Glossary D

Articles containing information regarding Glossary D

• Day pack

  A day pack is a small backpack designed to carry the essentials for single-day hikes or side trips away from a main camp. Thru hikers may use one for town walks, side summits, or slackpacking.

• Daylight window

  The daylight window is the practical span of usable daylight available for hiking, breaks, and camp routines on a given day. It varies by season, latitude, terrain, and weather conditions.

• Deadfall

  Deadfall refers to downed trees, large branches, and other woody debris that has fallen to the ground, often across or near the trail. It can slow travel and require careful navigation.

• Declination (magnetic)

  Magnetic declination is the angular difference between true north and magnetic north at a specific location. It affects how a compass bearing relates to map directions.

• Dehydrated meals

  Dehydrated meals are foods that have had most of their water removed to reduce weight and increase shelf life. They are rehydrated on trail with water and sometimes heat.

• Dehydration

  Dehydration is a condition in which the body loses more fluid than it takes in, leading to a net deficit of body water. On long hikes, it can affect comfort, performance, and decision making.

• Desert section

  A desert section is a stretch of trail that passes through arid or semi-arid landscapes with limited shade and often widely spaced water sources. It presents distinct planning considerations.

• Detour

  A detour is a temporary or permanent reroute that diverts a trail from its usual line, often due to closures, hazards, or land management decisions. It may be officially signed or informally adopted.

• Dialing in a kit

  Dialing in a kit refers to the ongoing process of refining gear choices, packing systems, and personal routines to match a hiker’s needs, preferences, and conditions. It is usually iterative rather than a one-time decision.

• Dirt road walk / track walk

  A dirt road walk or track walk is a segment of a route that follows unpaved roads, tracks, or vehicle paths rather than singletrack trail. Many long-distance routes include such segments.

• Double-walled tent

  A double-walled tent is a shelter design that uses an inner body and a separate rainfly or outer layer. The two-layer structure helps manage condensation and weather protection.

• Down fill power

  Down fill power is a standardized measure of how much volume a given mass of down occupies when fluffed under controlled conditions. Higher fill power generally indicates greater loft per unit weight.

• Down insulation

  Down insulation uses the fine plumage beneath the feathers of ducks or geese to trap air and provide warmth in jackets, sleeping bags, and quilts. It is known for high warmth-to-weight performance.

• Drainage basin / watershed

  A drainage basin or watershed is the area of land where all surface water converges to a single outlet, such as a river, lake, or ocean. Trails often cross multiple basins along their length.

• Dream sheet / liner

  A dream sheet or liner is a lightweight fabric insert used inside a sleeping bag or quilt. It can add a small amount of warmth and help keep the primary insulation cleaner.

• Drip line (rainfly)

  The drip line of a rainfly is the outer edge where water naturally runs off and falls to the ground. Its position influences how well a tent or shelter protects against rain and splashback.

• Dry bag

  A dry bag is a waterproof or highly water-resistant bag with a roll-top or similar closure, used to protect gear from rain, splashes, and incidental water exposure.

• Dry camp

  A dry camp is a campsite without an immediate nearby water source, where hikers rely on water carried in from earlier in the day. It is a common planning element in some environments.

• Dry stretch (no water)

  A dry stretch is a segment of trail with no reliable water sources, requiring hikers to carry all necessary water between known points. Such stretches can vary from a few hours to more than a full day of travel.

• Dumping gear (sorting)

  Dumping gear, in a hiking context, refers to fully unpacking and spreading out equipment for sorting, reorganizing, or evaluating what to keep, send home, or replace. It is often done in town or at major transitions.