“We’re not out of the woods yet,” Mr Mitchell warned at a news conference on Monday. Grenada has also experienced several power outages, affecting access to communications and government updates.
According to the NHC's latest update, the hurricane's maximum sustained winds are expected to be around 150 mph (241 km/h) as it moves west.
A hurricane watch has been issued for Jamaica, meaning the area is likely to experience hurricane conditions through Wednesday.
“This is not a joke,” said Ralph Gonçalves, the prime minister of Saint Vincent and the Grenadines, reminding people of the devastation caused by past hurricanes in the Caribbean.
Mr Gonsalves addressed the nation from his official residence, saying he was seeking refuge in the basement.
“The roof, especially the older parts of the roof, may not be able to withstand 150 mph winds. I'm getting ready to go downstairs,” he said.
Beryl's power fluctuated.
The hurricane weakened slightly before being upgraded to a Category 4 on Monday.
The NHC warned that while intensity fluctuations are likely to continue, some areas of the Windward Islands should prepare for “potentially catastrophic wind damage.”
The report said Saint Vincent and the Grenadines and Grenada were most at risk of damage.
The hurricane shelter opened at 6 p.m. local time (10 p.m. GMT) on Sunday.
