A group of five male snowmobilers were traversing a frozen patch of Seeley Lake, in western Montana, on Friday evening, but only two of them made it across, the Missoula County Sheriff's Office said.
One man was "was saved by a friend in his group that belly-crawled on ice to recover him from the water," the sheriff's office said.
The man, whose identity has not been released, was hypothermic and transferred to a nearby hospital for treatment, officials said.
Two bodies of two other men missing in the lake were spotted by a search helicopter several hours after the accident. "Both have been extracted and have been confirmed deceased," the sheriff's office said in a social media posting.
Their identities were not released.
There are more than 350 miles of groomed snowmobile trails around Seeley Lake, according to local officials.