Hurricane Erin has strengthened to a Category 4 as it moves toward the US East Coast, threatening life-threatening conditions. The storm, initially a Category 5, is impacting the southeastern Bahamas and Turks and Caicos with heavy rainfall and has caused significant power outages in Puerto Rico. Authorities are taking precautions, especially in areas like the Outer Banks, where evacuations are underway and warnings for dangerous surf are in place. Residents are advised to prepare for quick changes in the storm’s movement.