PORTLAND (AP) – Two powerful storms in May are being blamed for increasing the danger of riptides and causing beach erosion along the Maine coast.

Winter storms every year drag sand away from New England’s beaches and deposit it offshore. In the summer, waves slowly bring the sand back to the beaches.

The May storms were essentially winter storms, and they put the natural cycle behind schedule, said Stephen Dickson, a marine geologist with the Maine Geological Survey.

As a result, beachgoers will notice less sand on the beaches than usual for this time of year. He said there may also be underwater sandbars and troughs in areas that are usually flat.

People in waist-deep water may find themselves suddenly over their heads when they step into a trough, he said. Riptides – fast currents that rush seaward after incoming waves pile up on the beach – often occur in such troughs, he said.

The threat of riptides was highlighted last Monday when two Massachusetts men drowned at Hampton Beach, N.H., after trying to save a 10-year-old boy who had been pulled into the ocean by a strong current in waist-deep water. The boy was rescued, but Carlos Reyes, 35, of Marlboro, Mass., and Alex Tapia, 26, of Worcester, Mass., drowned.

Riptides at that section of the beach have been especially severe this season because the May storms apparently changed the beach’s underwater profile, said Sgt. Cheryl Clancy of the New Hampshire Marine Patrol.

The U.S. Lifesaving Association estimates that more than 100 people a year drown because of riptides.

On Maine beaches, the majority of lifeguard rescues are the result of riptides, said Tim Hall, a regional manager for the Maine state park system.

“Across the U.S., it is the single most dangerous phenomenon along the coast,” he said.

At Scarborough Beach State Park, veteran lifeguard Joe Doane said the beach has more underwater ruts and holes than usual this summer.

On an average summer day at the beach, he said, about 10 people get caught in riptides. He can recognize a riptide has formed because the water is foamy and discolored with sediment.

“It looks like somebody is at the bottom of the ocean with a blender,” he said. “You can visually see it. And you look for people. You get the people before they go under.”