(Adds Puerto Rico curfew, storm forecast, winds diminished after hitting island)
SAN JUAN, Puerto Rico, Sept 20 (Reuters) - Hurricane Maria, the strongest storm to strike Puerto Rico in nearly 90 years, carved a path of destruction through the U.S. territory on Wednesday, causing widespread flooding and knocking power out across the island after killing at least nine people elsewhere in the Caribbean.
Maria, the second major hurricane to roar through the region this month, was generating sustained winds of up to 155 miles per hour (250 km per hour) when it came ashore near Yabucoa, on the southeastern end of the island of 3.4 million people.
Making landfall as a Category 4 storm on the five-step Saffir-Simpson scale, the storm ripped roofs from buildings and turned low-lying roadways into rushing debris-laden rivers.
The streets of historic Old Town in the capital, San Juan, were strewn with broken balconies, air conditioning units, shattered lamp posts, fallen power lines and dead birds. Few trees escaped unscathed. Thick branches were torn down from most and others were simply uprooted.
"The danger continues - there are flood warnings for the whole of Puerto Rico," Governor Ricardo Rossello warned residents on Twitter as the storm headed offshore. "Stay in safe places." He later imposed a dusk-to-dawn curfew for the island.
News pictures showed whole blocks flooded in areas of the capital, such as the Hato Rey neighborhood. The Miami-based U.S. National Hurricane Center (NHC) reported "catastrophic flash flooding" in portions of the island.
"When we are able to go outside, we are going to find our island destroyed," Abner Gomez, the director of the island's emergency management agency, known by its Spanish language acronym AEMEAD, was quoted as saying by El Nuevo Dia newspaper. "It's a system that has destroyed everything in its path."
Electricity was believed to be out across the island, said Pedro Cerame, a spokesman for the governor. Authorities had not yet been able to assess the extent of the damage, he said.
By 5 p.m. ET (1800 GMT), Maria's center was located just north of the island, NHC said. As is typical for hurricanes passing over hilly or mountainous terrain, Maria was considerably weakened by the time it moved offshore, with top wind speeds diminishing to 110 mph (175 kph), though the NHC said the storm was likely to regain some strength in the next day or two.
Maria was expected to pass near the northeastern coast of the Dominican Republic Wednesday night and Thursday before approaching the Turks and Caicos Islands and southeastern Bahamas on Thursday night and Friday, the NHC said. So far, it looked unlikely to threaten the continental United States.
Storm-related rainfall was expected to range from 20 to 25 inches (50 to 65 cm) on much of Puerto Rico through Friday, according to NHC.
Maria had ranked as a Category 5 storm when it struck the eastern Caribbean island nation of Dominica on Monday night with devastating force, killing at least seven people there, government officials. Two more people died in the French territory of Guadeloupe before Maria raked St. Croix, the southern-most of the U.S. Virgin Islands, early on Wednesday, causing widespread damage.
Hurricane Irma, which ranked as one of the most powerful Atlantic storms on record, also left a trail of destruction in several Caribbean islands and Florida this month, killing at least 84 people. The two other main U.S. Virgin Islands - St. Thomas and St. John - were both hard hit by Irma.
Many homes and businesses across Puerto Rico have wooden or tin roofs, cheaper building materials that also keep homes cooler in the balmy Caribbean climate, but that are no match for storms of the intensity of Maria.
"This might be a new, permanent part of our lives," said Ramon Claudio Ortiz, 71, a retired lawyer. "We're going to have to revisit our building codes."
Maria was the second-strongest hurricane ever recorded to hit Puerto Rico, behind the 1928 San Felipe Segundo hurricane, which struck the island as a Category 5 storm and killed more than 300 people.
The latest hurricanes came at a time when the island is struggling financially, grappling with the largest municipal debt crisis in U.S. history. Both its government and the public utility have filed for bankruptcy protection amid disputes with creditors.
Even though Irma passed north of Puerto Rico, it knocked out power for 70 percent of the island, and killed at least three people.
Passing just to the west of St. Croix, home to about half of the U.S. Virgin Islands' 110,000 residents, Maria damaged an estimated 65 percent to 70 percent of the island's buildings, said Holland Redfield, who served six terms in the U.S. Virgin Islands senate.
"There were a lot of homes that had lost their roofs. It was a sad sight," Redfield said in a phone interview. "I'm in a very densely populated area now, and I see a tremendous amount of confusion. A lot of trees are down."
Officials on St. Croix could not be reached for comment.
In Guadeloupe, many roads were blocked and 40 percent of the population was without power, France's overseas territories ministry said.
The island of Dominica, with a population of about 73,000, was devastated by Maria earlier in the week. Hartley Henry, principal adviser to Prime Minister Roosevelt Skerrit, said in a Facebook post on Wednesday that "the country is in a daze."
(Reporting by Dave Graham and Robin Respaut in San Juan; Additional reporting by Daina Beth Solomon in Mexico City, Richard Lough and French language service in Paris; Writing by Scott Malone and Steve Gorman; Editing by Frances Kerry and Lisa Shumaker)