Hurricane Erin strengthened back into a Category 4 storm as U.S. officials warned of dangerous rip currents this week.

Parts of North Carolina's Outer Banks have been placed under a tropical storm and storm surge watch as the still-growing, powerful, major Hurricane Erin begins a northward turn Tuesday that could send hazardous surf,

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.