PHOENIX (AP) — Flooding from heavy monsoon season rains in the Phoenix area forced authorities on Tuesday to close several major roads, including a portion of Interstate 17, 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 40 miles 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 8 inches 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 25 miles 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 30 miles 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.
The Arizona Department of Public Safety closed a roughly 15-mile stretch of I-17, redirecting traffic into the southbound lanes back toward Phoenix.
Officials said it’s unclear when the highway will reopen, and Waters expects several more inches of rain in the area over the next few hours.
The Arizona Department of Transportation will have to clear the road of mud and debris when the floodwaters recede to allow authorities to reopen one lane at a time hopefully by the afternoon, DPS spokesman Bart Graves said.
‘‘Earlier we were very concerned that it was moving so fast that it would take over I-17 completely both northbound and southbound,’’ Graves said. ‘‘But it didn't, so now ADOT is going to have to sweep that water out of there, which is going to be a long, arduous project.’’
Rocks also washed down a hillside onto I-17 about 60 miles north of Phoenix, causing several vehicle collisions, but no deaths or major injuries have been reported, Graves said.
Meanwhile, residents of a small trailer park in Black Canyon City along a river about 40 miles north of Phoenix were evacuated late Tuesday morning, according to the Yavapai County Sheriff’s Office.
There had so far been minimal flooding damage to the park, but authorities wanted to get residents to a safe location because water has damaged roads in the vicinity, sheriff’s spokesman Dwight D'Evelyn said.
Firefighters from Phoenix and the Daisy Mountain Fire District on Phoenix’s northern outskirts rescued at least six motorists in separate incidents, Phoenix Fire Capt. Benjamin Santillan said.
‘‘We've got units jumping from one car to the next to the next,’’ Santillan said, adding that there have been no reports of injuries.
Floodwaters also filled Skunk Creek in the New River area north of Phoenix, carrying debris that included plastic plant pots from a nursery, tires, coolers and garbage bins.
Several other roads north of Phoenix also have been closed due to flooding.