Flooding from heavy monsoon season rains in the Phoenix area forced authorities on Tuesday to close several major roads, while elsewhere dramatic scenes were playing out as motorists were pulled from partially submerged vehicles and a helicopter crew rescued stranded residents from a home surrounded by swift-moving waters.
A small trailer park was evacuated in a town about 65 kilometres north of the metro area, and a north Phoenix high school temporarily relocated 12 classrooms of students because of flooding in portions of the building.
The National Weather Service issued a flash flood warning for much of the metro area and north of the city where up to 20 centimetres of rain fell by midday in some of the mountainous regions along the interstate.
The storms are expected to affect a large area of the state throughout the day.
"It's like a conveyor belt of showers coming through here," National Weather Service meteorologist Ken Waters said. "We're seeing new cells popping up in the Phoenix area and just outside the Phoenix area."
Sporadic storms are expected to continue in the area for the next few days.
Dramatic aerial television footage Tuesday showed a river of muddy water rushing down I-17 about 40 kilometres north of Phoenix as motorists changed lanes to avoid the deluge. Another scene showed authorities pulling an elderly woman from a van stuck in fast-moving floodwaters.
In New River, about 50 kilometres north of Phoenix, a helicopter lowered a rescuer to the roof of a home surrounded by rushing waters in an effort to pull trapped residents to safety. The scene played out on live television Tuesday afternoon as the rescuer tried to reach the residents.
Rocks also washed down a hillside onto I-17 about 95 kilometres north of Phoenix, causing several vehicle collisions, but no deaths or major injuries have been reported.