Updated

Authorities say a boat that capsized in Alaska's Glacier Bay National Park has claimed the lives of a father and son.

Four others on the 21-foot aluminum boat were rescued Monday. They include one person who suffered severe hypothermia and was flown to a hospital in Juneau.

Park official Tom VandenBerg identified the men who died as Larry Roger McWilliams, 75, and Gary Roger McWilliams, 48. He says the elder McWilliams carried an Oregon driver's license, and the younger man was from California. Their hometowns were not immediately available.

The cause of the capsizing was a mystery. The weather was clear and calm in the area where the boat was fishing.

VandenBerg says one person managed to swim to shore and flag down a passing boat.