Snowmobiles in Yellowstone National Park:
Created by Jen Millner, Geoscience Education Web Development Team, Montana State University
An American right, or wrong?
This module includes information and resources about:
Impacts on Air Quality :: Impacts on Snowpack Chemistry and Water Quality :: Impacts on Wildlife :: Noise Level Impacts :: Economic Impacts :: Public Opinion :: Proposed Solutions and Alternatives :: Particulate Emissions
You will also findTeaching Activities to help teachers and students utilize and integrate the information into the classroom.
Once called "the place where hell bubbles up," interest in the region's astounding geothermal features led to the creation of the world's first national park in 1872. It continues to be most famous for its multitude of geysers, mud pots and hot springs, the total amount of which out number the rest of the world combined. The park also contains the greatest concentration of wildlife in the lower 48 states - mighty moose, great herds of elk, elegant swans, fearsome grizzly bears, elusive gray wolf, and the majestic bison, the only wild bison herd that has survived continuously since prehistoric times and the last free-ranging herd on earth.
What is the controversy all about?Snowmobiling in the park is controversial on several fronts. Conservationists are concerned about how snowmobiles, and snowmobile emissions in particular, may impact wildlife, air and water quality, noise levels, and the pristine aesthetic of the Yellowstone wilderness. Another concern is for the health effects upon both snowmobile riders and park rangers who are exposed to exhaust and high noise levels for significant amounts of time. Supporters of snowmobiling point to other considerations such as the economic benefits to local communities and the importance of preserving access to public lands. They also contend that newer technologies make cleaner, quieter snowmobiles that mitigate the effects of snowmobile use on air, water and noise pollution.
When it comes to conservation versus public access, where do you draw the line?
Snowmobiles were first allowed into the Park in 1963. At the time, the National Park Service (NPS) encouraged sensible snowmobile use in the Park as a way to increase winter visitation. But as snowmobile visitor numbers have grown to more than 75,000 each winter - up to 720 per day - so has concern for the effects that snowmobile emissions, noise, and crowds have on the health of the Greater Yellowstone Ecosystem and those who enjoy it.
Winter use first became a legal issue in 1997 when the animal rights organization Fund For Animals filed a lawsuit to ban all snow grooming of paved roads in the Park, effectively banning snowmobiles because they are only allowed to travel on groomed roads. Upon settlement of that suit, the Park and the NPS began to develop a new usability plan and environment impact statement (EIS) which led to a Record of Decision in 2000 to ban all snowmobiles within the park. This ban became effective in April 2001. A subsequent lawsuit filed by snowmobile manufacturers and supporters prompted a second, supplemental EIS (SEIS) and ultimately overturned that ban in 2003. Legislation continues to be hotly debated while public opinion remains strongly polarized. With both sides still actively pursuing their interests the issue remains unresolved.
Final Rule (more info) - provides background information about the legal events leading up the 2004 decision, a summary of responses to public comments, and economic analyses of proposed alternative management plans.
Yellowstone's Temporary Winter Use Rules
Impacts on Air Quality
One of the biggest concerns about snowmobiling in Yellowstone is whether or not snowmobile emissions cause air pollution. Those opposed to snowmobiles attest that emissions can lead to health problems for park employees who are subjected to prolonged exposure, while snowmobile supporters contend that the toxicity levels of emissions and exposure rates are not significant enough to cause harm.
Most snowmobiles currently in use have two-stroke motors that pass 20-33% of the fuel straight through the engine and out the tailpipe unburned. Standard two-stroke engines also require that lubricating oil be mixed with fuel, so lubricating oil makes up part of the exhaust. This creates most of the visible haze that snowmobiles produce in the form of particulate matter, which itself is composed primarily of volatile organic compounds and hydrocarbons.
Under Yellowstone's Temporary Winter Use Rules, snowmobiles must meet the NPS's Best Available Technology (BAT) standards for noise and exhaust emissions, including carbon monoxide, unburned hydrocarbons and volatile organic compounds, oxides of nitrogen, and particulate matter. These compounds are common mobile source emissions.
See more about carbon monoxide:
- Health and Environmental Impacts of CO
- Environmental Impacts of Newly Regulated Nonroad engines, see page 3.
