Episode Title:Journey to the Subnivean Zone.Episode Description:When a mission to discover the birth of a snowflake goes awry, the Kratt Brothers discover a strange and unlikely colony of snow creatures living in the mysterious Subnivean Zone. But when Aviva's quest for an engineered "beach vacation" inadvertently alters the fragile northern landscape, the gang must work together to restore the life-giving blanket of snow that is so critical to creature survival.