Well... This is way too complicated. I really like the idea of Avalanche as an auto-growing creature (as opposed to existing growing creatures, that all need skill activation). On the other hand, I really don't get the dividing part. What, an avalanche just keeps getting bigger, it doesn't suddenly turn into 2 distinct avalanches...
My suggestion is to simply remove the "divide" part, and find another way to boost it: maybe +1|+1 each turn ?