Snowboarder Runs Into Snowcat

We live in one of the most beautiful locales in the world and are blessed with world-class snow skiing and boarding. Not this week, however, as we are inundated with smoke from the destructive fires in Northern California. Our new paradigm.


Kathleen Willhide-Michiulis was boarding at Mammoth Mountain Ski Area on her last run of the day (why is it always the last run?) when she collided with a snowcat pulling a snow-grooming tiller. She got tangled up in the tiller. The accident resulted in the amputation of her left leg, several skull fractures and facial lacerations among other serious injuries.

Willhide-Michiulis, a Mammoth season-pass holder, had signed Mammoth’s release when she applied for her season-pass. The release covered Mammoth’s negligence and collisions with snowmaking equipment and other over-snow vehicles.

Willhide-Michiulis saw the snowcat about 150 feet ahead of her in the middle of the run. As she initiated a “carve” she claimed the snowcat turned and “cutoff her path” and she could not avoid a collision. The snowcat is a large over-the snow vehicle – 30 feet long and 18 feet wide, with a 20-foot wide trailer containing a snow-grooming tiller. Mammoth had between 27” and 44” of snow the night before.


Willhide-Michiulis sued Mammoth claiming the snowcat should not have been in the middle of the run and the operator had not used a left-turn signal, although the snowcat’s warning beacon lights and audible alarm were activated. Willhide-Michiulis sued Mammoth for breach of contract, gross negligence, negligence and loss of consortium. Her attorneys tried to move the case to Los Angeles County, but the trial court allowed the case to stay in Mono County.

Based on the pleadings, the trial court ruled for Mammoth determining Willhide-Michiulis had “assumed the risk of injuries inherent in snowboarding” and had signed the release. She appealed to the Third District Court of Appeal.


The Court of Appeal ruled the trial court had properly excluded the Declarations of Willhide-Michiulis’ experts who had opined that operating the snowcat on an open run with its tiller running was “extremely dangerous” and “an extreme departure from an ordinary standard of conduct” which “violated the industry standard.”

The Court of Appeal focused on the language of the season-pass agreement and release which included a paragraph describing boarding as involving numerous risks, including collisions with “snow making equipment, snowmobiles and other over-snow vehicles.”

The Court reviewed dozens of assumption of the risk sports injury cases.

In particular the Court cited Connelly v. Mammoth Mountain Ski Area where a skier unsuccessfully sued after colliding with an unpadded ski lift tower; towers being deemed an inherent risk of the sport.

The Court of Appeal cited the trial court finding that “the very existence of a large metal plainly-visible [snowcat] serves as its own warning.”


In the end the Court of Appeal, in an opinion written by Justice Robie, one of the best, determined that Mammoth was not grossly negligent. He wrote: “We conclude that the use of snowcats and their tillers on ski runs during business hours is inherent to the sport of snowboarding, the use of which does not unreasonably increase the risks associated with the sport. To find Mammoth liable because it operated a snowcat and tiller during business hours would inhibit the vigorous participation in this sport.”

As Mammoth was not grossly negligent, nor had it increased the risks inherent in boarding, the waiver of liability in the season-pass agreement was effective. Summary judgment ruling for Mammoth.

Mammoth was represented by John Fagan and Kristin Bohm, local lawyers of the Duane Morris law firm.


Jim Porter is an attorney with Porter Simon licensed in California and Nevada, with offices in Truckee and Tahoe City, California, and Reno, Nevada.  Jim’s practice areas include:  real estate, development, construction, business, HOA’s, contracts, personal injury, accidents, mediation and other transactional matters.  He may be reached at or  

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