One doesn't typically worry about coming across an unexploded howitzer round when visiting a national park. But it could happen at Yellowstone National Park.

Oh, it doesn't happen very often. The last reported time seems to have been in May 2006 when a construction worker came across a 55-pound artillery shell on Sylvan Pass. Normally those shells, fired from a 105 mm howitzer for avalanche control work on the pass, explode when they pound into the mountains above the pass. This one, however, obviously didn't, and the park had to call in crews from Malmstrom Air Force Base to safely detonate it.

And then there was the time in 1995 a visitor came across another unexploded shell and, not knowing exactly what it was, took it all the way to a visitor center, oblivious to the very real possibility that it could have detonated at any time.

Now, the odds that you might come upon live shells while visiting the Sylvan Pass area of Yellowstone no doubt are miniscule. Very few "duds" are recorded by the park's blasting teams, which are responsible for avalanche control above the pass, and they're aiming at steep mountain chutes, not the type of terrain you're likely to be hiking across. Beyond that, the general area of shelling is off-limits to hikers

But that doesn't mean park officials aren't worried about the possibility of a few, or a few dozen, duds lying around. Last summer they sought contractors to go out and look for unexploded ordnance in the area. The "scope of work" that surrounded this detail was quite open-ended. Under the straight-forward job title of Unexploded Ordnance in Sylvan Pass Avalanche Zone, prospective bidders were told that:

* Park officials really didn't know how large an area needed to be searched;

* The successful bidder would be using "handheld instrumentation to detect below surface UXO (unexploded ordnance)":

* How deep under the ground UXO might be found was an unknown;

* Park officials have no idea how many UXO might be in the area (although, a May 2006 story in the Billings Gazette stated that, "There may be as many as 300 unexploded shells in the hills around Sylvan Pass, according to park rangers.")

What is known is that there are at least 20 identified chutes above the pass that park crews must conduct avalanche control on during the winter months to ensure safe travel for snowmobiles and snowcoaches coming into the park via the east entrance and during the spring to make sure the chutes aren't going to slide while snowplows are working to bust through the snowpack and open the road for summer traffic.

Artillery and The Park Service Mission

It does seem a bit contrary of the misson of the National Park Service to use a piece of artillery that can hit targets roughly 7 miles distant in Yellowstone. That the Park Service does not particularly like bombing within its parks was noted back in November 2008, when it decided that the Burlington Northern Santa Fe Railway could not use howitzers identical to those used in Yellowstone to control avalanche chutes on the southern flanks of Glacier National Park above their tracks.

At the time, Glacier Superintendent Chas Cartwright observed that, “The decision was based on the park’s special status as an internationally recognized natural area, the unique wildlife and other natural resources in the area and NPS values."

“The area of the park that was the subject of this (environmental impact statement) has federally listed threatened and endangered species present, is within the park’s recommended wilderness, provides winter recreation for park visitors and is important winter range for deer, elk and other ungulate species," Superintendent Cartwright continued. "The potential impacts of explosives on threatened and endangered species, wildlife, natural avalanche processes, recommended wilderness and natural sound were determined to be unacceptable.”

Now, Superintendent Cartwright was talking about Glacier. But he just as easily could have been describing Yellowstone and the impacts of bombing the landscape there.

Why the Park Service is able to outlaw the use of howitzers in Glacier and not in Yellowstone is certainly puzzling. In the case of Glacier, the Park Service was not swayed by the railroad's arguments that the interruption of interstate commerce -- upwards of 33,000 container cars a day run on the tracks below the park to and from the Northwest -- was at stake.

In Yellowstone, what's at stake is the entry of fewer than 200 people via over-snow vehicles a winter through the park's east entrance. To safeguard their travel, the park spends about $325,000 a year on the artillery work along Sylvan Pass. During the recently concluded winter season, just 115 snowmobiles, carrying 168 park visitors, passed that way. Put another way, the Park Service spent $1,934.52 per visitor to try to keep Sylvan Pass safe for their passage.

Bombing Some of the Best Wolverine Habitat In Yellowstone

Pushing economic arguments to the side, another question that needs to be discussed is whether the Park Service should be lobbing 55-pound bombs into the best place in Yellowstone "where human-wolverine interactions would be most likely to occur."

Wolverines, the U.S. Fish and Wildlife Service determined back in December, are deserving of Endangered Species Act protection. For now, though, the service is backed up with other candidates worthy of listing, and so the wolverine has been placed on its back-burner. But that doesn't minimize its plight here on Earth.

What is known about the wolverine in Yellowstone is that there are precious few. And that they on occasion pass through the Sylvan Pass area, as evidenced in 2009 when wolverine tracks were spotted on the pass, according to the winter-use EIS.

Canada lynx, already listed as a threatened species under the ESA, also prefer the sort of habitat found around the pass, the EIS noted.

If bombing Glacier's flanks is unacceptable because of the potential impacts on threatened and endangered species, shouldn't the same hold true in Yellowstone?

And park officials realize this isn't the best thing for wolverines, noting in their EIS that "(Over-snow vehicle) use and maintenance (particularly avalanche control methods) may cause wolverines using the area to leave, and/or cause females to abandon their dens for poorer den sites, increasing kit mortality and decreasing the reproductive success of wolverines."

In the end, though, those who prepared the report concluded that avalanche control and snowmobile use over Sylvan Pass would result in "minimal disturbance to wolverines."

