Skip to Main Content

This information is provided free of charge by the Department of Industrial Relations from its web site at These regulations are for the convenience of the user and no representation or warranty is made that the information is current or accurate. See full disclaimer at
Subchapter 7. General Industry Safety Orders
Group 18. Explosives and Pyrotechnics
Article 121. Snow Avalanche Blasting
Return to index
New query

§5357. Snow Avalanche Control Blasting.

(a) General Requirements.

(1) All avalanche blasting shall be conducted under the attended supervision of the blaster in charge who is a licensed avalanche blaster, certified by the Division to perform such blasting activities.

(2) When avalanche blasting is deemed necessary, slopes and trails in the potential avalanche path (runout zone) and ski lifts shall be closed to the public and non-essential personnel and not be opened until the work is completed.

(3) To insure a dry powder train is exposed to the igniter, at least 1 inch of fuse shall be cut from the fuse prior to attaching the igniter. A cutter with sharp blades shall be used to prevent smearing of tar over the powder train.

(4) Charges shall be placed, thrown or propelled to the desired location from a safe position by one of the following methods:

(A) Hand deployed pursuant to subsection (b);

(B) Deployed from a ski lift or tram pursuant to subsection (c) if there is no safe approach to the desired location from the ground;

(C) Deployed from helicopters pursuant to subsection (d) if there is no safe approach to the desired location from the ground;

(D) Deployed from an avalauncher/launcher pursuant to subsection (e);

(E) Deployed from such remote control devices accepted by the Division as providing equivalent safety to the remote control devices allowed under subsection (e).

(5) Avalanche blasting shall be conducted during daylight hours, except during emergency operations.

(6) Avalanche blasting shall not be conducted during conditions where the blaster cannot determine whether the fuse is lit, or clearly identify the location of the target area for the detonation of the charge.

(b) Hand Deployed Charges.

(1) A blaster shall only work with one handcharge at a time.

(2) When placing a handcharge on or in the snow, the crewmember shall be belayed from behind when necessary.

(3) The handcharge shall be lowered by rope, cord or a long pole to the designated location when there is danger that the charge may slide downhill.

(4) Before attaching the igniter, the blaster shall:

(A) Determine the deployment target;

(B) Check the runout zone for personnel;

(C) Check the blast area for personnel;

(5) When the blast area and runout zone are clear, the igniter shall be attached to the safety fuse and immediately activated and the charge deployed within 20 seconds of attaching the igniter onto the fuse.

(6) Avalanche blasting crewmembers shall seek a position of safety behind a pre-selected terrain barrier or a position not less than 100 feet from the ignited charge.

(7) At the completion of individual avalanche control routes, unused charges shall be deployed or disarmed pursuant to Section 5358(h)(1) and all components transported and returned to approved storage magazines pursuant to requirements in Article 121.

Exception: Unused charges that are immediately required for deployment at another location.

(c) Handcharges deployed from ski lifts or trams.

(1) The number of charges thrown from ski lifts or trams shall be kept to a minimum.

(2) The ski lift operating crew shall be informed of the blasting plans.

(3) The ski lift crew shall stand by, in full readiness, for emergency procedures such as the transfer of the ski lift operation to auxiliary power, evacuation, activation of emergency medical system, etc.

(4) The ski lift crew and the blaster in charge shall be in direct radio contact at all times during the blasting operations.

(5) The blasting operations shall comply with requirements of Section 5356(c).

(6) Explosive charges shall be armed prior to entering the lift or tram and shall be adequately protected from impact, vibration, jarring, high temperatures, and electrical currents until deployed.

(7) The avalanche blasting crew shall be traveling up-slope when a charge is thrown.

(8) A charge shall always be thrown down slope and to the side, away from towers, haul ropes, ski lift equipment, moving chairs, cables and other equipment or facilities.

(9) The minimum distance from the blast target to the closest point of the ski lift shall be sixty feet.

(10) Handcharges shall not exceed 4.5 pounds of TNT equivalent.

(11) Fuses shall be of such length that all personnel on the ski lift shall have moved a minimum of three hundred feet from the blast target by the time of detonation, and provide a minimum burning time of 90 seconds from ignition to detonation.

(12) Personnel shall be protected from flying rock and other debris.

(d) Handcharges thrown from a helicopter.

(1) All helicopter operations shall comply with the requirements of Article 35 of the Construction Safety Orders.

(2) Blasting from a helicopter shall be conducted by a licensed avalanche blaster.

(3) The employer shall prepare a written safety plan before each blasting activity shall commence. The safety plan shall include the following:

(A) Procedures to be followed, including provisions for safety in the avalanche runout zone and emergency rescue plans;

(B) Handcharge arming and handling procedures;

(C) The type of explosives to be used;

(D) The qualifications of all personnel involved;

(E) The locations and conditions under which helicopter blasting is to take place.

(4) The employer shall comply with the written safety plan, and shall provide a copy of the safety plan to the Division's Mining and Tunneling Unit before blasting can commence.

(e) Avalauncher/Launcher requirements.

(1) The operation of an avalauncher/launcher shall be under the direct supervision of an authorized, licensed avalanche blaster certified for propelled operation.

(2) Only trained and authorized personnel shall be permitted to operate an avalauncher/launcher.

(3) During loading and firing of explosive rounds, the firing crew shall consist of the blaster in charge, one trained operator, and/or one blaster in training. All other personnel shall be removed to a minimum of 100 feet from the avalauncher/launcher before firing can commence.

(4) All equipment shall be in good working condition, and shall be assembled, maintained, and operated in accordance with the manufacturer's instructions at the launch site.

(5) The components of projectile assemblies shall not be interchanged, and shall be assembled at the launch site and used in accordance with the manufacturer's instructions.

(6) The projectiles shall be inspected before transport to the avalauncher site to ensure proper working condition, and shall be free from damage, obstructions, dirt and debris.

(7) Defective projectiles shall not be used and shall be properly disposed of or returned to the manufacturer.

(8) The projectile's safety devices or components shall not be removed, unless recommended by the manufacturer, and then only immediately prior to inserting the projectile into the barrel.

(9) The operator, and at least one other member of the firing crew shall check the vertical, horizontal (altitude & azimuth), and pressure settings of the avalauncher before each shot is fired.

(10) Operators shall attempt to determine and record whether or not each round which is fired actually explodes on contact.

(11) The approximate location of all known or suspected misfires shall be recorded.

(12) Firing of explosive avalauncher/launcher rounds shall only be conducted when personnel are not in the target area.

(13) The avalauncher/launcher apparatus shall be stored in a nonfunctional condition when not in use, or shall be locked securely to prevent unauthorized use.

Note: Authority cited: Section 142.3, Labor Code. Reference: Section 142.3, Labor Code.


1. Amendment of section and new Notefiled 9-24-97; operative 10-24-97 (Register 97, No. 39).

2. Amendment of subsection (a) and new subsections (a)(1)-(2) filed 7-11-2003; operative 8-10-2003 (Register 2003, No. 28).

3. Repealer and new section heading and section filed 10-10-2007; operative 11- 9-2007 (Register 2007, No. 41).

Go BackGo Back to Article 121 Table of Contents