This story has been updated. Find the newest version here.
A man was missing on the Cook Inlet mudflats Sunday night after getting caught in the fast-moving tide while walking back from Fire Island, the Anchorage Fire Department said.
At 4:26 p.m. a caller told authorities two men had tried to walk to Fire Island and were struggling to make their way back as the tide quickly came in, said AFD battalion chief Mark Hall.
One man made it to shore but the other was seen going under the water, according to Hall.
Witnesses on the beach at Kincaid Park reported seeing the men "walking then starting to swim and then one went under," he said.
The man who made it back to shore was hypothermic and in shock but able to speak, Hall said.
It's not clear how close the men were to shore when the missing man went under. His name is not being released by authorities.
Sunday's tide is one of the most extreme of the year, Hall said.
"It came back a lot faster than they thought," he said.
Witnesses estimated the tide was moving between 10-15 knots and had come up at least 20 feet from the time they first say the men trying to get to shore, Hall said.
Rescuers were searching the inlet and shoreline north of for the missing man from the air and water Sunday night.
The fire department used jet skis to search the area, as well as a dive boat, according to Hall.
LifeMed Alaska helicopters had been called in to help with a grid search, he said. The Alaska Air National Guard was assisting too, a spokeswoman said.
The search area was focused on the Kincaid Park beach and shoreline and inlet areas north, Hall said.
High tide was expected around 8:30 p.m., he said.
Authorities routinely warn about the dangers of the Cook Inlet mudflats, which see extreme tides that can surprise even experienced walkers.
The man missing on the mud flats had completed the trek to and from Fire Island three times, Hall said the man's friend told authorities.
By MICHELLE THERIAULT BOOTS