The Hurricane Center said that Hurricane Melissa was moving slower than expected over the Caribbean, putting Jamaica at greater risk of catastrophic flooding and storm surge. Slower storms can also dump large amounts of rain over a longer period, pushing more water from the coast further inland.

Jamaica is expected to be in the storm's eyewall, which refers to the band of dense clouds surrounding the eye of the hurricane. The eyewall generally produces the fiercest winds and heaviest rainfall, according to Deanna Hence, a professor of climate, meteorology and atmospheric sciences at the University of Illinois Urbana-Champaign.

Jamaica residents were warned Monday to "seek shelter now," as Melissa, a strong Category 5 hurricane, neared landfall on the Caribbean island nation.

The news “underscores the profound ecological toll that Hurricane Melissa will have on Jamaica’s biodiversity,” said one expert on the island.

"It is more than kind of distressing because you don't know when and you don't know how," said Ewan Simpson, who lives in Jamaica.