Hurricane Erin weakened to a Category 3 hurricane Sunday as its outer bands continued to lash the Virgin Islands and Puerto Rico with heavy rains and tropical-storm force winds.

After exploding in strength at a historic rate this weekend, Hurricane Erin is now a sprawling Category 4 storm churning in the Atlantic. The storm’s enormous footprint is becoming the biggest concern as it threatens to drive life-threatening rip currents and towering waves toward the eastern US coastline and Bermuda.