If you're missing and we find your car, we will get inside to read your note. Take the correct map and a compass. Know how to use them. Take appropriate clothing and footwear. In the Colorado mountains it is especially important to avoid hypothermia.
Weather changes rapidly in all seasons.
Always take a waterproof windbreaker, and clothing that can keep you warm when wet, e.g. wool. Avoid cotton which absorbs perspiration and rain and becomes cold when wet. Avoid cotton jeans. Even in warm weather in the mountains, be prepared for rains and night cold if stranded. Large plastic trash bags can substitute for raingear in an emergency.