2003 GMC Envoy Owner's Manual - Page 275

Here are some things to do to summon help and keep yourself and your passengers safe: Turn on your hazard flashers. Tie a red cloth to your vehicle to alert police that you've been stopped by the snow. Puton extra clothing orwrap a blanket around you. If you have no blankets or extra clothing, make body insulators from newspapers, burlap bags, rags, floor mats - anything you can wrap around yourselfor tuck under your clothing to keep warm. You can run the engine to keep warm, but be careful. 4-42