Hurricane Fiona made landfall on the southwestern coast of Puerto Rico at 3:20 p.m ET on Sunday. There have been reports of dangerous flash flooding and a full power outage.

Fiona had maximum sustained winds of 85 mph and was moving west-northwest at 8 mph with winds that extend as far as 140 miles from its center, The National Weather Service reported.

"If you're out and about, it's time to go home and stay put until this storm passes," Jamie Rhome, the acting director of the National Hurricane Center, said in a briefing.

The rain has already reached significant flooding levels, yet the most dangerous part of the storm is expected to hit Sunday through Monday.

As of Saturday night, 640 residents were seeking shelter.

Forecasters say there could be around 25 inches of rain produced with the possibility of causing landslides and treacherous roads.

There are around 1.5 million customers without electricity as of Sunday afternoon, according to power-outage tracking website Poweroutage.us.

"It's time to take action and be concerned," said Nino Correa, Puerto Rico's emergency management commissioner.

President Joe Biden on Saturday declared a state of emergency for Puerto Rico and has authorized disaster relief along with federal assistance for response efforts.

The Dominican Republic could be hit by Fiona on Sunday night and continue into Monday.

Fiona could threaten Bermuda as a hurricane, according to experts.