Hurricane Erin is churning slowly toward the eastern U.S. coast and stirring up waves that already have forced dozens of beach rescues, days before the biggest storm surges are expected.

Erin’s surf and storm surge could cause erosion along sections of the Florida and East Coast and shapes up as potentially worse for North Carolina’s barrier islands, which are under mandatory evacuation orders ahead of the four feet of storm surge and 20-foot offshore waves Erin is expected to bring.