Hurricane Erin is marching north, lashing North Carolina's Outer Banks with rough waves and coastal flooding, and bringing a threat of dangerous waves and potentially deadly rip currents to the East Coast. Due to the high surf and rip current risk, New York City is extending its swimming ban.

North Carolina expects coastal flooding from massive waves, tropical-storm-force winds and tidal and storm surges for much of the state shoreline, especially the Outer Banks, as well as life-threatening rip currents for most of the week, Stein said, adding, "No one should be in the ocean."

Beachfront property owners braced for the worst amid predictions of a storm surge of up to 4 feet and significant coastal erosion. Powerful waves of 15 to 20 feet are expected to slam beaches, especially in North Carolina, for 48 hours or more as the hurricane crawls northward offshore through at least Thursday.