TheSnowpit.com News Blog

• BNSF denied bombing rights to Glacier NP
• Wasatch gets to shoot, but not Gazex

As the start of the season approaches, ski resorts from Mammoth to Banff are opening their first runs, Gallatin NF and Crested Butte have released their first advisories, and the debates over avalanche control methods begin appearing again in the media.

You may remember my note of the 'shells vs sheds' debate from last season between BNSF Railway and Glacier National Park. After four total years of debating, the National Park service has 'issued a final rejection' to BNSF, telling them to sack up, build some sheds, and stop shooting at the wildlife.

Not all decisions are so logical however. Through a loophole, Alta is allowed to do control work with Howitzers mid-canyon in the Wasatch, but they are not allowed to install Gazex exploders. That is, they are allowed to lob things to within the wilderness areas from without, but they are not allowed to install any actual artillery in the wilderness. Gazex exploders have been used successfully around the world from Europe to Teton Pass.

Alta's Ski Lift solution; A brief history of artillery and avalanche control; Current alternates

With Mount Hood Meadows making a new request for leasing a howitzer and Alta proposing a new ski lift on the south side of Flagstaff Mountain - whilst billing it as a new method of avalanche control via 'skier compaction' - this topic seems a good one for the summer. Enjoy.

A Brief History of Artillery Use in Avalanche Control

This indeed will be brief. After all, I cannot possibly describe the scope and culture of artillery use in avalanche control here. However, a great place to start is Doug Abromeit's paper (PDF) entitled United States Military Artillery For Avalanche Control Program: A Short History In Time. He gives a great overview, complete with some awesome historic photos.

But beyond the history, the idea of shooting down avalanches with large military weapons actually seems somewhat romantic, in the classic sense of the word. It is not only attractively powerful, but it also probably feeds off of the original
myths and tall tales about yodeling and other noises setting off avalanches. Quite interesting, as the concussive force of the shells sets off the avalanches, so perhaps all we need is a really strong yodeler?

Of course, the real attraction to artillery and avalanches seems to be the efficiency: for around $50 a shot and a lease from the military, you can reach all the visible areas of a ski resort - areas that would not be inside of a pedestrian bombing run even with an early morning patrol snowmobile and ski. And you can even reach them when you can't see them in a storm. Hence the prevalence of military artillery used in snow control around the USA, mainly in the form of howitzers, but also some recoilless rifles, and - as Doug's paper mentions - even an armored tank at Stevens Pass. These armaments are used at ski resorts, transportation corridors, and some backcountry venues.

Issues With Artillery

There are many disadvantages of using artillery in avalanche control. They range from area to area. For example, issues currently under investigation from the BNSF / Glacier National Park dispute include concerns such as danger to wildlife as well as who will actually foot the bill for the shells. Whereas, scrutiny for the up and coming artillery plan for Hood Meadows includes concerns for danger to mountaineers!

Specific disadvantages of the howitzer and other military-based artillery include:

• Trained marksmanship is needed to operate the weapons, and with the power behind them, mis-aiming can be extremely hazardous.
• Duds, or fired but unexploded shells, still contain the chemicals to explode and must be carefully tracked and logged to be taken care of later. In addition, mis-manufacturing of the shells can create very dangerous shrapnel and explosive situations for the gunner and attending people while the shell is being fired but is still in the gun.
• And, as the motivation for this overview, all howitzers and recoilless rifles are designated surplus by the US military. That is, both weapons and shells can be hard to come by and may eventually run out.

Which means eventually, no more shells will be available. (At least not at the attractive surplus-type price tag.) And, as the military has stopped producing such weapon types en masse, commercially manufacturing such shells for the lesser demand of avalanche control would be much more expensive.
Of course, one could assume that, as time passes, another weapon currently in military use and fit for avalanche control will be designated as surplus by the military, and folks could use that (whatever that weapon might be) instead. However, there are a few flaws with that theory.

First, it assumes that the weapons released in the future would serve the same purpose as howitzers, that is, the new weapons would actually be useful for avalanche control. And with the prevalence of Stinger missiles and other small, more technological devices in current warfare, howitzers will probably be the last military option for avalanche control.

And secondly, with new, more powerful weapons to hypothetically be had, that new weapon would only solve the lack-of-inexpensive shells issue, not the other issues above. In fact, with greater range and more explosive power, the issues with wildlife, duds, misfires, potential danger to the gunner, confirming the area is clear, and so on would only be exacerbated.

Other Control Plans

Some areas have developed other plans to accomplish avalanche control without artillery, or with reduced artillery. In fact, Doug states in his paper that:

From the beginning, Monty Atwater and other Forest Service Snow Rangers continued perfecting the use of hand delivered explosives and looking for methods to supplement and perhaps replace military artillery.

The alternatives that Doug describes in his paper include:

• Avalauncher or other artillery based on the Parsoneault Valve, and Locat projectile devices
• Gas exploders for snow compression in starting zones (such as the Gaz-Ex Exploder)
• Bomb trams
• Bomb deployment towers (such as the Wyssen Tower)

Of course, as mentioned in Avalanche Mitigation Services' history paper for the Avalauncher (PDF), the compressed gas and Parsoneault valve devices are still not only dealing with explosives, but also highly compressed gas. Plus, some quote the dud rate of the Avalauncher at much higher percentages than howitzers, often higher than 10%. Thus, Avalauncher accidents are not only possible, they've happened in the past, as outlined in in the history paper.

