 The Soviets possessed more than three times as many soldiers as the Finns , thirty times as many aircraft , and a hundred times as many tanks . The Red Army , however , had been crippled by Soviet leader Joseph Stalin 's Great Purge of 1937 . With more than 30 @,@ 000 of its officers executed or imprisoned , including most of those of the highest ranks , the Red Army in 1939 had many inexperienced senior and mid @-@ level officers . Because of these factors , and high morale in the Finnish forces , Finland repelled Soviet attacks for several months , much longer than the Soviets expected . 
