• Texas Gov. Greg Abbott said dramatic flooding became his primary concern after Harvey was downgraded to a tropical storm Saturday.

• Mandatory evacuations were ordered for parts of the Houston metropolitan area near the Brazos River, which could experience a record crest.

• A specialist at the National Hurricane Center warned of life-threatening flooding after a multi-day rainfall disaster.

• Two storm-related deaths have been confirmed since Harvey made landfall on Friday.

VICTORIA, Texas After Hurricane Harvey was downgraded to a tropical storm on Saturday, meteorologists issued warnings about the potential for catastrophic and life-threatening flooding, as many areas between San Antonio and Houston are expected to get massive amounts of rainfall .

Meteorologist Ryan Maue said 20 trillion gallons of water could fall on Texas in the next week. Michael Lowry of the University Corporation for Atmospheric Research said that more than 60,000 square miles are under high or moderate risk for excessive rainfall through Sunday morning. At least two storm-related deaths have been confirmed, and imminent floods mean many more Texans could face danger in the next week.

During a press conference Saturday, Texas Gov. Greg Abbott (R) said dramatic flooding was his primary worry about the tropical storm, which barely moved throughout Saturday evening.

Our biggest concern is between 20 and 30 more inches of rain in areas ranging from Corpus Christi over to Houston, Abbott said. We want to do everything we possibly can to keep people out of rising water.

On Saturday, flooding caused the death of one motorist in Houston, according to Gary Norman, spokesman for the citys emergency operations center. He told the AP late Saturday that the person, identified as a woman, had been driving along flooded streets when she got out of her vehicle in high water . The cause of death has yet to be confirmed.

Earlier Saturday, C. J. Wax, the mayor of Rockport in Aransas County, confirmed the death of a man who died while trapped in his burning house, unable to be reached by rescuers during the height of the hurricane. Wax said at least 12 other people sustained injuries.

Rockport, where the storm made landfall Friday night, appears to be the hardest-hit area so far. The town of 10,000 is about 30 miles north of Corpus Christi, and has reported major damage to homes and businesses . Officials there told The Weather Channel that the loss of cellular coverage was hindering rescue work.