texas faced more heavy rainfall on Sunday, with forecasters warning that flash flooding could happen in Houston after several rounds of storms in the past few days prompted evacuations and rescues in the area.

The storms exacerbated dangerous conditions and forecasters said that once the storms passed, rivers could be swollen for days or even weeks.

About 2.1 million people in Texas were under flood warnings on Sunday morning, the Federal Emergency Management Agency said, with many flood gauges in Houston expected to reach or exceed their flood records.

The National Weather Service in Houston said that another one to three inches of rain was expected in Southeast Texas and that some places could see four to eight more inches of rain. Damaging winds, large hail and isolated tornadoes were also possible.

Heavy rainfall was expected to taper by Sunday evening, the Weather Service said. Forecasters said that because of the recent rounds of rainfall, flooding could occur earlier than would be expected in ordinary conditions.

The Harris County Office of Homeland Security and Emergency Management said that as of 10 a.m. on Sunday, there had been 233 rescues of people and 164 pet rescues in the county.

As of Sunday morning, the Texas authorities had not reported any injuries or deaths.

The potential for urban flash flooding in the Houston area was increasing on Sunday morning, the Weather Service’s Weather Prediction Center said, and the city was under a flood watch through the evening.

Flash flood warnings, which are issued by the National Weather Service when flooding is imminent, were in place on Sunday morning in several Texas counties, including Jasper, Newton and Tyler Counties.

Jeremy Justice, hydrological operations manager at Harris County Flood Control District, said on Saturday that some parts of Harris County could experience flooding near the record levels that were set during Hurricane Harvey in 2017, an event that claimed at least 68 lives and caused $125 billion in damage.

Several rivers in Texas had yet to reach their highest flows on Sunday, but were expected to crest in the next 24 hours, FEMA said. After cresting, the rivers’ recession would be slow, leaving the waterways above the major flooding stage through the middle of the week.

Eleven rivers were in a major flooding stage on Sunday, which means the flooding had caused an excessive inundation of roads and structures and required significant evacuations.

Another 18 rivers were experiencing moderate flooding, which can inundate some structures and may lead to evacuations.

The storms also caused power failures, with about 10,000 customers without power on Sunday afternoon, according to Oncor, a Texas energy company.