Evacuations were underway as the slow-moving Category 5 storm -- potentially the biggest ever to hit Jamaica -- crept forward.

Four deaths -- three in Jamaica and one in Haiti -- have already been blamed on the deteriorating conditions but officials were concerned that many people were ignoring pleas to get to safety.

In the worst-hit areas, said Jamaican Prime Minister Andrew Holness, "I don't believe there is any infrastructure within this region that could withstand a Category 5 storm."

"For Jamaica it will be the storm of the century so far," Anne-Claire Fontan, at the World Meteorological Organization, said.

The US National Hurricane Center (NHC) reported early on Tuesday that Melissa was about 115 miles (185 kilometers) from the Jamaican capital Kingston, reaching maximum wind speed of 175 miles (280 kilometers) per hour.

Surging ocean, together with rainfall expected to be measured in feet not inches, will likely trigger deadly floods.

But officials were worried that many had refused to heed evacuation calls.

Local government minister Desmond McKenzie said late Monday that many of the island's 880-odd shelters remained empty.

"I want to urge persons... to get to high ground as quickly as possible," he said.

Roy Brown, a plumber and tiler, told AFP he'd had bad experiences in government shelters during previous hurricanes and was "not moving."

"I don't believe I can run from death," he said.

- Lumbering giant -

Melissa was forecasted to reach the nearby eastern end of impoverished Cuba late Tuesday after pummeling Jamaica.

The Jamaican Red Cross, which was distributing drinking water and hygiene kits ahead of infrastructure disruptions, said Melissa's "slow nature" made the anxiety worse.

The hurricane was creeping along at human walking pace, meaning there will be no quick relief once it hits, likely lingering over the tropical island renowned for tourism, sprint star Usain Bolt and reggae.

"You anticipate that maybe within four hours it would be gone... but Melissa is not looking like that," Red Cross spokesperson Esther Pinnock told AFP.

Up to 40 inches (one meter) of rainfall were forecasted, with flash flooding and landslides also expected in Haiti, the Dominican Republic and Cuba.

A "life-threatening" storm surge is likely along Jamaica's southern coast, with waters potentially rising 13 feet (4 meters), along with "destructive waves," the NHC said.

There were fears that Melissa will wreak devastation on par with historic hurricanes, including 2017's Maria or 2005's Katrina, which left indelible impacts on Puerto Rico and the US city of New Orleans, respectively.

Scientists say human-driven climate change has exacerbated massive storms, increasing their frequency.

- Global warming -

Meteorologist Kerry Emanuel said global warming was causing more storms to rapidly intensify as Melissa did, raising the potential for enormous rains.

"Water kills a lot more people than wind," he told AFP.

The last major hurricane to impact Jamaica was Beryl in July 2024 -- an abnormally strong storm for the time of year.

"Human-caused climate change is making all of the worst aspects of Hurricane Melissa even worse," said climate scientist Daniel Gilford.