Over 130 people have died after heavy rain pounded Kerr County, Texas, early Friday, leading to "catastrophic" flooding, the sheriff said.

Experts said warnings issued in the run-up to this weekend’s flooding were as timely and accurate as possible, but questions about whether the alerts reached people most at risk remain.

On Sunday at 2:33 p.m. the National Weather Service issued a flood advisory in effect until 4:30 p.m. for Houston County.

When the National Weather Service Office issues a flood watch, or a flash flood watch, the forecast has the potential for rainfall of one inch per hour or repeatedly over a span of a few or many hours. These locations indicated by the watch should be aware of their locations and surroundings regarding the flooding potential.

"It's not community to community. It's a national system," Sen. Maria Cantwell said on "Face the Nation with Margaret Brennan."

The weather service predicts that parts of Maryland remain at risk for excessive rainfall and the potential for flash floods.