CORPUS CHRISTI, Texas (AP) — Authorities say rescue attempts continue in Houston for those stranded inside flooded homes and submerged vehicles in the wake of Harvey.

The Houston Chronicle reports that hundreds of calls have been fielded for water rescues as of early Sunday, including Houston police officials who evacuated two apartment complexes and rescued more than 50 children.

The National Hurricane Center says Harvey continues to cause “catastrophic flooding in southeastern Texas.”

The hurricane center says in its 4 a.m. Sunday update that the tropical storm has maximum sustained winds of 45 mph (72.42 kph) and remains stationary about 45 miles (72.42 kilometers) northwest of Victoria, Texas.

A storm surge warning and a tropical storm warning also are both in effect for Port O’Connor to Sargent. The hurricane center says a storm surge warning means there is a danger of life-threatening inundation from rising water moving inland from the coastline.

The center says Harvey is likely to weaken to a tropical depression later Sunday. Harvey made landfall Friday night as a Category 4 hurricane.

Meanwhile, the National Weather Service says a Flash Flood Emergency over west and central Harris County, where Houston is located, as well as for eastern Fort Bend and northern Brazoria counties remains in effect until 6:15 a.m. Sunday, calling it a “Particularly Dangerous Situation.”