Here is a story that I found on another blog. I think it would make a great object lesson:
The Meaning of the Snowman
The white snow stands for the purity of the souls filled with God's grace. The circular snowballs represent God's everlasting love. The pieces of coal used to make the eyes, mouth and buttons symbolize God's Almighty power. The carrot nose reminds us that God gives us everything we need to live and grow. The scarf suggests the warmth of God's tender care. The top hat reminds us always to keep faith our top priority. The arms are outstretched to us as God's always are. The broom made of straw and wood signifies that Jesus was born and died to cleanse us of sin.
May your heart be ever warmed by the good news of God's great love for you!
You could have fun with this and let the kids make their own snowmen as a craft or you could make a big one as a group.