March 9, 2000

Hope Sieck or Jon Catton, Greater Yellowstone Coalition (406) 586-1593
Tony Jewett, National Parks Conservation Association (406) 495-1560

Yellowstone's Visitors Unable to Escape Snowmobile Noise

Sound Survey Monitors 13 Sites

Old Faithful Tops Noise List with Snowmobiles Audible
100 Percent of the Time

Bozeman, Montana — Don´t expect to hear splashing geysers, honking geese or other natural sounds during a wintertime visit to Yellowstone National Park. A recent "percent time audible" study found that the whine and roar of snowmobiles interfered with visitors´ ability to hear natural sounds at 12 out of 13 locations, including the Old Faithful Geyser Basin, Grand Prismatic Spring, and other popular destinations.

At eight of the 13 study sites, snowmobile noise was audible more than 90 percent of the time. "We were thrilled to see a bunch of coyotes near Morning Glory Pool," said Karen Reiter, a Bozeman resident who participated with more than 40 other volunteers in the two-day sound survey over Presidents´ Day Weekend. "But unfortunately the coyotes´ yipping and barking was mixed the entire time with the sound of snowmobiles,"

"The National Park Service is required by law to protect natural quiet and clearly that is not happening in Yellowstone," said Hope Sieck of the Greater Yellowstone Coalition, which organized the sound survey with the National Parks Conservation Association.

In the study, conducted on February 19 and 20, two sets of volunteers on skis and snowshoes traveled to "listening stations" up to two and a half miles from the West Yellowstone-Old Faithful road. For 20 minutes at a time, they identified sounds—natural and unnatural—then repeated the process each hour. The results, compiled in Bozeman, reveal the total percent of time that snowmobiles were audible and interfered with visitors´ ability to hear Yellowstone´s natural sounds. (See enclosed map and table.)

The choice of using "percent time audible" methodology was based on National Park Service policy, which states that "no electronic device can duplicate human hearing for identifying audible sounds produced by non-natural sources." In short, the human ear is the best way to measure whether artificial noise (in this case, snowmobiles) disrupts natural sounds and natural quiet.

At most locations, snowmobiles could be heard more than 90 percent of the time, hour after hour. Volunteers heard the park´s natural sounds with no interference from snowmobiles at only one location out of 13 (Lone Star Geyser).

"The results of this study paint a sad picture of the state of Yellowstone in winter," said Tony Jewett, Northern Rockies Regional Director for the National Parks Conservation Association. "The results clearly demonstrate that visitors cannot enjoy Yellowstone´s magical sounds in many popular locations because the inescapable whine from snowmobiles is drowning them out."

"This study offers compelling proof that the National Park Service needs to find a way for visitors to access and enjoy Yellowstone in winter without damaging the very qualities that people hope to find in their first national park, " said Sieck.

Map of sound survey. 317K image.

Technical Report. The Sound Document