Oxides of nitrogen (NOx) cause a wide variety of health and environmental impacts because of various compounds and derivatives in the family of nitrogen oxides. It can be an irritant to eyes, nose, throat and lungs. In the environment, it contributes to air pollution, acid rain, and even global warming.
See more about oxides of nitrogen:
The potential health impacts of particulate matter (PM) are two-fold. Most PM is in the "ultrafine" range (less than 100nm) which means that it is respirable and may be deposited in the lungs. Additionally, volatile organic compounds (VOCs) are well-established as possible carcinogens.
See more about particulate matter and volatile organic compounds:
- Basic information about Particulate Matter (PM)
- Health Effects of Particulate Matter (PM) (more info)
- Environmental Impacts of Newly Regulated Nonroad engines, see page 4.
- EPA Factsheet on Toluene
- EPA Factsheet on Benzene
- ATSDR Factsheet on Total Petroleum Hydrocarbons (TPHs)
- ATSDR Factsheet on Polycyclic Aromatic Hydrocarbons (PAHs)
Air Pollution and Health (more info) offers a summary of the above compounds.
What do you think? Compare the information you've just read with the graphs below.
Which type of engine emits the most toxins?
Newer four-stroke engine technology reduces levels of some of these emissions, as well as reducing noise output of the snowmobile. Unfortunately, reducing emission levels does not necessarily reduce the concentrations of those emissions in the air in Yellowstone. The reason is weather. Concentrations may vary depending on wind, temperature, sunlight and inversion.
What do you think?
- How would an inversion effect the dispersion of snowmobile emissions?
- How would this distribution influence health?
- Winter Air Quality Study 2004-2005
- Characterization of Snowmobile Particulate Emissions
- Air Quality Concerns Related to Snowmobile Usage in National Parks
- Scientific Assessment of Yellowstone National Park Winter Use March 2011
- Winter Use Plans/Supplemental Environmental Impact Statement: Air Quality Report
- Spatial Variations and Characteristics of Volatile Organic Compounds Associated with Snowmobile Emissions in Yellowstone National Park
- Air Quality Analysis of Snowmobile and Snowcoach Emissions
- Health and Air Quality Impacts of Bio-based Fuels in Small Engines
Impacts on Snowpack Chemistry and Water Quality
In one study, samples taken from the on-road snowpack near West Yellowstone, the most heavily traveled snowmobile route into the park, contained several varieties of PAHs and VOCs known to be major ingredients in two-stroke engine lubricants. Samples taken in Gallatin Canyon where there is car traffic but no snowmobiles did not contain these compounds.
What do you think?
- According to the first graph, how is the distribution of n-alkanes and n-alkyl acids (an expected oxidation product of n-alkanes) in the snowpack related to proximity to roads used by snowmobiles?
- According to the second graph, how is the concentration of ammonium and sulfates related to proximity to roads used by snowmobiles?
- Based on this research, do you think this distribution can be definitively attributed to snowmobile emissions?
- There are 185 miles of paved roads groomed for snowmobile use in park, most of which are adjacent to rivers, streams and ponds (see snowmobile route map at right). Considering what you have learned about the distribution of pollutants in the snowpack and the effects of toxins on aquatic organisms, do you think there is potential for surface water contamination from snowmelt runoff? Consider factors such as distance of contaminated snowpack from waterbody, contaminant level versus dilution factor (how large is the water body, is it contained or free-flowing?) and so on.
Impacts on Wildlife
Many studies have looked at how wintertime stress affects animal health and survival, but measuring the added stress of vehicle proximity and noise emissions is problematic. Aside from observed interactions between snowmobiles and animals, it is difficult to determine what kinds of long-term impacts snowmobiles may have on animal health from sources such as toxins in snow, water, or soil and the bioaccumulation effects of eating plants that may have taken up these toxins. Furthermore, even highly specialized biochemical studies that look for stress levels in animals may not be able to distinguish the sources of that stress.
Review some of the research:
- Effects of Snowmobiling on Wildlife (page 21) gives an overview of various studies examining the effects of snowmobiles on deer, elk, bison and other wildlife.
- The first page of this report on Wildlife Responses to Motorized Winter Recreation in Yellowstone presents a statistical summary of snowmobile/wildlife interactions and responses.
- Snowmobiles, Wolves and Elk: The Straight Poop discusses the results of studies that examined stress hormone levels in wolf and elk droppings.
- What is the most common reaction animals have to snowmobiles? Do different animals have different reactions?
