Three ski patrol members were killed Thursday at Mammoth Mountain ski area when they fell into a geothermal vent that they were working to fence off. Seven other ski patrollers were injured in the incident.
The deaths bring the total this year to eight at the popular Eastern Sierra ski resort, which broke its all-time snowfall record Tuesday. This winter season has been a deadly one for California, with at least 13 skiers dying.
In the wake of a blizzard, four patrollers had been working Thursday morning on the barrier around the natural vent -- a crevasse through which toxic subterranean gases escape -- to keep skiers from the dangerous opening. Mammoth, which rises to 11,053 feet in an active volcanic area, has several such vents, also called fumaroles.
"The gas levels were very high, and when the patrollers first went to fence it off, there was a lot of snow, but the opening was quite small," Mammoth Lakes Mayor Rick Wood said. "There was a 12-foot-wide cave, 22 feet deep. What happened is two of the four patrollers fell through the hole and the snow gave way. Two went in after them, and only one survived."
Members of the ski patrol, firefighters and paramedics responded. The seven injured patrollers -- six of whom responded to the accident -- were taken to Mammoth Hospital in Mammoth Lakes, where most were expected to stay overnight, Wood said.
The names of two of the dead ski patrol members, all men, were being withheld until family members could be notified. The Mono County coroner has not determined whether they died from the fall or from inhaling toxic fumes.
One of the dead was Charles Walter Rosenthal, a researcher for UC Santa Barbara who jumped in to help his two fellow patrollers who had fallen into the vent. University spokesman Paul Desruisseaux said Rosenthal, a married father in his 40s, worked at the Sierra Nevada Aquatic Laboratory in Mammoth Lakes. He was the president of the Eastern Sierra Avalanche Center and an expert in snow hydrology and remote sensing of snow.
Mammoth Mountain officials, skiers and ski patrollers were still trying to absorb the latest tragedy to hit the community about 300 miles north of Los Angeles, a snow sports destination that draws 1 million visitors a year, many from Southern California.
Earlier this year, five people died at Mammoth and a member of the Mammoth ski patrol was killed in an avalanche nearby. In a normal season, three people die in accidents or from natural causes at the resort. Last season, only two people died.
"Whenever you have something like this in a small town, it touches everyone," said Craig Stadtmueller, pastor at Grace Community Church of Mammoth Lakes. "Even though I'm new here, I can't help but be affected by this because everyone I know is affected."
Ski patrol members, who are trained in rescue and first aid, respond to accidents, trigger avalanches to release built-up snow and erect barriers to hazards.
Michael Fanelli, the National Ski Patrol's director at the Northstar ski area in Lake Tahoe, said fatal ski patrol accidents are extremely rare. Before the death of the off-duty Mammoth ski patroller this season, Fanelli said he knew of fatal accidents only in the Rocky Mountains.
"In the last 10 years, I have not heard of any patrollers killed in California," he said.
Jeff "Jake" Smith, 27, who patrolled at Alpine Meadows, was killed in 1982 as he tried to warn skiers to flee a danger zone. An avalanche smothered him and five other skiers. In 1985, a 9,000-foot peak above Lake Tahoe was named Jake's Peak in his honor.
At Mammoth on Thursday morning, the ski patrollers were moving the fencing around the vent near the Christmas Bowl on the upper mountain when the accident occurred at 11:29 a.m. The area where the accident occurred had been closed because of heavy snowfall. As of Wednesday, Mammoth Mountain had recorded 632 inches, or 52 feet of snow since October. The previous record of 617 inches was set in 1992-93.
David P. Hill, the scientist in charge of the U.S. Geological Survey's Long Valley Observatory in the Mammoth area, said the accident occurred at a well-known geologic feature called the Mammoth Mountain fumarole, a vent that releases water vapor and carbon dioxide from deep within the earth. There are a couple of other, smaller fumaroles on the mountain.
The vents, which emit a slight rotten-egg smell, are relatively harmless in summer when the gas dissipates into the atmosphere. "The problem comes in the winter when the snow builds up and covers this thing," Hill said. Hill said the heated gas can melt a cavity below the surface snow.
The area had already been cordoned off so that skiers would not inadvertently cross over it. "They were trying to move the fence further back from the fumerole to protect skiers because they knew it was dangerous," said Hill, who talked to Mammoth Mountain officials. "They were doing the right thing. They were just unlucky."
Mammoth Mountain stands on the southwest rim of the Long Valley Caldera, part of a volcanic chain that extends to Mono Lake. High concentrations of carbon dioxide have been seeping to the surface since a 1989 earthquake and have killed more than 100 acres of trees on Mammoth Mountain.
Volcanic gas emissions are believed to have caused at least two California skiing deaths. In 1998, a 58-year-old cross-country skier from Torrance in good physical condition died in nearby Horseshoe Lake. He was found face down, and he was believed to have died from "carbon dioxide toxicity," according to the Mono County coroner. In 1995, a cross-country skier fell into a fumarole in Lassen Volcanic National Park and survived a week before succumbing to the effects of inhaling toxic fumes.
After blizzard conditions Wednesday, Thursday was a beautiful, clear day on the mountain, with temperatures in the 50s.
Skiers in line to board the gondola to the top first learned that an accident had occurred after a lift attendant suddenly announced, without elaborating, that "the top of the mountain was closed." But within seconds, a skier in line got a call on a cellphone and then told a friend that a ski patroller had died.
Word spread quickly, and the accident was the talk of the slopes, though details were scarce. Skiers saw the emergency vehicles staging at the base of the mountain.
The deaths were another blow to the well-regarded ski patrol, which lost Sara Johanna Carlsson, 31, a native of Sweden, in January when she was killed in an avalanche skiing off-duty near Bridgeport with two other Mammoth ski patrol members.
"When you have folks doing what they are paid to do and falling into a vent, it's close, it's personal and it ripples throughout the community," said Wood, the Mammoth Lakes mayor. "There's a collective feeling of devastation you cannot measure. These are the unheralded heroes who make the mountain work. They're the guys who make it an enjoyable, safe place to ski."
Times staff writers Steve Hymon, J. Michael Kennedy and Hemmy So in Los Angeles and Jeffrey M. Johnson in Mammoth Lakes contributed to this report.