Flooding forced residents to flee hundreds of homes in northwestern Iowa early Saturday after weeks of drenching rain left nowhere for the water to go.

Emergency sirens sounded at 2 a.m. in the city of Rock Valley, about 45 miles north of Sioux City, when the nearby Rock River couldn't handle any more runoff from the ongoing deluge, the Associated Press reported.

Drone video posted on social media by the Sioux County Sheriff's Office showed low-lying streets and yards covered by murky floodwater, with trees and roofs sticking out of the overflow.

"We've had so much rain here," Rock Valley Mayor Kevin Van Otterloo said. "We had four inches last night in an hour and a half. Our ground just cannot take anymore."

The city, population 4,200, no longer had any running water because local wells were unusable, AP said.

Gov. Kim Reynolds declared a disaster for Sioux County, which covers Rock Valley.

In the nearby city of Spencer, Aiden Engelkes, 20, said he and his girlfriend had to grab their cats, along with clothing and bottled water, when their first-floor apartment flooded.

They were able to relocate upstairs to a friend's fourth-floor apartment, Engelkes said, unlike some friends who were stranded on a roof across the street, waiting for help.

"It's terrifying," he said.

Flooding also forced the closing of several highways in northwestern Iowa and southeastern South Dakota, including a stretch of Interstate 29, south of Sioux Falls, South Dakota, where no alternate routes were available, AP said.

Sioux Falls, the state's largest city, got more than 7 inches of rain in three days.

In New Mexico, heavy rain and flash flood warnings prompted mandatory evacuation orders, including around the state's largest city of Albuquerque, which lies along the Rio Grande.