Four people were pulled from Casco Bay after their sailboat overturned in a squall Saturday afternoon.

John Tracy, captain of the Casco Bay Lines ferry Aucocisco, said he spotted the small boat about 4:30 p.m., shortly after heading off on a run from Portland to Great and Little Diamond islands. He said the sailboat was between Little Diamond and House islands when the storm came up.

“It got real dark over Portland, so we knew we were going to get hit,” Tracy said.

The small sailboat flipped over in a wind gust, pitching the four people aboard into the water, Tracy said. He stopped his ferry and tried to position it near the people in the water. But, he said, he couldn’t get too close because he was afraid the ferry could hit the people in the water.

“It was blowing so hard I was side-to the wind,” Tracy said. “I couldn’t get (the boat pointed) into the wind.”

Tracy said his crew tossed a life ring to a woman in the water and pulled her aboard. He said a passing Portland Fire Department boat picked up the other three, then followed the Aucocisco to Little Diamond Island, where the woman was put ashore.

Rescue boats are seen in Casco Bay as emergency crews remove people from a capsized boat on Saturday. (Ben McCanna/Staff Photographer)

Tracy said a paramedic on the boat checked out the woman and said she wasn’t injured. He said the fire boat crew told him the other three were fine as well.

“They weren’t in the water too long,” he said.

The fireboat crew picked up the woman from Little Diamond Island and took her into Portland with the three others who had been on the sailboat.

He said that efforts were being made to recover the sailboat, but that it was still upside down in the water by about 6 p.m.

The storm swept through Portland in about 15 minutes late Saturday afternoon. The National Weather Service said winds at the Portland International Jetport gusted up to 40 mph and radar indicated winds of 70 mph near Peaks Island, although that was well above ground level.

Stonemason Barry Shaw takes in the scene of destruction after a swift-moving squall knocked down several trees on Peaks Island, including one that narrowly missed a house at on Brackett Street. A chimney that Shaw built at the home withstood some of the impact without any noticeable damage. (Ben McCanna/Staff Photographer)

By early Saturday evening, about 563 customers of Central Maine Power Co. were without electricity, down from nearly 4,000 at the height of the storm.

A line of heavy thunderstorms passed through York County around 6:30 p.m. A partially fallen tree brought down power lines on Route 103 in Eliot.

Trees were knocked down by thunderstorms in Eliot on Saturday. (Jill Brady/Staff Photographer)

The storms near Portland earlier in the day knocked down trees in Gorham and on Peaks Island, officials said.

CMP indicated that it hoped to have electricity restored to most of those customers who lost power Saturday night.