World War, such as in the fighting in the Dolomite Mountains between Austria-Hungary and Italy. Snow camouflage was used far more widely in the Second World War by the Wehrmacht, the Finnish Army, the Soviet Army and others. Since then, snow variants of disruptively patterned camouflage for uniforms have been introduced, sometimes with digital patterns. For example, the Bundeswehr has a Schneetarn (snow) variant of its widely used Flecktarn pattern. Soviet Army doctrine emphasized the importance of camouflage over positions and the need to remove telltale signs of artillery actions, such as smoke stains or shell casings. It also cited the usefulness of decoy targets. It describes the establishment of breastworks made from snow thick, ice thick or soil and wood thick. Materiel Snow, ice and cold temperatures affect munitions and military vehicles. Munitions – Snow, ice, frozen ground, and low temperatures affect mine-laying operations. Burying mines in a frost layer may be difficult, requiring mines to be placed on top of the ground and then camouflaged. Snow or ice may prevent detonation, owing to freezing the firing device or isolating from pressure above. This can be mitigated with plastic laid over the top of the mine. Vehicles – Adaptations of military vehicles to winter operations include tire chains for maintaining traction of wheeled vehicles. Diesel engines start less well in cold and may require pre-heating or idling during cold periods. A variety of military vehicles have been developed for over-snow travel, including the Sisu Nasu, BvS 10, and M29 Weasel. Military engineering Military engineers design and construct transportation and troop-support facilities. In cold climates frozen ground can make digging difficult. Soviet Army doctrine gave them the responsibility to establish build and maintain routes, including water crossings, build and destroy obstacles that require special equipment, construct and maintain airfields, and to build shelter for personnel. Operations that didn't require special equipment were left to other troops. The Taschenbuch describes a variety of ways to employ local resources to create roads, shelters and fortifications. Engineers provide roadways, landing zones, shelter, water supply and wastewater disposal, and electrical power to encampments. Roadway and landing zones require heavy equipment, which is more fatiguing to operate in the cold and necessary to protect from freezing. Snowstorms require cleanup and spring thaw requires management of thawed soil. Landing zones require stabilization of dust and snow to avoid blinding helicopter pilots. The US Army has cold-weather