Subzero sleeping bag, water, shovel, sand or kitty litter, protein bars, emergency flares, blanket, matches, flashlights, extra large coffee can (guess what that is for), extra gloves, socks, and packaged "hand-warmers", wind-up radio with weather band and cell charging port... Plus the usual car stuff (battery jump cables and self-contained charger, tire inflator, etc). If I plan to drive long-distance, I add boots and snowshoes, just in case.

Ya never know. I've been on I-25 and I-70 when it has closed, stuck on the side of the road for nearly 24 hours. Sorry for these folks. Hopefully, they will now be motivated to stock their cars with their own emergency kits.