A WAG bag ('Waste Alleviation and Gelling' bag) is a portable human-waste kit — a double bag with gelling powder that solidifies and neutralizes waste — used to pack out solid human waste where burying it in a cat-hole is prohibited or impractical, such as alpine zones, deserts, river corridors, and popular climbing areas. It's a key Leave No Trace tool for protecting fragile environments and water.
Giardia (Giardia lamblia) is a microscopic parasite found in many backcountry water sources that causes giardiasis, an intestinal illness with diarrhea, gas, cramps, and nausea appearing one to three weeks after infection. It's a leading reason to treat all wild water, and is prevented by filtering, boiling, or chemically treating water and by good hand hygiene.
Sun protection is guarding your skin and eyes from ultraviolet (UV) radiation using sunscreen (rated by SPF), sun-protective clothing (rated by UPF), a hat, lip balm, and UV-blocking sunglasses. It's one of the Ten Essentials because UV exposure intensifies at altitude and reflects off snow and water, causing sunburn, snow blindness, and long-term skin damage.
A blister is a fluid-filled pocket that forms when repeated friction, often worsened by moisture and heat, separates layers of skin — the most common hiking injury. It's preceded by a 'hot spot,' a warm, reddened, tender patch; treating that hot spot immediately with tape or a patch usually prevents the blister from forming.
Snow blindness (photokeratitis) is a painful, temporary sunburn of the cornea caused by intense ultraviolet light, especially UV reflected off snow, ice, or water at altitude. Symptoms — gritty, watering, painful eyes and blurred vision — appear hours after exposure. It's prevented entirely by wearing UV-blocking sunglasses or glacier glasses with side protection.
Hyponatremia is a dangerously low concentration of sodium in the blood, which in endurance athletes often results from drinking large amounts of plain water without replacing salt lost in sweat. Symptoms — nausea, headache, confusion, and swelling — overlap with dehydration but the treatment is opposite, making it a serious and easily misread condition on long efforts.
Dehydration is a harmful deficit of body fluids that occurs when you lose more water (through sweat, breathing, and urine) than you take in. On the trail it causes thirst, dark urine, headache, fatigue, and dizziness, reduces performance, and raises the risk of heat illness. Prevention is steady drinking and replacing electrolytes on long, hot, or high-output days.
Heat stroke is a life-threatening emergency in which the body's temperature regulation fails, driving core temperature dangerously high (often above 104°F/40°C) with altered mental status — confusion, slurred speech, seizures, or unconsciousness. It requires immediate aggressive cooling and emergency evacuation, as it can cause organ damage or death within minutes.
Heat exhaustion is a moderate heat illness from overheating and fluid and salt loss, marked by heavy sweating, weakness, dizziness, nausea, headache, and cool, clammy skin while mental status stays largely normal. It's a warning sign that can progress to life-threatening heat stroke, so prompt rest, shade, hydration, and cooling are essential.
Hyperthermia is an abnormally elevated body temperature caused by the body absorbing or producing more heat than it can shed, the opposite of hypothermia. It spans a spectrum of heat illness from heat cramps and heat exhaustion to life-threatening heat stroke, and is prevented by hydration, pacing, shade, and cooling in hot conditions.