Study finds Gazex noise below state, federal levels; Alpine Meadows residents oppose regular usage

Since being installed ahead of the 2017-18 ski season, residents of the Alpine Meadows community have expressed concern and frustration regarding eight Gazex avalanche mitigation system units along Alpine Meadows Road.

Due to complaints from residents about noise and vibrations, fear of potential property damage, and potential health risks such as damaged hearing, Placer County retained Bollard Acoustical Consultants, Inc., a noise and vibration consulting service, to quantify the effects of Gazex use in Alpine Meadows during the 2018-19 season.

Gazex is a fixed location, remote avalanche control system, which explodes a propane/oxygen gas mixture inside an open metal tube. When the system is detonated it creates a pressure wave at the surface of the snow, which is intended to trigger a controlled avalanche.

Bollard Acoustical Consultants studied the eight units from five locations in the Alpine Meadows community. The study took place from Dec. 12, 2018 through Feb. 12, 2019. Ultimately, the evaluation concluded that noise and vibration levels generated by the Gazex avalanche mitigation systems were below state and federal criteria for assessing damage to hearing and structures. A subsequent peer review of the findings was done by j.c. brennan & associates, Inc., and found the analysis accurately measured and analyzed the noise and vibration levels in Alpine Meadows, but did note additional information could have been provided to the community with respect to vibration levels at building facades along with discussions on potential sleep disturbance and potential annoyance.

Placer County polled 129 residents in Alpine Meadows and found that 83.7% said Gazex caused more noise than traditional avalanche mitigation … and 80.4% said there was more vibration …

Placer County polled 129 residents in Alpine Meadows and found that 83.7% said Gazex caused more noise than traditional avalanche mitigation techniques and 80.4% said there was more vibration caused by Gazex.


Several dozen Alpine Meadows residents gathered in Tahoe City Saturday to hear from Bollard Acoustical Consultants, Placer County, and Squaw Valley Alpine Meadows regarding the study and future use of Gazex in the area.

Many voiced concern about noise and vibration, as well as the approval that allowed the installation of Gazex in Alpine Meadows.

Among issues raised were the locations monitoring equipment was set up, accounts of windows vibrating, anxiety caused by the blasts, the notification system ahead of detonating a Gazex unit, and an overall loss of quality of life.

Squaw Valley Alpine Meadows President and COO Ron Cohen addressed the crowd, making the case for continued Gazex use due to ski patroller safety. Cohen said the Gazex system has significantly reduced the amount of hand charges ski patrollers have had to deploy to mitigate avalanche danger along Alpine Meadows Road. Use of hand charges is among the more dangerous activities for patrollers.

“There have been multiple fatalities,” Cohen told the audience. “The latest fatalities due to hand charges were two patrollers in France last January who were killed when their hand charges exploded.”

Cohen added that explosions are rare when it comes to accidents with hand charges, and that when something does go wrong, it more commonly comes in the form of an avalanche coming down from above a patroller.

“It’s a very dangerous situation,” said Cohen. “That’s our goal, to keep our patrollers out of that.”

Residents also argued that the noise created by the blasts exceeds the county’s standards for annoyance, which was shown in Bollard Acoustic Consultants data.

“These levels clearly exceed the county’s standards for annoyance,” said Paul Bollard, president of Bollard Acoustical Consultants, though the measurements were within the state and federal standards for damage to hearing and structures. “There’s no argument there whatsoever.”

The county contended that noise created by Gazex use was exempt under its Public Peace, Safety and Welfare ordinance, which allows for sound sources associated with property maintenance, sounds associated with safety devices, and sounds created due to emergencies.

Cohen argued that homeowners in the community pushed the county to allow them to build in locations that were considered to be in an avalanche hazard area.

“When we had a meeting last year — to everybody’s displeasure — I went through the history of Alpine Meadows and the push and pull, and back and forth between the community and the county, and the community’s desire to build in avalanche hazard areas and the community’s repeated pushing of the county,” said Cohen. “The county tried to put in standards and say you shouldn’t be building in an avalanche hazard area, the community repeatedly came in and said, you are making our property worth nothing, you have to let us build in the avalanche hazard areas. And ultimately, what came out of that was the fair warning system that requires homeowners in Alpine Meadows as homeowners and PAHAs (potential avalanche hazard areas) to prominently post notices in their homes that use of explosives will occur in this area to mitigate avalanche hazards.”


Several residents at the meeting lobbied for Gazex to only be used during emergency situations and asked if manufacturers could make adjustments to reduce noise and vibrations in the area.

Squaw Valley Alpine Meadows, according to Cohen, has continued to push Gazex to make adjustments in the equipment and software to reduce wait time between blasts, and lower sound and vibration outputs. The wait time was associated with anxiety in regard to the frequency of the blasts being problematic.

Another issue many brought up was the county’s approval of Gazex in the first place, stating the project was approved without properly addressing the impacts it would have on those living in Alpine Meadows.

“I make no excuses for what happened prior, but we’re here today,” said Placer County District 5 Supervisor Cindy Gustafson. “And I do commit to you, that we’re going to continue to work on this and modify it, try to work with you on how we notify you, and how often we use it.”

Going into the 2019-20 season, the county and Squaw Valley Alpine Meadows have set up channels of communication, allowing residents to customize how they will be notified of a Gazex blast through email, text and phone calls.

“We continue to address (the Gazex issue) transparently and consistently,” said Cohen. “We’re trying to address it. There’s a balance that has to be struck all the way around. We can’t just abandon the road and the homes along it. We also can’t just ignore the one’s that are also impacted. We have to strike that balance.”

Justin Scacco is a reporter for the Sierra Sun. Contact him at or 530-550-2643.

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