Fill Your Pack
For any alpine excursion, carry a daypack—a lightweight backpack—filled with these essentials:
Trail guide, compass, and map—Learn how to use them before heading out; some outdoor stores offer short courses on using maps and compasses.
Water—"Ideally, you should drink a quart of water per hour, especially at high elevations," says Reid. "This amount of water is pretty heavy, so carry two quarts plus water purification supplies, such as a filter or iodine tablets, then you can refill at streams along the way."
Food—Choose high-energy goodies that will not disintegrate on the trail: energy bars, granola, bagels, pita bread, candy bars, oranges, apples, and raisins.
Extra clothing—Weather in the mountains is very unpredictable. Be ready for anything—cold, heat, wind, rain, or snow.
First aid kit—In a waterproof container, stash some antibiotic ointment, band aids, moleskin, and an ace bandage. Flashlight, waterproof matches—In case sunset sneaks up on you, you will be prepared.
Sunscreen—The thinner air at high elevations offers less protection from the sun's rays, so wear sunscreen year round.
Raingear—Hikers in the west can expect a daily afternoon thundershower in the summer, but all hikers should be prepared.