2018 Polar Bear Plunge! Monday, January 1, 2018 10:00 AM 10:00 PM 10:00 22:00 Google Calendar ICS Join us for the first party of the year on Flathead Lake at the 23rd annual Polar Bear Plunge! All ages welcome to plunge or watch! Chili feed and warm beverages! Plunge at 2 p.m.!