== 1. Wind chill (Osczevski & Bluestein 2005) == T(C) V(m/s) T_wc(C) frostbite of exposed skin -20 2.5 -26.7 low risk (>30 min) -20 5.0 -30.0 exposed skin freezes in 10-30 min -20 10.0 -33.6 exposed skin freezes in 10-30 min -20 15.0 -35.8 exposed skin freezes in 10-30 min -20 20.0 -37.6 exposed skin freezes in 10-30 min -25 2.5 -32.7 exposed skin freezes in 10-30 min -25 5.0 -36.2 exposed skin freezes in 10-30 min -25 10.0 -40.2 5-10 min -25 15.0 -42.7 5-10 min -25 20.0 -44.6 5-10 min -30 2.5 -38.6 exposed skin freezes in 10-30 min -30 5.0 -42.5 5-10 min -30 10.0 -46.8 5-10 min -30 15.0 -49.6 2-5 min -30 20.0 -51.6 2-5 min Pigol'tsyna (2020, Trudy GGO 597, Table 3) computed for the tent site: -30.3 C at 19 h, -36.5 at 23 h, -45.9 at 03 h, -50.5 at 07 h on 2 Feb 1959 (air -17.9 / -22.5 / -28.7 / -31.7 C, wind 9.2 / 9.4 / 11.3 / 12.4 m/s). == 2. Heat-balance model: anchor check against Tikuisis (1995) published points == (his end point is core 30 C; sedentary; 'nude, 1 km/h' and 'two loose 1-mm layers, 5 km/h') The sketch model is tuned only through sustained shivering (150 W/m2, 6 h endurance) and tissue insulation 0.09 m2K/W. nude, calm, -30 C: model t(30 C) = 1.3 h (Tikuisis: 1.8 h) nude, calm, -20 C: model t(30 C) = 1.9 h (Tikuisis: 2.5 h) nude, calm, -10 C: model t(30 C) = 3.0 h (Tikuisis: 4.1 h) 2 loose layers (taken as 0.9 clo), 5 km/h, -30 C: model t(30 C) = 2.7 h (Tikuisis: 8.6 h) 2 loose layers (taken as 0.9 clo), 5 km/h, -20 C: model t(30 C) = 3.8 h (Tikuisis: 15.4 h) == 3. Dyatlov scenarios: time (h) to core 34 C (incapacitation) / 30 C (unconscious) / 28 C == clothing: 0.5 clo = shirt+trousers+socks (Dyatlov, Kolmogorova, Slobodin-type), 1.0 clo = plus sweater/jacket (Thibeaux, Zolotaryov-type); no boots, hands bare. T(C) V(m/s) clo wet activity | t34 t30 t28 (h) -25 5 0.5 n 0 W | 0.6 1.4 1.7 -25 5 0.5 n 150 W | 0.9 1.9 2.2 -25 5 0.5 y 0 W | 0.4 1.0 1.2 -25 5 0.5 y 150 W | 0.5 1.4 1.6 -25 5 1.0 n 0 W | 0.9 2.0 2.4 -25 5 1.0 y 0 W | 0.5 1.3 1.5 -25 10 0.5 n 0 W | 0.4 1.0 1.3 -25 10 0.5 y 0 W | 0.3 0.8 1.0 -25 10 1.0 n 0 W | 0.6 1.5 1.8 -25 10 1.0 y 0 W | 0.3 0.9 1.2 -25 15 0.5 n 0 W | 0.3 0.9 1.2 -25 15 0.5 n 150 W | 0.4 1.2 1.5 -25 15 0.5 y 0 W | 0.3 0.7 0.9 -25 15 0.5 y 150 W | 0.3 0.8 1.1 -25 15 1.0 n 0 W | 0.6 1.4 1.7 -25 15 1.0 y 0 W | 0.3 0.8 1.1 -25 20 0.5 n 0 W | 0.3 0.9 1.1 -25 20 0.5 y 0 W | 0.3 0.6 0.8 -25 20 1.0 n 0 W | 0.5 1.3 1.6 -25 20 1.0 y 0 W | 0.3 0.8 1.0 -30 5 0.5 n 0 W | 0.5 1.2 1.4 -30 5 0.5 n 150 W | 0.6 1.6 1.8 -30 5 0.5 y 0 W | 0.3 0.8 1.0 -30 5 0.5 y 150 W | 0.3 1.1 1.3 -30 5 1.0 n 0 W | 0.8 1.7 2.0 -30 5 1.0 y 0 W | 0.4 1.0 1.3 -30 10 0.5 n 0 W | 0.3 0.8 1.0 -30 10 0.5 y 0 W | 0.2 0.6 0.8 -30 10 1.0 n 0 W | 0.5 1.2 1.5 -30 10 1.0 y 0 W | 0.3 0.8 1.0 -30 15 0.5 n 0 W | 0.3 0.8 1.0 -30 15 0.5 n 150 W | 0.3 0.9 1.2 -30 15 0.5 y 0 W | 0.2 0.6 0.8 -30 15 0.5 y 150 W | 0.3 0.7 0.9 -30 15 1.0 n 0 W | 0.4 1.1 1.4 -30 15 1.0 y 0 W | 0.3 0.7 0.9 -30 20 0.5 n 0 W | 0.3 0.7 0.9 -30 20 0.5 y 0 W | 0.2 0.6 0.7 -30 20 1.0 n 0 W | 0.4 1.1 1.3 -30 20 1.0 y 0 W | 0.3 0.6 0.8 What the estimate cannot capture: individual variation (body fat, sex, size: Dubinina 20 y, small; Zolotaryov 38 y), exercise-induced heat then exhaustion, wet clothing from snow, paradoxical undressing, frostbite-caused loss of hand function (which ends the ability to build shelter or a fire long before core hypothermia), huddling (the Cedar pair), the snow den's shelter, injuries and shock. Shivering endurance and vasoconstriction are modelled crudely; the model is only good to a factor ~2.