Hurricane Erin forced tourists to cut their vacations short on North Carolina’s Outer Banks even though the monster storm is expected to stay offshore after lashing part of the Caribbean with rain and wind on Monday.

A video shared from Puerto Rico shows foggy conditions as heavy rain fell and winds whipped across the island as Hurricane Erin spun off to the north.

Tropical Storm Erin is expected to become a strong hurricane by the end of the weekend. How strong will it be and will it impact the U.S.?

Storms that ramp up so quickly complicate forecasting and make it harder for government agencies to plan for emergencies. Hurricane Erick, a Pacific storm that made landfall June 19 in Oaxaca, Mexico, also strengthened rapidly, doubling in intensity in less than a day.