(CNN) - Canceled. Rescheduled. As Hurricane Arthur gyrates up the East Coast, beachfront Fourth of July celebrations are falling flat -- and that could save lives, if it keeps revelers out of the water.The Atlantic storm graduated early Thursday from a tropical storm to become the first hurricane of the season, the National Weather Service said.
Its maximum sustained wind speeds reached 75 mph as it spun off the coasts of Georgia and South Carolina, heading toward the North Carolina shoreline.
Even if Arthur goes down in weather history as a softie of a cyclone, it could still shake some lethal tricks out of its sleeve: Rip currents.
The rapid flows of water from the shore back out to the ocean are the biggest danger at the beach, the weather service says. They lurk beneath the waves and are hard for swimmers to spot.
Tropical cyclones killed six people in 2009, the National Weather Service said -- and all of them drowned in large waves or rip currents produced by their storm surges.