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.

Hurricane Erin has maintained 125 mph winds as it brought damaging impacts to parts of the Puerto Rico and the U.S. Virgin Islands on Sunday. The National Hurricane Center says the storm could undergo another intensification episode again becoming a Category 4 hurricane.