- Can stress hormone levels measured in fecal matter be definitively attributed to snowmobile activity? What else may cause elevated stress levels during winter?
- Do these studies indicate that snowmobiles are a danger to wildlife?
Human Landscape Issues
Noise Level Impacts
While hearing impairment and high blood pressure are notable health concerns related to sustained high-level noise pollution, when it comes to snowmobiling in the Park the issue is also about how noise emissions affect the visitor experience.
See what those in the snowmobiling industry have to say:
- Leaked Documents Reveal Lies About Snowmobiles in Parks shows evidence for much higher noise levels than technical reports show.(Original document is not available, accessed through archive.org)
- Do noise emissions from snowmobiles have a negative effect on animals?
- Do snowmobile sound levels cause health problems or are they more just a nuisance?
According to a 1998 report on the Economic Importance of the Winter Season to Park County, Wyoming, 30% of local businesses said that nearly 80% of their total winter revenues came from winter visitors to Yellowstone National Park. This table from the report (Acrobat (PDF) 9kB Apr13 06) shows the economic impact to Park Country of YNP visitors. The Wyoming Department of State Parks and Cultural Resources reports that a ban on snowmobiles could cost Wyoming as many as 938 jobs, no small layoff considering the total state population is just under 494,000. Read the article Yellowstone Snowmobile Ban Leaves Working Families in the Cold for more details.
However, there are hundreds of miles of National Forest open to snowmobiles directly outside Yellowstone, so a ban on snowmobiles in the Park would not mean and end to the snowmobile-based economy altogether.
Furthermore, some would argue that the relative economic health of border towns should not be considered a priority when determining how best to preserve the ecosystem health of a national park. As Kevin Collins of the National Parks Conservation Association says, "It is also essential to note that the mission of the National Park System is NOT to provide economic benefits to nearby communities and businesses. Having a national park nearby is an economic asset for which any community would be grateful. Nevertheless, this fortunate byproduct of the park's existence must not be allowed to dictate park management policy."
Some locals believe that a ban on snowmobiles may lead to an increase in snow coach travel and overall visitation due to improved conditions. They are adding snowcoach tours to replace lost snowmobile business. Read more about how Yellowstone Guides and Visitors Praise Snowmobile Phaseout's Positive Impact on Park Conditions.
Visit the West Yellowstone Chamber of Commerce's "White Season" and the Cody, Wyoming Chamber of Commerce's "Outdoor Recreation" to see how the snowmobile industry effects the local economy in these border towns.
What do you think?
- How are small, tourism-dependent towns affected by restrictions on snowmobile use in the Park?
- Are their other options, such as snow coaches or the hundreds of miles of National Forest trails outside the Park, which could mitigate the effects of lost revenue if snowmobiles are banned from the Park?
- Do economic benefits to local communities outweigh conservation concerns?
Pro-snowmobileAccording to the SEIS, more than 90% of winter visitors in Wyoming would not consider taking a snowcoach instead of riding a snowmobile.
- ISMA Yellowstone information sheet outlines the reasons why snowmobiles should not be banned from national parks.
- The Argument to Keep Yellowstone Open: The Truth About Snowmobiling
- National Park's Overestimated Emission & Sound Levels Set Unjust Standard for Snowmobiling in Yellowstone
The original EIS, the SEIS, the Clinton administration, and an overwhelming number of public comments supported banning snowmobiles from Yellowstone.
- Park Tally Opposes Snowmobiles
- Yellowstone Guides, Visitors Praise Snowmobile Phaseout's Positive Impact on Park; With Pollution Reduced, Snowcoach Visitation Climbs
- Snowmobile Damage in Yellowstone and Grand Teton Will Continue
- Judge Criticizes Administration for Halting Yellowstone Snowmobile Phaseout
Proposed Solutions and Alternatives
A snowmobile's impact on the environment and the scenery can be significantly reduced by using ethanol-blended fuels and new engine technologies, particularly four-stroke engines. Studies in Europe have found that biomass-based lube oil can reduce CO, PM, and HC emissions. Find out more:
- Emissions From Snowmobile Engines Using Bio-based Fuels And Lubricants
- Clean snowmobile solutions
- Biomass Alternatives for Snowmobiles
Yellowstone Expeditions provides a brief overview of the mechanics and benefits of snowcoach travel.