A man who was walking on tidal mud flats with friends in an Alaska estuary got stuck up to his waist in the quicksand-like silt and drowned as the tide came in before frantic rescuers could extract him, authorities said.

Zachary Porter, 20, of Lake Bluff, Illinois, was submerged Sunday evening as the tide came in, and his body was recovered Monday morning, Alaska State Troopers spokesperson Austin McDaniel told The Associated Press. A member of Porter’s group called 911 when they couldn’t get him out, but it was too late, authorities said.

The accident was the latest tragedy at Turnagain Arm, a 48-mile-long estuary carved out long ago by glaciers that travels southeast from the Anchorage area and parallels a major highway.

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At low tide, the estuary is known for its dangerous mud flats made of silt created by glacier-pulverized rocks.

At least three other people have gotten stuck and drowned there over the years. Many more have been rescued, including someone who was fishing there last month.

Read more: USA Today