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.

Beaches are being closed at some locations along the US East Coast as Hurricane Erin threatens rip currents from Florida to New England.

Additional strengthening is expected as the storm is forecast to “remain a large and dangerous major hurricane through the middle of this week,” the National Hurricane Center said.

Hurricane Erin has been downgraded to a Category 3 hurricane but is gaining in size and raising the risk of life-threatening surf later this week along the U.S.

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.?

Hurricane Erin strengthened 85 mph in 24 hours to a 160 mph Category 5 hurricane putting in fourth place for rapidly intensifying storms.