Although prolonged warfare in subzero temperatures and/or at high altitude had occurred from time to time before 1900, the twentieth century saw an unprecedented emphasis on fighting in all terrains, seasons and weather conditions. Such conditions made even basic survival difficult as subzero temperatures caused weapons to jam, engines to seize up and soldiers to suffer frostbite, snow blindness and hypothermia; even the hardiest, best-equipped troops found defending their positions very difficult, let alone conducting offensive operations. The conditions often favoured small groups of mobile, lightly armed soldiers, rather than the armoured forces or air power that dominated other combat environments.
Some European armies developed small numbers of specialist alpine troops before and during World War I, but these proved to be insufficient as nearly all the major combatants of World War II found themselves fighting for extended periods in extremely hostile cold-weather and/or
