In steep mountain topography, relying on cellular navigation apps is a leading cause of Search & Rescue dispatches. Battery failure in cold alpine temperatures, screen glare blinding rhodopsin night vision, and delayed cloud routing create critical disorientation. HushHike computes mathematical ephemeris and kinematics before departure, encoding critical safety limits onto physical 3×5 index cards and calm acoustic briefings so you can stow your phone and navigate by natural terrain features.
Published in Waldo Tobler's landmark paper Three Presentations on Geographical Analysis and Modeling, this exponential formulation captures empirical human walking speed on varying terrain slopes. Peak velocity occurs at a gentle downhill (-2.86° or -0.05 slope), while uphill scrambles suffer exponential deceleration.
Standard weather forecasts report astronomical sunset at a flat sea-level horizon. In mountain valleys and cirques, high ridgelines to the west block direct solar illumination 20 to 45 minutes earlier. Once the sun crests the ridge, ambient lumens drop by 99.8% within 12 minutes.
Devised in 1892 by William Naismith and refined in 1984 by Eric Langmuir. For descent on slopes steeper than 12° (21%), Langmuir adds 10 minutes per 300m of elevation loss to account for joint eccentric braking forces.
Developed by the US Army Research Institute of Environmental Medicine (USARIEM), this formula predicts metabolic expenditure M (Watts) as a function of hiker mass W, pack load L, velocity V, slope grade G, and terrain terrain terrain coefficient η.