Canada, dealing with the fact that not all areas needing control are accessible by artillery, have long since turned to helicopter deployment as an alternative method of delivering explosives. In addition, even for more accessible areas, the parks turned from artillery early on due to the shell-availability issue. From Brad White's paper entitled Development of Avalanche Safety and Control Programs In the Canadian Rocky Mountain National Parks (PDF Original):

After the Granduc mining disaster in the same year, the technique of helicopter bombing was developed and in the late 1960's Alpine Specialist Peter Fuhrman and local helicopter pilot Jim Davies began to experiment with the helicopter for road control in the Parks. The helicopter proved to be an effective tool and by the end of the decade most of the major avalanche paths effecting roadways were being controlled on a sporadic basis...... In the late 1990's the use of artillery was discontinued due to lack of reliable ammunition and today teams of forecasters based at Sunwapta, Banff and Lake Louise do daily analysis and use a combination of heli-bombing, avalunchers, pre-placed explosives and closures for road control methods in the mountain parks.

In addition, Canada has done some work on short-range projectile delivery, through a multi-target explosive launcher known as ACES positioned at the top and center of the paths. However, according to Brad White's paper, the system has not yet hit the big-time:

In the initial tests the launcher worked very well, but after exposure to the weather the charges froze onto the launcher and eventually the idea was shelved. Work continued on the pre-placed explosive system and a third generation of the Avalanche Control Electronic System (ACES) is still in use today.

The Yellowstone program of 22 years has gone a similar way with helicopters, as stated in their Sylvan Pass Mitigation Plan (PDF):

The program has relied upon military weapons (recoilless rifles or howitzers) since it started. These weapons fire explosive rounds into avalanche starting zones from a gun mount located on the south side of the pass. The artillery enables the crew to test the stability of the snow and attempts to reduce the hazard by triggering frequent small avalanches. This methodology is common among crews who manage highways and ski areas in avalanche prone areas. In 2004 a helicopter was introduced as a method to deploy explosives to avalanche starting zones.

Helicopters reduce the risk of vaulting explosives into someone's backyard, and usually allow for better examination of the area before actually deploying the explosives. Disadvantages of helicopter-based deployment, however, includes the somewhat critical fact that helicopters are limited by weather (Yellowstone allows artillery in case of emergencies). Also, the skill needed for the system is not reduced, just changed - from firing to flying.

Of course the old standbys that don't involve shooting or exploding always exist: sheds, concrete diverters, earthen walls, or simply moving the structure or activity away from hazard, (though of course that's not always an option). After all, as I covered in previous blogs, if BNSF repaired their sheds then shelling wouldn't even be an issue, and if Juneau had built concrete diverters around their powerlines then, well... as I also said earlier, hindsight is always an easier 20-20.

But all in all, it seems that the available options have come a long way since Ed LaChapelle's control and forecasting article from 1960, where he outlines the options for avalanche controls as: Artillery fire, Defense structures, Avalanche signal installation, Weather telemetering, Hazard forecasting, and Research. I wonder what the next 48 years will bring.

• Three survive Hood Avalanche
• The McCain Climate Speech
• Glacier National Park and the Shells vs Sheds Debate
• Federal Land Avalanche Monitoring Bill returns to the Senate
• Heat re-activates Blackcomb's Dec 5 crust

The recent heat has already brought on a few incidents. Blackcomb closed all but two lifts this past weekend due to obvious avalanches and instability. Cornice failures, snow coming loose from rocks, and other natural triggers persist, and a few class-3 avalanches have occured in closed areas in-bounds. Further south, snow came loose from a rock outcropping and sent three climbers for a 350 foot ride on Mount Hood near the Pearly Gates. The climbers survived and descended the mountain with the assistance of Mountain Rescue.

For those of you who, like me, were a little unnerved by the extensive west-wide heat over the last week, perhaps it's time to read McCain's Climate speech, complete with commentary. He poo-poos modeling, brings the issues away from just fossil fuels, proposes increased nuclear power research, and speaks of pressing the issues internationally. An interesting view on how at least one politician views global warming. This was followed up shortly afterwards with commentary on how global warming affects hurricanes and storms. Though not explicitly snow-related, the search for answers for what global warming will do to our planet before it actually occurs continues....

Some classic issues are still present, however. Environmentalists continue to keep tabs on Glacier's plan to use artillery to control avalanches. BNSF Railroad has suffered losses in the past because of avalanches coming off of land located within the park, and wishes to use artillery to control the avalanche risk. Though snow sheds over the rails would be a less-impactful option to the park land in question, the initial investment to construct sheds has BNSF balking and as the rails themselves lie outside of park land, Glacier can only prevent shelling, not require shed building. Started in 2004, the political struggle grinds on.

Sometimes politics aren't all bad, however. Struggling with what could be called the greatest avalanche risk in the country and only one federal avalanche forecast center (Chugach) to help, Alaska's Ted Stevens has re-introduced a bill to require federal avalanche monitoring of federal lands. Though successful in the Senate twice before, the bill has not yet seen success in the House. Maybe a third time will be a charm.