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.

A video shared from San Juan, Puerto Rico, shows the city starting to feel the effects of Hurricane Erin on Saturday, Aug. 16.

U.S. shores are unlikely to see a direct hit, but a strong offshore hurricane can produce massive and dangerous waves well away from its center.

Hurricane Erin has strengthened into a Category 2 storm as it approaches Puerto Rico and the Virgin Islands, bringing heavy rains that could cause flooding and landslides.

Hurricane Erin was downgraded to Category 3 early morning on Sunday, Aug. 17, per the National Hurricane Center. However, the tropical storm is still expected to bring 'life-threatening' conditions to the beaches along much of the east coast of the U.

As of 5:00 p.m. AST on Sunday, Erin’s center was positioned approximately 275 miles northwest of San Juan, Puerto Rico, tracking west-northwest at 13 mph. Although no longer directly affecting the area, the storm’s outer bands are still delivering heavy rainfall, dangerous marine conditions, and life-threatening surf along coastal areas.

Hurricane Erin has exploded into a Category 5 hurricane in the Caribbean, according to the National Hurricane Center. The storm is currently north of Anguilla, with winds of 160 mph.

Hurricane Erin weakened to a Category 3 hurricane on Sunday, its outer bands lashing the Virgin Islands and Puerto Rico, as forecasters warned the storm was rapidly growing.

While the category 4 storm is not expected to make landfall on the U.S. east coast, it will have an impact nonetheless. Dangerous high surf and rip currents are expected from Florida to New England throughout the week.