Evacuations are underway and time is running out for Floridians to prepare for Tropical Storm Helene, which threatens to hit as the strongest storm to make landfall in the United States in over a year.

A hurricane watch and warnings of storm surges up to 15 feet high were issued Tuesday for almost all of Florida's western coastline as Tropical Storm Helene formed over the Caribbean Sea and heads toward the Gulf Coast.

Helene is expected to rapidly intensify into a major and massive hurricane with 115-mph winds by the time it makes landfall Thursday.