One more time... what movie is this?

I saw it in the 80s or early 90s, and it was about kids who build a giant snow fort for a big snowball fight, but then somebody’s dog dies and everyone is sad. That’s all I really remember, but it’s killing me that I can’t remember the title.

The Dog that Stopped the War?
I actually Googled “movie giant snow fort dog dies” and got a yahoo answers column with that answer.

Thanks much!