GAZEX Exploders in Alpine Valley

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In February Placer County released Draft Findings Report of the sound and vibration study by Bollard Acoustical Consultants. What we’ve learned:

  • The draft study concluded that there was no danger to hearing and structures as measured sound and vibration levels were within OSHA/Caltrans standards.

  • SV/AM has 18 Gazex and 8 are above AMR. They may consider installing more:

    • At Sherwood lift, which is approved but being held up pending resolution of the current issues. The public would be involved in the approval process as this proceeds.

    • At the Saddle Cliffs at Squaw Valley.

    • They have scrapped those planned for the Base to Base Gondola Project.

    • They may consider other sites per ski patrol recommendations.

  • A full ski patrol road mission could potentially comprise 36 shots total versus 8 Gazex discharges to cover the same areas. For the 17 missions this season, if this same work had been done by throwing explosives, would have required approximately 600 hand charges

  • The two night time missions (emergency missions) resulted in 15 slides total. Ski patrol thinks that 4 slides hit the road, but it was hard to tell due to large amount snow fall that was occurring.

  • Over the range tested in the study, Gazex fill time (amount of time propane filled the firing chamber) did not relate to decibel level. In other words, if more gas was used per explosion, it did not result in more noise.

  • The ski patrol feels that the Gazex use has improved patrol safety (eliminated a significant number of patroller missions throwing hand charges), opened the resort sooner, and better protected the community. February 2019 was the snowiest month on record and the patrol would have anticipated some structural damage to homes on AMR, as has happened in less snowy years, but none occurred. They attribute this to the more expedient Gazex triggering of potential avalanches which resulted in smaller slides.

A peer review of the Placer County study was conducted by J.C. Brennan and Associates.

The HOA representatives who are members of the Gazex Advisory Committee are requesting feedback from the community regarding the testing results and possible further actions. The HOA representatives of the Gazex Advisory Committee are meeting on May 15 to discuss any comments from members of the three HOAs, so please send your comments to any of the following Committee members no later than May 14:

Katy Hover-Smoot:
Melissa Siig:
Don Fulda:

HOA representatives want your feedback about the following:

  1. Has pet behavior been altered?

  2. Is there anxiety regarding when the next explosion may occur?

  3. Are windows being damaged (e.g. the window seal)?

  4. Does the safety and utility of the Gazex use out-weigh annoyance and other issues?

  5. Is there an impact on young children?

  6. Could the Gazex be camouflaged?

  7. Would condensing the firing sequence to a shorter period of time be more acceptable? (e.g. Could all Gazex be fired over a 1/2 hour verses an hour timeframe?)

  8. Can the notification system be improved? Are there too many notifications (day before, 2 hour, anytime today, completed Gazex firing)?

  9. Will future Gazex installations go through a more thorough public review?

  10. Other?

Placer County and SV/AM are very willing to consider all of the above and work with us to come to a reasonable resolution on the use of Gazex above AMR. We just need to hear from you! Please email us with your thoughts, additional questions, and any suggestions you might have to mitigate the above potential concerns.


For many years the Alpine Meadows ski area has provided avalanche control along Alpine Meadows Road for Placer County.  This has been done primarily by ski patrol going out on the slope and throwing hand charges to trigger avalanches.

Last year Squaw-Alpine installed eight Gazex devices on the hillside above Alpine Meadows Road.  Gazex devices are large metal tubes supported by a steal frame and a concrete foundation that ignite a propane/oxygen mixture to trigger an avalanche. The advantage of Gazex is that it can be detonated remotely and does not require ski patrol to be out on the slope in hazardous conditions.

Reports from homeowners in Valley who were present when the Gazex devices were used in early 2018 found them to be much louder than the hand charges and the explosive force shook people's homes and windows, and some people's pets were traumatized. For these and other reasons people in the community have expressed great concern.

After hearing the concerns of many homeowners Jennifer Montgomery, Placer County Supervisor for the Tahoe area, helped convene a meeting in October with Squaw-Alpine, County officials, and homeowners.  Over 75 people from the Valley attended, and all expressed concern over the use of the devices and requested they be tested to determine their impact on people, homes, and pets.

As a result of the meeting, the County has retained Bollard Acoustical Consultants, Inc., an independent noise consultant, to assess the impact of the Gazex explosions on people, pets and homes.  An advisory committee has been established by the County to oversee the study, including representatives from each of the three homeowners associations.  Testing of the Gazex devices will occur over the next several months. Squaw-Alpine is also testing different levels of explosive intensity to try and mitigate noise concerns while still providing adequate avalanche control. Squaw-Alpine has indicated they intend to use the devices this winter, but will provide notification via email or text when the exploders are going to be used (see below under Notifications).

Advisory Committee Meeting Minutes:

March 28 2019 Meeting

December 5, 2018 Meeting

Avalanche Control Notification: