The most important part of enjoying—and surviving—the Alaskan backcountry is to be prepared. Know where you’re going; get maps, camping information, weather, and trail conditions from a ranger before setting out. Don’t hike alone. Two are better than one, and three are better than two; if one gets hurt, one person can stay with the injured person and one can go for help. Bring more than enough food so hunger won’t cause you to continue when weather conditions say stop. Tell someone where you’re going and when you’ll be back.
Always carry the essentials: a map, a compass, a water bottle, a first-aid kit, a flashlight, matches or a lighter, and fire starter (Vaseline and cotton balls work great), a knife, extra clothing (a full set, in case you fall in a stream), rain gear, extra food, and sunglasses—especially if you’re hiking on snow. Many travelers now also carry along a GPS unit to stay oriented. Cell phones are popular but often don’t work in remote areas. Satellite phones are the ultimate safety toy, but they are a pricey addition to your trip.
Check your ego at the trailhead; stop for the night when the weather gets bad, even if it’s 2 p.m., or head back, and don’t press on when you’re exhausted—tired hikers are sloppy hikers, and even a small injury can be disastrous in the woods.
Anyone who spends much time in the outdoors will discover the dangers of exposure to cold, wet, and windy conditions. Even at temperatures well above freezing, hypothermia—the reduction of the body’s inner core temperature—can prove fatal.
In the early stages, hypothermia causes uncontrollable shivering, followed by a loss of coordination, slurred speech, and then a rapid descent into unconsciousness and death. Always travel prepared for sudden changes in the weather. Wear clothing that insulates well and that holds its heat when wet. Wool and polypro are far better than cotton, and clothes should be worn in layers to provide better heat trapping and a chance to adjust to conditions more easily. Always carry a wool hat, since your head loses more heat than any other part of your body. Bring a waterproof shell to cut the wind. Put on rain gear before it starts raining; head back or set up camp when the weather looks threatening; eat candy bars, keep active, or snuggle with a friend in a down bag to generate warmth.
If someone in your party begins to show signs of hypothermia, don’t take any chances, even if the person denies needing help. Get the victim out of the wind, strip off his clothes, and put him in a dry sleeping bag on an insulating pad. Skin-to-skin contact is the best way to warm a hypothermic person, and that means you’ll also need to strip and climb in the sleeping bag. If you weren’t friends before, this should heat up the relationship! Do not give the victim alcohol or hot drinks, and do not try to warm the person too quickly since it could lead to heart failure. Once the victim has recovered, get medical help as soon as possible. Actually, you’re far better off keeping close tabs on everyone in the group and seeking shelter before exhaustion and hypothermia set in.
Frostbite is a less serious but quite painful problem for the cold-weather hiker; it is caused by direct exposure or by heat loss because of wet socks and boots. Frostbitten areas will look white or gray and feel hard on the surface, softer underneath. The best way to warm the area is with other skin: Put your hand under your arm, your feet on your friend’s belly. Don’t rub it with snow or warm it near a fire. In cases of severe frostbite, in which the skin is white, quite hard, and numb, immerse the frozen area in water warmed to 99–104°F until it’s thawed. Avoid refreezing the frostbitten area. If you’re a long way from medical assistance and the frostbite is extensive, it’s better to keep the area frozen and get out of the woods for help; thawing is very painful, and it would be nearly impossible to walk on a thawed foot.
Although lakes and streams in Alaska  may appear clean, you could be risking a debilitating sickness by drinking the water without treating it first. The protozoan Giardia lamblia is found throughout the state, spread by both humans and animals (including beavers). The disease is curable with drugs, but it’s always best to carry safe drinking water on any trip, or to boil any water taken from creeks or lakes. Bringing water to a full boil for one minute is sufficient to kill Giardia and other harmful organisms. Another option—most folks choose this one—is to use a water filter (available in camping stores). Note, however, that these may not filter out other organisms such as Campylobacter jejuni, bacteria that are just 0.2 microns in size. Chlorine and iodine are not always reliable, taste foul, and can be unhealthy.