“There has been nothing like this,” said Ramón Lopez, a military veteran who was holding back tears outside his neighborhood in Guaynabo, on the northern coast near San Juan, the capital. “It was the fury. It didn’t stop.”
Such was the sentiment across the island as the barrage of howling gusts and pounding rain did not cease from the early morning until evening.
Francisco Ramirez, 23, weathered the storm inside the convenience store of a gas station in Guaynabo. As a security guard at the station, he was scheduled for the 8 p.m. shift on Tuesday, hours before Maria hit. He sat behind a counter while the storm raged outside and water seeped in beneath the doors. Winds peeled off the aluminum roof piece by piece throughout the night, and knocked over several gas pumps.
“It felt like a tornado, as if the roof was going to come off,” Mr. Ramirez said.
Thousands of residents fled the winds and rain and hunkered down in stronger buildings. More than 500 shelters have been opened in Puerto Rico, but Gov. Ricardo Rosselló said he could not vouch for the storm-worthiness of those structures.
About 600 people took refuge in one of the biggest shelters, the Roberto Clemente Coliseum in San Juan. Witnesses said that the arena’s roof had come off and that the shelter lacked electricity and running water.
“It’s looking ugly, ugly, ugly over here,” Shania Vargas, a resident of Carolina who had taken shelter in the arena, said in a telephone interview.
Mayor Carmen Yulín Cruz of San Juan remained at the shelter with residents as the hurricane struck. She told people there that there had been widespread flooding in the city, and said in a video posted to Twitter that “as uncomfortable as we are, we are better off than any other place.”
Elsewhere in the capital, tree trunks and electricity poles had snapped like twigs, obstructing major highways and winding mountain roads alike. If an exit was not blocked by foliage, then it was flooded. Power lines thrashed in the high winds. The commercial Roosevelt Avenue had water up to the waist.
Metal gates in affluent neighborhoods like Caparra had been crumpled like cardboard, while makeshift trails leading to wooden houses in the barrios of Guaynabo had been made impassable by fallen trees.
Smaller towns and more rural areas, many full of wooden houses with zinc roofs, were difficult to reach after the storm, but widespread damage was reported. Mayor Félix Delgado of Cataño, on the northern coast, told a San Juan radio station that the storm had destroyed 80 percent of the homes in the Juana Matos neighborhood, which had been evacuated.
Photos and videos posted on social media showed severe flooding in the central areas of the island. Rivers overflowed and their waters rushed through the narrow streets, taking some homes with them.
Brock Long, the head of the Federal Emergency Management Agency, said that the United States Virgin Islands and Puerto Rico had very fragile power systems and that electricity was expected to remain out for a very long time.
Much of Puerto Rico lost power after Hurricane Irma passed just north of it this month, exposing the island’s doddering infrastructure and the severe challenges it faces amid a worsening economic crisis. Electrical power, produced by the state-owned Puerto Rico Electric Power Authority, or Prepa, has long been a headache for residents, who have come to distrust the flickering grid even in normal conditions.
Efforts by Prepa to fix lines and restore power after Irma will almost certainly have been undone by Maria, and the question of how a debt-ridden commonwealth will pay for comprehensive repairs is sure to confound its leaders long after the storm dissipates.
Potable water was also affected by the storm, but the authorities could not yet say just how much damage had been done. Elí Díaz Atienza, president of the Aqueduct and Sewer Authority, said that the agency’s communications systems had gone down and that he was not able to check on plants and offices.
The gates of La Plata dam in Bayamón and the Carraízo dam in Trujillo Alto, both on the northern coast, were opened to avoid flooding in the nearby areas. The authority had begun emptying the reservoirs several days ago in anticipation of heavy rain.
Mr. Rosselló said on Twitter that he had urged President Trump to declare Puerto Rico a disaster zone. Mr. Trump declared an emergency in the commonwealth on Monday, and ordered federal assistance in the hurricane response. But a disaster declaration would escalate that help.
Mr. Trump called the hurricane “a big one” at a meeting in New York with King Abdullah II of Jordan. “I’ve never seen winds like this. Puerto Rico, you take a look at what’s happening there. It’s just one after another,” he said.
Other islands hit by Hurricane Maria before it made landfall on Puerto Rico were still struggling to regroup. Seven deaths had been confirmed on Dominica, where the hurricane hit Tuesday, and the toll was likely to rise, according to Hartley Henry, an adviser to Prime Minister Roosevelt Skerrit. Housing was severely damaged and all public buildings were being used as shelters, he said.
On Puerto Rico, even the concrete walls of some condominiums in San Juan had been blasted away, leaving living rooms and kitchens exposed. Outdoor basketball courts were swimming pools. Traffic lights had been knocked down and were now part of the obstacle courses of roadways. Zinc-roofed structures were destroyed, as were windows and glass doors.
“This looks like a different country,” Marimar de la Cruz, an educational consultant, said as she viewed the destruction in Hato Rey, a San Juan neighborhood.
Earlier on Wednesday, Mr. Rosselló said that the island had updated its building codes around 2011. Recent structures have been built to withstand storms, but many traditional dwellings, the governor said, “had no chance.”
Still, Mr. Rosselló offered words of hope.
“There is no hurricane stronger than the people of Puerto Rico,” he said. “And immediately after this is done, we will stand back up.”