Parts of North Carolina's Outer Banks are under mandatory evacuation orders, as the National Hurricane Center warns that Hurricane Erin could bring tall waves topping 15 to 20 feet.

The monster storm intensified to a Category 4 with 140 mph (225 kph) maximum sustained winds early Monday while it started to lash the Turks and Caicos Islands and the southeast Bahamas, according to the U.S. National Hurricane Center in Miami.

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

Maximum sustained winds have increased to near 140 mph, with higher gusts. Erin is a Category 4 hurricane on the Saffir-Simpson Hurricane Wind Scale. Some additional strengthening is expected today. Erin will remain a dangerous major hurricane through the middle of this week.