Hi Jill,

I'm sorry to hear about your trees!  Based on what I can see in the photo, I suspect your trees have been injured by the white pine weevil, and insect that specializes in attacking the tops (and only the tops) of blue spruce trees.  

This fact sheet outlines life history and control methods: https://extension.colostate.edu/topic-areas/insects/white-pine-weevil-5-606/

You can cut the dead tops out of the tree and should be able to train a new leader for the spruce without issue; just diligence over the next few years to make sure that you don't have several trunks develop from this point; that structure could be vulnerable to storm breakage.  Simply prune/shorten all but one of the branches that begin growing upwards to replace the dead top, which will happen naturally.

I hope this is helpful.

Cordially,

John