Hurricane Erin is causing dangerous conditions at beaches along the Jersey Shore, NYC and Long Island, where some could see coastal flooding.

A rip current, which flows out toward the ocean, can quickly pull a swimmer away from the shore. Rip currents usually reach a speed of 1 to 2 feet per second, but some can clock in at 8 feet per second, which is faster than an Olympic swimmer, according to the National Oceanic and Atmospheric Administration.