These are two Soviet New Year postcards from the 1960s. Delivering New Year greetings was a popular theme on New Year postcards, and even snowmen helped out.
Note the Дед Мороз (Ded Moroz) postmark and stamp on the first postcard. Ded Moroz is a fictional character who in some Slavic cultures plays a role similar to that of Santa Claus. The literal translation of the name would be "Old Man Frost", although the name is often translated as "Father Frost" in light of the modern usage of "ded" to refer to a grandfather. Ded Moroz is said to bring presents to children, however, unlike the secretive Santa Claus, the gifts are often delivered "in person", at New Year's Eve parties and other New Year celebrations. (source Wikipedia)
Note also the headgear, which is an upside down pail, unlike the hats worn by American snowmen.
Both postcards are unused, though the second one has a regular postage stamp affixed.
The words "слава труду и науке" on the stamp mean "glory to labor and science."