Help with movie identification

It may be a show or movie..
But every winter I try to remember a movie I saw either late 80's or early 90's about some kids that have a huge snowball war.
I think there is a dog.
I know there is a big ice fort made.
And I remember a sort of escape hatch from the snow fort where they were sledding out.

Side note: I helped start the caddyshack 2 , Double Jeopardy shenanigans. So don't try and shenanigate a shenanigater.