Tanks in Snow 1941-42

Soviet tanks were not without flaws when it came to running in winter conditions. However, discovering these problems early meant that they could be solved early. The Winter War, the USSR's first war where a large number of tanks were used, served as an extra catalyst. Experience in this war gave a lot of food for thought. As a result, the Red Army was better prepared than the Germans for winter warfare. In combination with the cold winter of 1941-42, the complaints about General Winter are not without merit. German industry had to reorient in 1942 to produce winter equipment for its tanks. On this winter day, let us discuss the mobility of tanks in winter conditions, not just Soviet tanks, but those of the Germans and Western Allies as well.

Before the war, the maximum depth of a snow bank that a tank could navigate was not tested. It was more interesting to see how well the tanks dealt with artificial obstacles and slopes. However, this data was sometimes recorded. The T-28 tank could confidently move through 50-60 mm deep snow at a speed of 21-25 kph. The tank could climb a 20 degree slope in snow or 25 degrees if the snow was packed. The tracks began to slip on steeper climbs. However, when driving in deep snow at a temperature of -2-3 degrees the drive sprockets eventually became packed with snow and the tank would stop. This problem was not observed at lower temperatures. The T-26 and BT tanks could drive through 35-50 cm deep snow, a decent depth for vehicles of this class. The BT-7 was at a disadvantage, since the flat track links did not have enough traction to cross certain especially difficult areas.

The T-28 (and T-35) tanks were replaced with the heavy KV-1 in 1939. It had not just thicker armour and more powerful armament, but also a more powerful engine. Full winter trials were not conducted due to the tank's urgent departure to the front. However, the T-34 prototypes were in a different boat. The first trials were conducted at a time when deep snow was readily available. The fact that the T-34 moved through deep snow much better than the BT-7M was noted from the very beginning. The tank managed to drive through snow as deep as 180 cm during its first trials. Tested at the NIBT Proving Grounds also remarked on its high mobility. The tank impressed everyone with its maneuverability. Stalin first referred to the T-34 as a "swallow" back in March of 1940. He repeated that comparison more than once. The production T-34 tank also received grousers which improved its mobility in snow and other difficult terrain.

The new T-50 tank accepted into service on April 16th, 1941, was also supposed to have high mobility in snow. Since there was no snow when it went through trials, this mobility was never measured. The start of the Great Patriotic War mixed up all existing production plans and forced the production of tanks that were not expected, such as the T-60 small tank that was accepted into service on July 20th, 1941, before it was even built. This tank was based on the T-40 reconnaissance tank, which was expected to move through water, not snow. What happened next was an unpleasant surprise.

Some publications claim that the T-60 tank had good mobility in snow since it allegedly did not fall through the crust. Reports from both the GABTU and from the front lines show otherwise. The T-30, T-40, and T-60 tanks showed themselves well on the South-Western Front where the snow was not as deep as elsewhere. They praised the tanks there, especially the T-40. Other fronts reported that the T-60 could navigate 25-50 cm deep snow, depending on how loose it was. If it was tightly packed, 25 cm was the maximum it could traverse.

Even the obsolete T-26 and BT performed better. The T-26 could drive through packed 35 cm deep snow banks. In many cases, the snow was deeper (half a meter), which restricted the use of tanks. There were also a lot fewer T-26 and BT tanks by the winter due to heavy losses. Special spurs were developed on the Leningrad Front where they were more common to help BT tanks navigate deep snow. They can be seen on many tanks that fought in that region. 

All reports on use of tanks in snow agreed on one thing. In many cases, the only tank that could drive through the deep snow was the T-34. Stalin didn't call the T-34 a "swallow flying above the snow" for nothing. This was also the cause for heavy losses of T-34 tanks in the winter of 1941-42. While other tanks were unusable, the T-34 had to go into battle alone and take the most losses, especially since the infantry also fell behind.

What of the KV? In theory, many units that submitted reports on how tanks were used in snow specified that this was the superior tank, but with a caveat: only in well scouted areas. KV-1 tanks stuck in unexpectedly deep snow were not an uncommon sight. The KV-1 lacked the horse power to keep up by the winter due to excessive weight gain. The KV-1 weighed 46 tons at the start of 1941 and gained two extra tons when applique armour was introduced. Putting a cast turret into production led to even more problems. The result was a KV tank that could weigh up to 50 tons or sometimes even more. This is why the KV-1 couldn't drive well in snow and suffered gearbox and suspension damage. Stalin initially ordered development of a more powerful engine, but that turned out to be the wrong solution. The idea of a lightened KV-1 and the KV-13, a heavy tank with the mass of a medium, came out of these experiments.

Unlike Soviet tanks, German ones were not tested in snow. The different climate played a role and the Germans had no reason to conduct these tests. This applied to many nations. The only other country to devote as much attention to driving tanks in snow as the USSR was Sweden. However, trials of a captured Pz.Kpfw.I Ausf.A tank showed that it can drive quite comfortably in snow banks at least 30-40 cm deep. The running gear became packed with snow, but that only led to the tracks falling off once.

The Germans describe the use of their tanks in the winter of 1941-42 laconically. As a rule, there are some complaints about difficulties, but no special reports about mobility were composed. This was because, as Soviet intelligence reports noted, the German tanks largely moved along roads. When a tank column passed through a dirt road in the fall or spring, it turned into an impassable swamp, but in the winter this was often the only way to travel. German tanks had a ground pressure of about 1 kg/cm², which is a lot.

No special trials of German medium tanks for driving through snow banks were conducted but one can make some conclusions. Trials of a Pz.Kpfw.III Ausf.H tank were conducted from January 27th to February 5th, 1942. In these trials, the tank could not climb up a clear 13 degree slope. At the same time, a T-34 tank confidently climbed a snow-swept 15 degree slope.

Winter obstacle trials also gave evidence to the tank's mobility in snow. The T-34 could easily bust through a wall that the Pz.Kpfw.III took 15 minutes to overcome. There were many reasons for this, including a higher power to weight ratio, greater weight, and lower ground pressure. The German tanks moved through snow of about the same depth as the T-26. It's no wonder that the Germans prepared Winterketten tracks for the next winter. The wider track link helped, but not for long. The extensions quickly bent and broke.

The British tanks that first went into battle on the Soviet-German Front in late 1941 also deserve a mention. The Matilda (MK-II in Soviet documents) and Valentine (MK-III) were not built for service in winter. There were many cases where the tanks slipped off the road since the traction with the ground was low. There were also cases where the tanks were immobilized due to the running gear packing with snow. Even these tanks did better in snow than German ones. For instance, the Valentine overcame 60 cm deep loose snow.

Reports from the front line usually lumped the Matilda and Valentine together, but in practice the Valentine was more mobile. Its engine power was often insufficient, but when it came to driving in snow it was a clear leader among foreign tanks.

Even though the Valentine couldn't drive through snow banks as deep as the T-34, it was still better than a T-60. In many cases the Valentine was the only tank of its class that could support infantry divisions in deep snow.