A pocket-size story that practically turns its own pages and won't quickly wear out its welcome. Berkley (bear) awakes to find snow on the ground, goes out and fools around, then teams up with friend Calvin (ditto) to build a snowman--stage by slow stage across the wide, white-ground double-page opening. But Berkley's ""Hooray for my snowman"" triggers a counterclaim, and in a thrice (""'Nuts to you,' said Berkley"") the two are pelting each other with squishy snow--back and forth, across two wide, white openings. Cold, weary, they go home to recuperate, but when, recovered, they're about to resume the battle, the sight of their demolished snowman stops them. ""So they made a whole bunch of little ones, and went sledding the rest of the afternoon."" Crisply outlined figures, filled in with flat, unhackneyed color, yield a look as simple and inviting as a Crockett Johnson or Eve Rice production.