Heavy rain is expected to bring a risk of flooding to already saturated areas of the southwestern United States.

Heavy rain beginning Saturday evening is expected to bring a threat of flash flooding to already saturated areas of the southwest United States through Monday, according to the National Weather Service.

Up to 10 centimeters of rain could fall on the region, where a number of weather systems have brought a deadly fall of torrential rain. Emergency crews in the Phoenix area rescued people from several vehicles on flooded streets Friday evening.

“It won’t take a lot of precipitation to have an impact in some of these places, just because of how saturated they are,” said Allison Santorelli, a meteorologist at the Weather Prediction Center in College Park, Maryland.

The National Weather Service has issued flood warnings for almost all of Arizona and parts of southern Utah, southwest Colorado and western New Mexico, in addition to part of southern Nevada. These watches include the Four Corners region, a sparsely populated area where Arizona, Colorado, New Mexico and Utah meet and which has been particularly hard hit by recent rains.

Santorelli said this weekend’s rains are expected to cause both flash flooding and flooding of small streams.

The Phoenix Fire Department said in a post on

Scottsdale Fire Capt. Dave Folio said in a video posted to Facebook that just 2 inches (5 centimeters) of water can “sweep your vehicle off its wheels” and that vehicles were in 3 to 4 feet (0.9 to 1.2 meters) of water.

In Bullhead City, Arizona, located on the state’s border with California, heavy rains Friday left water, rocks and debris on city streets and closed parks, the city said in Facebook posts.