Avalanche Control in Yellowstone Park?


The National Park Service uses artillery shells to mitigate avalanches on Sylvan Pass, which allows access to the park from the east. In the winter, the pass is open only to snowmobiles and


photo courtesy of newwest.net

other “over-the-snow” vehicles. A decade ago, a few thousand snowmobiles might make the trek from Cody to Yellowstone Park over Sylvan Pass. Now the number is closer to a few hundred. Ever since the use of two-stroke snowmobiles was banned in the Park, many of those users are going elsewhere. And yet still the Park clears the slidepaths with explosives.

The annual cost to mitigate the avalanche hazard in the 20 slidepaths on Sylvan Pass, which often gets 350 inches of snow annually, can be as high as $325,000, according to Billings Gazette. Avalanche control teams use a 105 Howitzer, creating  avalanches when the road is closed. Teams have also

Avalanche Paths on Sylvan Pass, photo courtesy of National Park Service

Avalanche Paths on Sylvan Pass, photo courtesy of National Park Service


105 Howitzer used at Alta

dropped explosives from helicopters when the conditions are too dangerous to access the Howitzer.

Sylvan Pass is the only avalanche area within a National Park that utilizes explosives to stay open for tourists. With a high cost and low use, it seems an impractical use of funds.

In 2007, when the Park considered closing the pass in winter, local snowmobilers and politicians were outraged. Conservation groups tried to push back, claiming, among other things, that the risk of unexploded shells tipped the risk/reward calculus into the red. In 1997, a tourist brought an unexploded shell into the visitor center, no doubt starting a massive panic.

According to some estimates, as many as 300 unexploded bombs could be hanging around in the Sylvan Pass area. That number seems both high and astonishing. If there are only half that many unexploded shells, the risk is still high. Some war zones probably aren’t that crowded with duds.

Explosives can fail to detonate for any number of reasons. Once an explosive is lit, it is considered live until it detonates. In military parlance, duds are known as “unexploded ordnance”, and they can pose a risk of detonation even decades after they are lit. A dud, then, is not something to mess around with.


Plows clearing roads in Yellowstone

Recently these duds have been in the news, since the numbers have recently been released. In my opinion, the real issue isn’t the duds, but the need for explosive control at all. Does this road really need to stay open for what seems like an average of one snowmobile a day or less?

Defenders of snowmobiling in Yellowstone continue to fight their battle, hanging onto what Clinton nearly succeeded in ending. But at what cost? Should we continue to keep Sylvan Pass open with federal dollars? Should Yellowstone allow snowmobiling, even the kinder gentler four-stroke engines?

Snowmobiling allows widespread winter access to Yellowstone. And perhaps, that’s a good thing. But with unexploded artillery shells and an explosives budget as high as any Class A ski area, I’m not so sure the cost is worth the effort.

I’d love to hear what you think. Leave your comments below.

4 responses »

  1. I grew up about an hour from the West Yellowstone entrance to the park and have been surrounded by advocates on both sides of the snowmobiling issue for years. I’ve long felt that Yellowstone should be accesible year-round. While closing the park and not plowing/bombing/etc. is both cost-effective and promotes a wilder environment for the native fauna, it limits the ability of citizens to take advantage of this wonderful national resource: the NPS. Plowing some of the main roads and allowing access for and permits to backcountry ski (not just cross-country) would increase winter park usage and potentially bring in many more dollars for funding to the NPS. As to the issue at hand (bombing in the Sylvan Pass area), there are solid pros and cons. It’s expensive and poses a danger to unsuspecting and uneducated individuals. However, closing the area completely would further hinder winter use and decrease park attendance, which would further increase the money available for upkeep of our parks. I feel that if the cost to risk and use ratio is deemed too high an alternative means of opening parts of the park in the winter should be implemented. This could be as easy as plowing 20 miles of road from the West Yellowstone entrance or further in from the Gardiner entrance. While the point of out national parks is to preserve flawless wilderness for the natural fauna in these areas, preventing use of these areas completely will only continue to further decrease funding to these programs and, over time, could lead to the loss of these protected areas completely.

    • Stephanie,

      Thanks for your thoughtful comment. I live near the entrance to Mt. Rainier National Park. Winter access on our side of the park is limited only to those that walk or ski in. Snowmobiles have never been allowed. The Paradise side remains open in the winter, but little avalanche control is required to access that entrance. Perhaps that’s the biggest issue–the use and cost of explosives. I’m an avalanche blaster myself, so I know how extensive a job it is. On the one hand, I’d love to have the job of forecasting and blasting in Yellowstone. On the other hand, as a tax payer, I wonder about the cost. As you say, perhaps there is another entrance that could better serve the needs of winter access. Either way, I agree that winter access to Yellowstone should remain open, one way or another.

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