(TNND) — Hurricane Erin is rapidly intensifying as it makes its way above the northeastern Caribbean on Saturday, leveling up from a tropical storm to a Category 5, the National Hurricane Center said.

Erin has become a rare and “catastrophic” storm as it rapidly powered up from a tropical storm in a single day. While the hurricane’s center was not expected to hit land, it has threatened to dump flooding rainwater as it continues to grow.

Director of the National Hurricane Center in Miami, Mike Brennan, said Erin has sustained winds of 100mph (160 kph) to 160 mph (257 kph) in just nine hours. This measurement is an 85 mph increase from the 75 mph winds recorded at 11 a.m. on Friday.

“We expect to see Erin peak here in intensity relatively soon,” Brennan said in an online appearance.

Winds are expected to strengthen, powered by the warmer than normal Atlantic throughout Saturday.

Erin was close enough to affect nearby islands and tropical storm watches were issued for St. Martin, St. Barts and St. Marteen. The heavy rainfall in some areas could lead to flash flooding, landslides and mudslides, the Hurricane Center warned.

U.S. coastal areas including North Carolina’s Outer Banks, Long Island, New York, and Cape Cod Massachusetts face a higher risk of potentially severe tropical storm or hurricane weather as opposed to much of the Southern Atlantic, mid-Atlantic and norther New England coasts, AccuWeather said.

The Atlantic hurricane season runs from June 1 to Nov. 30 and Erin is the fifth named storm thus far. Additionally, it is the first to become a hurricane.

The U.S. government has deployed more than 200 employees from the Federal Emergency Management Agency and other aid agencies to Puerto Rico as a precaution.

Forecasters have issued a flood watch for the entire territory from Friday into Monday.

On Friday, the U.S. Coast Guard closed six seaports in Puerto Rico and two in the U.S. Virgin Islands to all incoming vessels unless they received prior authorization.

Officials in the Bahamas said they have prepared shelters as a precaution and urged the public to remain vigilant.

“These storms are very volatile and can make sudden shifts in movement,” said Aarone Sargent, managing director for the Bahamas’ disaster risk management authority.

Editor’s Note:The Associated Press contributed to this report.