The mayor of Puerto Rico's capital thinks the island's 3.5 million residents will likely be without power for as long as six months.

"The San Juan that we knew yesterday is no longer there," San Juan Mayor Carmen Yulin Cruz told MSNBC late Wednesday. "We're looking at 4 to 6 months without electricity."

As of Wednesday afternoon, 100 percent of the U.S. territory was without power after Category 4 storm winds and substantial flooding ripped through the Caribbean island. Intense flooding has turned city streets into makeshift rivers and many cities do not have water.

"I'm 54 years old. I've never seen devastation like this one. The human spirit is going to have to rise up real high," Yulin added.

It's the first time in 85 years that a hurricane of this level has hit the island, which is similar to the size of New York's Long Island.

Storm surge is expected to hit up to nine feet in coastal regions of Puerto Rico and the U.S. Virgin Islands. Puerto Rico can expect between 12 to 35 inches of rain depending on where they live.

As of 2 p.m. EST Wednesday, the storm had been downgraded to a Category 3 storm with 155 mph winds reported. The National Hurricane Center said the hurricane's winds will continue to lessen through the day, before it heads northwest toward other Caribbean islands.

Maria could gain strength while traveling over the warm tropical waters, but is not expected to turn west toward the U.S. mainland.