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.

Despite this, the US National Hurricane Center (NHC) says Erin is growing in size, with tropical-storm-strength winds extending 205 miles from its centre. Storm-related hazards, including flash flooding and landslides, are expected in the Virgin Islands and Puerto Rico.

An eyewall replacement cycle is underway within Hurricane Erin as the monster storm continues to barrel across the Atlantic while bringing gusty winds and rain to Puerto Rico and the Virgin Islands after rapidly intensifying into a catastrophic Category 5 hurricane over the weekend.

Tropical Storm Erin on Wednesday continued to push west through the Atlantic with it forecast to become the season’s first hurricane, growing to major hurricane strength by the weekend,

After completing an eye wall replacement cycle, Hurricane Erin has now restrengthened to a Category 4 hurricane. Erin had max sustained winds of 130 mph, the National Hurricane Center said in an update on Sunday evening.