Rebuilding after the strongest hurricane to hit cash-strapped Puerto Rico in nearly a century is going to be a "titanic effort," said the U.S. territory's sole representative in Congress.

In a telephone interview from San Juan with CNBC on Thursday, Rep. Jenniffer Gonzalez-Colon provided a first-hand account of the devastation from Hurricane Maria.

"This is not the same island," the Republican congresswoman told "Squawk Box." "There are no trees. There are no palm trees."

"Most of the houses lost part of the windows [and] doors," she added. "People with wooden houses, of course, didn't resist it — this type of environment like never before."

Less than two weeks after getting sideswiped by Hurricane Irma, Maria made landfall on Puerto Rico Wednesday as a Category 4 hurricane with winds of 155 mph.

Maria put the entire island in the dark.

Gonzalez-Colon said Puerto Rico needs help re-establishing power. "One of the problems that we've got is once the power is out there water pumps are not [working]."

Even before the storms though, the electric grid was crumbling. Many believe it'll take weeks, if not months, to restore power.

Puerto Rico's recovery could be complicated by its mounting debts. Both the island's government and the public utility there have filed for bankruptcy protection.

Meanwhile, more than 12,000 people were in shelters as of Wednesday, according to Gonzalez-Colon. She expects that number to go up in the coming days.



With widespread flooding and downed power lines, it's dangerous to venture outside, she said, adding rescue teams were still searching for storm victims. "FEMA is already on the island with more than 400 rescue teams from different federal agencies."

Even as Maria pulled away from Puerto Rico, more rain was expected there Thursday. "It's going to continue to rain today and the days to come," warned Gonzalez-Colon.

As for the hurricane's path, Maria was passing near the Dominican Republic. Turks and Caicos and the southeast Bahamas could feel the fury of the storm by the evening.