Yellowstone National Park has updated its proposed winter use plan and issued an associated supplemental impact statement for public review. The preferred alternative calls for the park to manage oversnow vehicles by their overall impacts to air quality, soundscapes, wildlife and visitors rather thanfocusing soely on the number of snowmobiles or snowcoaches allowed in the park each day. Under that plan, the park would allow up to 110 “transportation events’ each day with each event roughly defined as one snowcoach or on the average, a group of seven snowmobiles. The preferred alternative would also provide for one entry per park entrance each day for a non-commercially guided group of up to five snowmobiles. In addition to the preferred alternative, the park announcement says there are three other alternatives up for review. Public comment is being solicited on the alternatives with an open house on July 16th in Jackson and another July 17th in West Yellowstone. Two others will be held July 18th and 19th in Bozeman, Montana and Cody, Wyoming respectively. The alternatives may be reviewed online at the park service website.