Beloved Sierra skier dies after collapsing on climb despite massive rescue effort

Bernard "Bernie" Rosow, a famous backcountry skier and longtime employee of Mammoth Mountain resort, died suddenly from an apparent heart attack Thursday during a skiing trip.

Rosow, 45, collapsed while climbing Bloody Mountain around 9:30 a.m. Thursday, according to a news release from the Mono County Sheriff's Office. He and others with him were heading toward the summit ridge at about 11,400 feet.

Professional photographer Christian Pondella told SFGATE that Rosow sat down abruptly, complaining of sudden back pain and then stopped responding to his friends. SFGATE and the Chronicle are both owned by Hearst but operate independently.

"It happened so quick," Pondella told SFGATE. "Two minutes before that he was having normal conversations."

Rosow's friends texted 911, prompting a massive rescue effort by helicopter and snowmobile, including a "hasty team" made up of a wilderness EMT and a rigging specialist, even as Rosow's friends spent hours performing CPR in an effort to keep him alive.

"Despite the strong and extensive efforts of all involved - especially his group's initial efforts prior to (rescuers') arrival - we are saddened to report that he was ultimately pronounced deceased," the sheriff's office said.

Rosow's death was confirmed in an Instagram post by his partner, Amber Feld, with whom he had a son, Alexander, 8.

"We lost Bernie yesterday," she wrote Friday. "Alexander's favorite person in the world and my love."

Feld said she believed Rosow suffered from a "heart health incident and passed quickly," and recalled that when the two met, Rosow had told her he was planning on hiking Bloody Mountain.

Fifteen years later, it remained one of his favorite places to hike and ski, she said in the post.

"We love him and miss him so much," she said in an email to the Chronicle.

Rosow, a native of southern Vermont, began skiing as a toddler, according to a 2017 profile in the Blackmail online magazine. He moved west in 1999 to pursue a life of skiing and outdoor adventure, first in Utah and then in California a few years later.

When he arrived at Mammoth, Rosow slept in a tent in the woods until he found a job as a snowcat operator, according to March 2025 story in Ski.

"I told everyone I wanted to ski every single day it snowed, I wanted to be the first person in the lift line, and I didn't want to talk to people at work," he told the magazine. "They told me I should be a cat driver."

For 20 years, he skied every powder day, with the exception of the day his son was born, he said in the interview.

Rosow had earlier hoped to be a paid professional skier but told the Blackmail that he'd been unable to afford the travel required to "pursue it seriously." He found that trail grooming gave him a way to ski whenever he wanted.

Rosow routinely worked 70-hour weeks, skiing during the day and grooming runs at night, he told Ski.

He developed a following of more than 100,000 on TikTok, becoming one of Mammoth's best-known skiers.

His TikTok page included a brief bio that described his philosophy:

"Snow cat operator for Mammoth Mountain. Work all night to ski all day."

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This story was originally published April 25, 2026 at 7:18 PM.