ANCHORAGE — Chris Riekena was driving with his 7-year-old son when the road beneath their car began to shake.

Riekena, an engineer with the state Department of Transportation, thought he blew a tire, so he pulled to the shoulder. Then he saw the row of streetlights above him swaying and he saw the red SUV in front of him sink into the road.

A severe earthquake, rated 7.0 on the moment-magnitude scale, ripped across the Anchorage area Friday at 8:29 a.m. Alaska time. Buildings wobbled, roads cracked and thousands lost power during the morning commute. Dramatic scenes like the one Riekena witnessed on Minnesota Drive played out across the highest populated city in Alaska.

The SUV “sank, and then it sank some more. It was a slow process — about 30 to 40 seconds,” Riekena said as a National Guard helicopter passed overhead. “In a way it was exciting and it wasn’t because it was so slow.”

The off-ramp he and his son were just driving on had buckled into a dozen massive slabs of asphalt. The driver of the red SUV walked away unharmed, Riekena said.

Alaska Gov. Bill Walker (I) issued a disaster declaration after the quake and said he spoke to President Trump Friday morning. Walker said Trump told him, “we will fix Alaska” and the federal government will spare no expense.

Walker surveyed the damage in a Blackhawk helicopter with the National Guard Friday afternoon, and noted he does not think it will be a matter of a week or two to recover. “It will take longer than that to repair,” Walker said during a news conference.

Traffic lightened as the sun set. Lines at the few open gas stations thinned. But going into the weekend, residents were apprehensive with aftershocks preventing them from feeling completely steady. The public radio station fielded multiple calls about the cleanliness of the water supply, with some residents reporting reddish-brown water coming from their faucets. Anchorage Water and Wastewater Utility reported more than two dozen mainline water breaks and the city advised residents to boil their tap water as a precaution.

After peaking above 50,000, the number of customers without power dropped to about 25,000 in Anchorage and the neighboring Matanuska-Susitna Borough Friday evening, Anchorage officials said at a news conference.

Extensive damage to the Glenn Highway, one of two roads out of Anchorage, caused police temporarily to close inbound lanes during the evening rush to allow commuters to leave the city, said Anchorage Police Chief Justin Doll. A rock slide temporarily closed the Seward Highway, the only southbound transportation corridor out of Anchorage. Officials later cleared the slide and reopened the highway.

The city opened the Egan Civic and Convention Center downtown for anyone requiring a warm place to sleep. Hettrick said about 60 people had been in and out of the center following the earthquake. City officials have no tally of how many people had been displaced.

The scene after a powerful earthquake strikes near Anchorage

An aerial view of damage on Vine Road, south of Wasilla, Alaska,after a magnitude-7 earthquake. (Marc Lester/AP)

Michelle Tobia, the manager at Bell’s Nursery in Anchorage, was in her two-story house next to the store when the earthquake hit. “The whole house was rolling is what it felt like,” Tobia said. She grabbed her dog, Daisy, a husky-Labrador mix, and ran upstairs to shelter under a door frame.

After the shaking stopped, “stuff was everywhere,” she said. “Glasses off the countertops, DVDs spewing out of the TV stand.”

The plant nursery next door was dark and the parking lot empty. Inside, a cleaning crew was picking up pots of poinsettias and toppled Christmas trees. Tobia said she was confident they would reopen by the afternoon when the lights were back on and employees had a chance to clean up their own homes.

Police officers were dispatched across the region to handle “multiple situations,” the department said. A journalist with the news station KTVA shared a photo of the damage in that newsroom, where pieces of the ceiling had apparently fallen on desks and the floor. The Minnesota Drive off-ramp near Ted Stevens Anchorage International Airport drew a string of spectators.

Keri Scaggs and her neighbor RieAnn Fullwood snapped selfies in front of the collapsed road as a third neighbor, still in her bathrobe, waited for them in the car. Scaggs clutched a bottle of Kentucky straight bourbon whiskey, while Fullwood snuggled her cat. The pair fled their cabins in the Spenard neighborhood after the tsunami warning.

“I grabbed the essentials,” Scaggs said. “Birth certificate, passport and Pappy Van Winkle,” she said, cradling the bottle in the crook of her elbow.

The Federal Aviation Administration had declared a ground stop at the airport after the earthquake. At 11:30 a.m. in Anchorage, the FAA said it had begun letting flights depart from the airport, but the ground stop was kept in place for arrivals.

Samuel Shea, the science operations officer at the National Weather Service in Anchorage, said his drive from the office to his home in South Anchorage, which usually takes around 10 minutes, was 40 minutes on Friday after the earthquake.

“It was terrifying,” Shea said. “I mean, we have magnitude fives, sixes — we deal with earthquakes all the time, and this was the strongest I’ve ever felt, and the most terrifying minute of my life.” Several hours after the initial quake, aftershocks were still rolling across the region, and “it just stops your heart” when they happen, he said.

The National Weather Service in Anchorage briefly suspended operations on Friday morning after the tsunami warning was issued. All of the office’s duties were handed over to the Fairbanks office, and the meteorologists and staff evacuated. Operations resumed at the Anchorage office after the warning was canceled.

The earthquake hit as students were on their way to school, about 30 minutes before classes would start. The Anchorage School District canceled Monday and Tuesday classes while it assessed damage to its facilities.

“Take care of your families,” the district’s superintendent, Deena Bishop, wrote on its website.

The University of Alaska Anchorage closed its campus on Friday after the earthquake, urging all nonessential personnel to leave and warning people to stay away from the campus.

Chancellor Cathy Sandeen posted online that while the university sustained some damage, there was “no word of injuries, thankfully.” She also posted a photograph showing the damage to one of the rooms on campus, which was littered with ceiling tiles that had fallen down.

The U.S. Geological Survey estimates a low probability of fatalities from the earthquake. Estimated economic losses are most likely between $100 million and $1 billion, which is an “orange alert,” according to the survey’s algorithms. “Past events with this alert level have required a regional or national level response,” the center said on its website.

Friday’s quake occurred on a fault line between the Pacific and North American tectonic plates, the USGS said. The rupture between the faults occurred in an area where the Pacific plate is moving underneath Alaska. Anchorage was severely damaged in March 1964 by the Great Alaska Earthquake, a 9.2-magnitude quake with its epicenter about 75 miles east of the city. That quake, which lasted for about 4½ minutes, was the most powerful earthquake recorded in U.S. history. It destroyed a major part of downtown Anchorage and caused a tsunami that ravaged towns on the Gulf of Alaska and beyond.

On Friday afternoon at the Brother Francis Shelter, several dozen clients and volunteers talked quietly or stood outside and smoked in the icy parking lot. David Rittenberg, program director, said all 240 beds were available for the night. The shelter “was built to withstand earthquakes.” Rittenberg said.

Rittenberg said the power went out for about seven hours, but the quake did not affect the shelter’s water supply and a gas line that runs through the property was undamaged. The violent shaking interrupted breakfast at the neighboring soup kitchen, Bean’s Cafe, but everyone had ham sandwiches and chips for lunch and would be getting full dinners.

Ken Johnson, a client and volunteer at the shelter, said he had just finished breakfast and was coming out of Bean’s Cafe when the shaking started.

“I’ve felt these in California, so I knew what was happening,” Johnson said. “I was going out to smoke anyway, so I got out the door quick and then held onto a pole.”

Berman and Fritz reported from Washington. Dan Lamothe contributed to this report.