frozen ground crunching snow heart rate aid station trail marker long run core strength mental toughness finish line winter miles frozen trails frost snow ice sleet chill cold frozen slush mud thaw flurry blizzard drizzle mist fog wind breath steam exhale shiver crunch grip traction darkness dawn dusk twilight overcast cloud trailhead switchback ascent descent summit ridge valley forest woodland moor fell hill mountain peak slope path singletrack bog puddle stream creek river crossing bridge rock root stump branch pine oak leafless barren frostbitten snowdrift avalanche cornice whiteout icy slippery numb tingle breathless endurance stamina resilience determination solitude silence footfall pulse rhythm pace cadence stride elevation altitude effort exertion sweat frostbite hypothermia hydration energy bonk refuel checkpoint map compass GPS route cairn signpost navigation orientation training tempo intervals recovery stretch warm-up cooldown cross-train mobility flexibility perseverance grit adventure challenge freedom nature wilderness landscape terrain escape sunrise sunset stars moonlight visibility safety teamwork camaraderie competition ultra marathon race event medal timing volunteers cheering motivation reward accomplishment satisfaction memory journey experience