Unlock this article and unwrap savings this holiday season. Already have an Outside Account? Sign in Now 30% Off. $4.99/month $3.49/month* Get the one subscription to fuel all your adventures. Map your next adventure with our premium GPS apps: Gaia GPS Premium and Trailforks Pro. Read unlimited digital content from 15+ brands, including Outside Magazine, Triathlete, Ski, Trail Runner, and VeloNews. Watch 600+ hours of endurance challenges, cycling and skiing action, and travel documentaries. Learn from the pros with expert-led online courses. Join Outside+ *Outside memberships are billed annually. You may cancel your membership at anytime, but no refunds will be issued for payments already made. Upon cancellation, you will have access to your membership through the end of your paid year. More Details Backpacker Videos Video loading... Survival Videos WATCH: Rockslide in Grand Teton National Park Share this Facebook Icon Twitter Icon Email Icon Join Backpacker Create a personalized feed and bookmark your favorites. Join for free Already have an account? Sign In Join Backpacker Create a personalized feed and bookmark your favorites. Join for free Already have an account? Sign In David Williamson captured this video of a rockslide while hiking up the Middle Teton in 2013. His friend, Phil White, became trapped by boulders as he was pummeled with debris. Read more about the accident and hear Phil’s account here.