<Li> <P> Finnish ski troops during the invasion of Finland by the Soviet Union </P> </Li> <P> Finnish ski troops during the invasion of Finland by the Soviet Union </P> <Li> <P> Army vehicles coping with snow during the Battle of the Bulge of World War II . </P> </Li> <P> Army vehicles coping with snow during the Battle of the Bulge of World War II . </P>

What is the temperature of snow in celsius