A pistol would be hilariously inadequate. As for "detonating explosives", what do you think they are doing? They are shooting high-explosive artillery rounds fr

A pistol would be hilariously inadequate. As for "detonating explosives", what do you think they are doing? They are shooting high-explosive artillery rounds from a tank that detonate on impact. As for "why artillery", how do you plan on getting explosives into the snowpack, especially under conditions of severe avalanche risk? Those areas of the mountains are inaccessible by vehicle even in the summertime. A tank can drive on a road and deliver the explosives where needed. They often target 20+ separate snowfields so being able to do it in a timely and efficient manner matters. While the armor doesn't contribute much, it happens to be what the artillery gun is attached to. It would cost far more to rig some special-purpose vehicle. Sherman tanks are free, the government has loads of them lying around waiting to be scrapped, you just pay for fuel and upkeep.