A little more than two years after a hurricane-like spring storm tore a wide opening at Norton Point beach in Edgartown, the breach has begun to change, migrating eastward toward Chappaquiddick. As a result the tides in Katama Bay and the Edgartown harbor have begun to moderate, which may mean some relief for sailors and boaters this summer.

Before the storm two years ago, Norton Point beach was a two-mile barrier beach that connected Katama to Chappaquiddick. Historically the beach has breached about every 10 or 15 years, but at the time of the storm there had not been a breach for nearly 30 years.

On April 14, 2007, all that changed in a ferocious northeast storm that held on for days.

Following the storm the new opening quickly grew to almost a mile in width; at its center was a deep channel with strong currents running through it.

There were dramatic changes in Katama Bay. Sandbars appeared where previously there had been none; clam flats shifted, some disappearing altogether. Tides became unpredictable and currents increased dramatically in the Edgartown harbor, putting small sailboats at risk and adding stress to the Chappaquiddick ferry, a three-car barge that plies the narrow channel just off Memorial Wharf. The owner of the ferry was forced to increase the horsepower of his diesel engines to cope with the change.

Fishermen had to adjust their gear.

And of course Chappaquiddick was a true island, no longer accessible in an over-sand vehicle.

But now those who use the harbor and the beach confirm that the situation has changed for the better. “The opening is getting smaller. It used to be a mile wide. It isn’t a mile now, maybe a couple hundred yards,” said Paul Schultz, who has worked for the Trustees of Reservations on Chappaquiddick for 18 years.

Mr. Schultz has kept measurements of the beach. Just after the breach opened, Mr. Schultz said it was exactly a one-mile drive from the Norton Point opening to the left fork parking lot. “I did the run the other day. It was 1.6-mile drive. The beach has moved six-tenths of a mile east and the other side of Norton Point beach is underwater,” he said.

There is other evidence. A mooring and buoy that were placed at the edge of the opening on the Chappaquiddick side two years ago no longer mark the same spot. The opening has not only moved east of the buoy, but the point has migrated east of it as well. The buoy was put out by the sheriff’s department; the mushroom anchor that holds it is so deeply buried in new sand it cannot be removed.

From the air, the change is vivid, with the barrier beach on the eastern side forming a large comma as sand builds up around it.

“What is happening is what everyone is expecting,” said Chris Kennedy, the longtime Islands regional director for the Trustees who is based on the Vineyard. “The opening is migrating eastward toward Chappaquiddick, and we’ve seen this over the last six months. The opening isn’t increasing, it is getting narrow,” he said.

Mr. Kennedy said the Chappaquiddick side of the beach remains low and is still washed over by tides. He said the sand likely will not be stable enough to allow public vehicular access this summer. But he said the other side is much better.

Norton Point Beach and its opening to the sea have been tracked for centuries. The Gazette carried stories about breaks in the beach in 1856, 1886, 1938 and 1954. There were also small breaks late in the 1970s and a short one that came and went with Hurricane Bob.

Though there are a number of Edgartown waterfront experts who can recall the various breaches over the years, no one alive recalls currents as strong as they were for the last two summers, and no one can remember an opening as big as this one. Strong currents wreaked havoc with small boaters using the harbor, and the children’s sailing program run by the Edgartown Yacht Club was moved out of the harbor to the area off the Chappaquiddick Beach Club for safety reasons.

The currents have become more changeable.

Robert Gilkes, a captain on the Chappaquiddick ferry, agreed that currents appear to be lessening. Mr. Gilkes said one day last week he operated the three-car ferry as though there was no opening at all. “It was a straight run across,” Mr. Gilkes said. But currents in the harbor kicked up again a few days later when the wind picked up. “We had some heavy equipment on the ferry, and the current pulled us down by the Mad Max dock. When the tides are strong, we still make a big swing,” the ferry captain said.

Edgartown harbor master Charlie Blair welcomes the news of the changing breach. “From my point of view, everybody is talking about the current. That means to me there is less current. The yachtsmen and fishermen are hoping it is all true.”

The Katama side of Norton Point Beach remains a popular place among swimmers and fishermen, Mr. Kennedy said.

“The Edgartown side was very popular for the over-sand vehicles, to the point that we sold $195,000 worth of permits last year,” he said, adding: “Those permits were used on the Edgartown side almost exclusively.”

This summer those beachgoers will likely find even more sand for roaming, surfcasting and picnicking.