Melissa is expected to strengthen from a tropical storm into a major hurricane and bring "catastrophic" flash flooding and landslides to Jamaica, Haiti and the Dominican Republic

Melissa has already proven to be deadly. Haiti's civil protection agency says three people have already been killed in the country, per the New York Times. Two deaths were the result of a landslide in Port-au-Prince, while the third was caused by a falling tree on the country's south coast in the town of Marigot.