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

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.

Powerful Hurricane Erin has undergone a period of astonishingly rapid intensification — a phenomenon that has become far more common in recent years as the planet warms. It was a rare Category 5 for a time Saturday before becoming a Category 4, churning through the Atlantic Ocean north of the Caribbean.

Hurricane Erin could bring dangerous seas as it grows near the Bahamas - Nation and World News | Hawaii Tribune-Herald