Emergency officials in Puerto Rico continue to monitor the damaged Guajataca Dam located in the northwestern part of the island as it remains at risk for failure following the devastating impacts of Hurricane Maria.
On Sunday, the National Weather Service in San Juan extended the flash flood warning until 2 p.m. local time for the regions of Isabela and Quebradillas, located downstream of the Guajataca River.
Emergency officials evacuated tens of thousands on Friday when it became apparent the dam could collapse under the weight of the additional water brought by Maria.
Puerto Rico Gov. Ricardo Rosselló told CNN late Sunday that the dam suffered infrastructure damage and is releasing water.
"Right now, as it stands, a couple of hours after I went through Isabela, part of the dam did break [and] it is releasing water," Rosselló said. "And that dam is partly concrete, partly soil. So as water runs through, erosion starts having its toll on the dam and my concern is at some point it'll break."
Ramón Rosario, the secretary of public affairs and public policy in Puerto Rico, said an American engineer was scheduled to visit the dam, according to Radio Isla 1320.
In addition to the worries about the dam, the entire island, home to more than 3.4 million people, remains without power. It could be months before power is fully restored.
The U.S. Department of Energy said power restoration efforts in critical areas have begun in Puerto Rico as well as the U.S. Virgin Islands.
The agency is coordinating with the Federal Emergency Management Agency (FEMA), the Puerto Rico Electric Power Authority and mutual aid crews from New York.
There are currently over 10,000 federal staff members helping with recovery in the U.S. Virgin Islands and Puerto Rico and more are on the way, according to FEMA.
FEMA administrator Brock Long is expected to visit both Puerto Rico and the U,S. Virgin Islands on Monday.
There are +7,000 federal staff (575 @fema) on the ground in USVI and PR, supporting response to #Maria & #Irma. More on the way. #TeamEffort https://t.co/lQqwy7ah4U
— Eileen Lainez (@FEMAspox) September 24, 2017
Sen. Bill Nelson, a Democrat from Florida, said Monday morning that he is calling for additional support to be sent to Puerto Rico to help with rescue and construction operations.
Am calling on U.S. military to send additional search & rescue, medical and construction teams to Puerto Rico in wake of Maria.
— Bill Nelson (@SenBillNelson) September 25, 2017
As Maria tracked over the island, it unleashed rainfall totals of more than 20 inches (508 mm) in many areas, which helped trigger record flooding.
Maria was the first Category 4 hurricane to make landfall in Puerto Rico in 85 years, while Rosselló said the storm was the worst hurricane in a century for the island.