All hikers should purchase a good topographical map before embarking on any overnight hike. They are available at stores, visitor centers, and ranger stations throughout Yosemite National Park. Bears live in the high country, so stay alert. In the summer months, mosquitoes are public enemy number one, so bring plenty of repellent. Also pack sunscreen, since much of Yosemite's high country is on granite, above the tree line. Stay off high peaks during thunderstorms, and don't attempt a climb if it looks as though a storm is rolling in. The peaks are magnets for lightning. And finally, trail heads along Tioga Road are accessible only by snowshoes or cross-country skis in winter, as the road is usually closed because of snow from November until June.
Backpacking for Beginners
Backpacking requires more preparation than many other sports, including minute attention to detail. Everything you need for food, clothing, and shelter must be carried with you; the longer the trip, the more planning is needed. It's important to be thorough, and it's also important to be conscientious when it comes to weight. First and foremost, the most important gear is what's on your back and on your feet -- good boots and a sturdy pack are a necessity. You'll also need a good sleeping bag and sleeping pad. Packs generally come in two types: internal and external frames. Opinions vary over which is best; external-frame packs are slightly cheaper, and internal frame packs are better for long distances or trails that twist and turn. Internal-frame packs distribute weight more evenly and cinch tight across your hips, making them more comfortable for long hauls. Try on as many packs as possible. Look for wide shoulder straps, lumbar support, and a wide hip belt. Make sure it feels good and ask lots of questions. If your questions are not answered with painstaking detail so that you feel sure and secure, move on. An uncomfortable or poorly fitting pack is a potential nightmare on a backcountry trip.
Now for the fun stuff -- packing everything you'll need to subsist inside this bag you've bought. One easy method: Pull out everything you could possibly want, and then return most of it from whence it came. You really don't need three pairs of pants or 10 T-shirts.
As for food, a mix of dried foods (pastas, lentils, beans, dried meats, and fruit), crackers, cereal, trail mix (nuts, raisins, and M&Ms), granola bars, envelopes of pre-made soups, and plastic jars of peanut butter and jelly work great. One guy I know hiked the Appalachian Trail with entire loaves of peanut butter and jelly sandwiches, all pre-made and repacked into the bread bag. It worked. And don't forget about water. There is plenty of water in Yosemite's high country, but you'll need to treat it to prevent Giardia. Don't take chances: This little bug is one painful parasite to ingest.
