A flash flood warning was issued for Flagstaff and surrounding areas in Arizona after heavy rains caused massive flooding on Sunday.

The rain that started around noon flooded streets and homes in the Sunnyside and Southside neighborhoods and also caused a river to flow down Butler Avenue, forcing closure of the area.

The floods also caused multiple vehicles to be stuck in water in areas such as Cottage Street. Several traffic lights stopped working, power was knocked off and underpasses became treacherous in the city.

Arizona Department of Transportation officials cautioned drivers to slow down on Interstate 7 south of Flagstaff and State Route 89A also faced delays due to the rainfall, local daily 12 News reported.

An estimated 1.5 to 2.5 inches fell in an hour, The National Weather Service said.

It has also recommended moving to higher ground and staying off the roads if possible at this time. The possibility of storms also continues throughout the week.

"Move to higher ground now. Act quickly to protect your life. Heavy rainfall over the Goodwin fire scar will likely trigger flash floods in and downstream of the fire area. Heavy rains may cause dangerous flooding across roadways in Mayer near Big Bug Creek. Turn around, don't drown!” The National Weather Service (NWS) posted on its website.

"Life threatening flash floods and rock falls will occur in the Mule Canyon, Wolf Creek, and Pine Creek drainages. High water and debris will affect the Mayer-Bolada Road and Pine Flat Road. Act quickly and avoid these areas!" the NWS warned.

Several isolated lightning strikes were also reported in the area, however, no injuries have been reported so far.

The American Red Cross has opened a shelter at Sinagua Middle School, 3950 E. Butler Avenue.

The American Red Cross said the shelter will have trained volunteers who can provide advice and assistance for residents, a safe place to stay, food and water.

Flash floods near the Grand Canyon last week forced almost 200 tourists planning to visit Havasupai Reservation to evacuate.

Benji Xie, one of the tourists said he was taking photos of a beautiful waterfall when the weather suddenly took a drastic turn. Heavy rains caused water to raise high above the shallow creek that runs through Havasupai Reservation.

While some tourists were stranded on newly formed islands, others stood on top of benches, trees and caves as they sought higher ground.

"Everything is brown and muddy now," Xie said, the Salt lake Tribune reported.

Abbie Fink, a tribal spokesperson said, all the tourists were safely flown out of the canyon in a helicopter that flew out about five tourists at a time. No injuries were reported.