Restrictions on movements of lynx or wolverines during the winter months due to the presence and use of OSV routes in other areas of the park may limit the reproductive success, dispersal, and overall genetic sustainability of the species, but such impacts are difficult to predict. Therefore, impacts predicted under this alternative would be long-term minor adverse, with the potential for moderate adverse impacts if lynx and wolverines travel outside the eastern area of the park.

Putting Lives On the Line While Bombing Sylvan Pass

Push resource concerns to the side along with the economic imbalance and the remaining, but certainly not the least, substantive issue revolves around the hazards avalanche control present to those responsible for keeping the pass open. That task is not easy when you consider the 20 avalanche chutes, the need for the Park Service to transport and store 100-300 105mm rounds on-site through the winter, the fact that personnel have to cross eight or more avalanche chutes to reach the howitzer, and the harsh, wintry weather that typically surrounds these efforts.

According to a panel of experts convened in 2007 to discuss avalanche control work in Yellowstone, there is no other place in the National Park System "where NPS rangers are doing this kind of avalanche hazard mitigation or where this type of work is performed for a transportation corridor that is primarily used by over-snow vehicles."

Training personnel to be certified for these skills, and retaining them on staff, are two other issues that arise, according to Yellowstone documents.

Surprisingly, in light of these challenges, since the park started doing avalanche control on the pass in 1973 only one ranger has been killed in the line of duty.

On Monday, January 17th, (1994) Robert Ernst Mahn, Jr., 51, the park's East Area ranger, left the east entrance on a snowmobile patrol west toward Sylvan Pass. About five miles north and west of the entrance, Mahn went off the road and down a 40-to 70-foot embankment. A fellow ranger looking for him about an hour later found him under his snowmobile and summoned assistance.

Responding personnel, including his wife, Grace Nutting, conducted CPR on him during the evacuation and ambulance trip, but were unable to revive him. The accident occurred during a period of low visibility due to high winds and blowing snow, and park investigators believe he may have struck a low-hanging tree branch. Mahn joined the Service in 1973 and worked at National Capital Parks, Canyonlands and Golden Spike before going to Yellowstone in 1976. He'd been the East Area ranger since 1982.

But there also have been "several instances when park employees or visitors had close calls or near misses during avalanche occurrences on the pass," note Yellowstone reports.

Just last week, for example, a wet slide unexpectedly came down on the pass, covering about 70 yards of the road under 20-30 or more feet of snow. While crews were dispatched to reopen the road, before they began plowing they spent a good deal of time probing the snow for any motorists who might have been hit by the slide and buried. They also fired off 18 more rounds from the 105mm gun, just to make sure they wouldn't be hit by another slide while clearing the road.

Not only did avalanches close the east entrance road last week, but heavy snow loads also collapsed the roof of the RV repair facility at Fishing Bridge and caused roof damage to roof of the Grant Village Visitor Education Center.

Politics and Climate Change

So why, in light of the position the Park Service took in Glacier, the costs to a budget-strapped agency, the impacts to resources, and the ever-present danger to rangers and even park visitors, does Yellowstone work so hard to keep the pass open in winter?

The answer isn't surprising: Wyoming politics. Michael Yochim, a park ranger once stationed at Yellowstone and now in Yosemite National Park, wrote an entire book on the snowmobile issue in Yellowstone -- Yellowstone and the Snowmobile, Locking Horns over National Park Use -- and spent more than a little time exploring the political frays that have erupted over this topic. Here's just one snippet:

Fascinated by Yellowstone's weird and unpredictable wonders, stakeholders have long promoted opposing policies for the winter wonderland -- policies that draw upon the conflicting values and identities they treasure, the confounding science on the issue, and their differing political connections. These divergent visions confuse the public and, sometimes, the stakeholders themselves. Caught in the middle is the NPS, an agency that was never strong politically and that lacked its own strong vision of what Yellowstone's winter geography should be like -- two shortcomings that mean the agency is increasingly compromised politically and unable to preserve nature as it desires. Alice would find that the agency charged with protecting the park does not always have the final say in its management; that stakeholders and political representatives often play a game of smoke and mirrors to affect their desired ends; and that science and technology (so revered in America) are more chimeras than definitive aids to policy-making.

What remains to be seen is if this past snowy winter was an anomaly in Yellowstone, or a sign of things to come as a result of the changing climate. Park-wide, the snowpack late last week averaged 126 percent of normal, with various basins ranging from 107 percent of normal to 166 percent.

The current retreat of snow in Yellowstone seems to be about three weeks behind where things were last year, according to park spokesman Al Nash, who said snowplow crews "haven't seen conditions like this in 13-15 years."

If this past winter is indicative of things to come, snowier winters likely mean more avalanche control efforts, and more shelling of Yellowstone's landscape.

Perhaps, in light of the high economic cost with little return, the impacts to resources, the danger personnel are exposed to, and the fact that Yellowstone is a national park, not an artillery range, the preferred alterative for the winter-use plan should be replaced by Yellowstone officials with one that halts snowmobile and snowcoach traffic over Sylvan Pass. After all, that was the position the Park Service took in 2008 before then-Vice President Dick Cheney, a Wyoming resident, intervened.

Public comment on the winter-use plan is being taken through July 13. Let the Park Service know if you support the bombing of Sylvan Pass.