Is it haram to build a snow man?
It is a complicated issue because of the existing Prophetic statements that say statues should not be made. But scholars generally permit children’s toys even if they depict humans. We also know that Aisha, may God be pleased with her, had a toy horse with wings and the Prophet laughed about it without saying anything against it.
The contradictory evidence we have therefore leaves no space for coming up with an answer that completely satisfies. I personally see nothing wrong with snowmen and perhaps we can think of them as similar to toys in that they are a plaything for children.
For more details on these issues please see this page: drawings, paintings and statues in Islam