A cat hole is a small hole, six to eight inches deep, dug to bury human waste in the backcountry where no toilet exists. It is the standard Leave No Trace method for disposing of solid waste, sited at least 200 feet from water, trails, and camp. Toilet paper is packed out or buried depending on the area.
A bear bag is a method of hanging food and scented items in a bag from a tree branch, out of a bear's reach, to protect it overnight. Techniques like the PCT method suspend the bag high and away from the trunk. Bear bags are lighter than canisters but harder to do well, and are banned where canisters are required.
A bear canister is a hard-sided, bear-resistant container that backpackers use to store food, trash, and scented items overnight, keeping them from bears. Required in many wilderness areas, canisters protect both hikers and bears — a bear that gets human food often becomes dangerous and may have to be killed.
A spur trail is a short side trail branching off a main trail, usually leading to a specific feature — a viewpoint, water source, campsite, or summit — and then dead-ending. Hikers take a spur out and back to reach the feature, then return to the main trail to continue.
A blowdown is a tree or large branch that has fallen across a trail, usually from wind, storms, or disease. Blowdowns force hikers to climb over, crawl under, or detour around them, and a trail thick with blowdown after a storm can dramatically slow progress until crews clear it.
Fording is crossing a river or stream on foot where there is no bridge. Hikers face upstream or angle across, unclip the pack hip belt, use trekking poles for stability, and judge depth and current carefully. Swift water is deceptively powerful, making fords one of backpacking's real hazards.
The Yosemite class rating system describes how difficult and exposed terrain is to travel, from Class 1 to Class 5. Class 1 is walking, Class 2-3 is steeper hiking and easy scrambling, Class 4 is exposed scrambling where many use a rope, and Class 5 is technical roped climbing. It helps hikers gauge a route's seriousness.
The alpine zone is the ecological region above treeline, where harsh cold, wind, and short summers allow only low-growing, fragile plants like grasses, sedges, and cushion plants. It offers stunning open terrain but is highly sensitive — hikers stay on rock or trail to avoid trampling vegetation that takes decades to recover.
Treeline (or timberline) is the elevation above which trees can no longer grow, due to cold, wind, and a short growing season. Above treeline the landscape becomes open alpine terrain — more exposed to weather, harder to navigate, and ecologically fragile — so hikers take extra care there.
A ridge is a long, narrow elevated crest of land where two slopes meet, running between or up to summits. Ridge hiking offers expansive views and a natural line of travel, but exposed ridges catch wind and weather and can involve scrambling, making them exhilarating but sometimes serious terrain.