Hurricane Melissa intensified to a Category 5 storm on Monday amid forecasts of “life-threatening flash flooding,” landslides, and “destructive winds” expected to impact Jamaica ahead of its landfall early Tuesday.

The storm, which is currently 145 miles southwest of Kingston, Jamaica, is expected to be the strongest to ever hit the island.

“Many of these communities will not survive this flooding,” Desmond McKenzie, Jamaica’s minister of local government, warned during a news conference on Monday. “I want to urge Jamaicans to take this seriously.”

The U.S. National Hurricane Center (NHC) warned local residents not to leave their shelters.

Seven communities were placed under emergency evacuation orders starting on Sunday night. More than 800 shelters have been opened across Jamaica, although only 1,000 people were housed in the shelters as of Monday night, McKenzie said.

Jamaican Prime Minister Andrew Holness urged Jamaicans to cooperate with evacuation orders to save lives. “You have been warned,” he said on Monday, adding: “I have been on my knees in prayer.”

Read more: What Do Hurricane Categories Actually Mean?

Fishermen along the coast of the island began to gather their boats and secure their goods on Sunday night, according to the Jamaica Observer. Dennis Gordon, a vendor at the Ocho Rios Craft Market, told the local media outlet he was bracing for the impact, pointing to the 1998 catastrophic Category 4 Hurricane Gilbert. “We [will] take a good while to come back on our feet,” he said. “We go through Gilbert and it was very, very, bad; out of food, out of water, out of light. I can only hope it don’t reach back to this because it’s coming serious.”

Category 5 storms—the highest level a hurricane can reach on the Saffir-Simpson scale and strong enough to cause “uninhabitable conditions”—often lead to roof failure, the collapse of walls, and fallen poles and trees.

Meteorologists are warning residents of the destructive winds expected to cause broad infrastructural damage and power outages across “isolated communities” starting on Monday evening. Melissa’s sustained winds have intensified to measure nearly 175 mph, per the NHC. Hurricane-force winds can be felt 30 miles from the storm’s center, while tropical-storm force winds can be felt 195 miles away.

Read more: How Are Hurricanes Named? Here’s What You Need to Know

International food organizations are preparing for the storm’s destruction. The International Organization for Migration indicated they are coordinating the distribution of food and other items, which are expected to arrive in Jamaica by Thursday. 

And more than 20 inches of rainfall are forecast to pour on the Caribbean island, causing a “life-threatening storm surge” along the southern coast through Tuesday. 

The hurricane will then reach Cuba by Tuesday evening as a Category 3 storm. Officials indicated they would be evacuating more than 600,000 people because of Melissa.

Haiti and the Dominican Republic will also face life-threatening flash flooding and landslides. Three people in Haiti have been killed as a result of the storm, which wiped out nearly 40 acres of maize. At least one person in the Dominican Republic remains missing. More than 750 homes in the country have been impacted by Melissa. Tropical storm conditions in the two countries will persist through Wednesday.