Illegal snowmobile use disturbs wildlife, including lynx and wolverine. Grizzly bear tracks are seen year-round up the North Fork, but they regularly come out of their dens in April, long before the snow melts.
Please take some time to familiarize yourself with the USFS map for over snow use (http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5410980.pdf)
and then educate your neighbors and friends. This map is free at USFS offices.
If you observe illegal use, send the Flathead Forest law enforcement agent, Brad Treat, a note at email@example.com.