I would also say that an ice block extending from inside the pool to the inside of the skimmer is probably to blame. To prevent this from happening we drain the water below the skimmer and completely cover the skimmer opening with duct tape, so that no water or ice can get into the skimmer. Then we put a styrofoam peice in the throat of the skimmer. We leave the plug out of the bottom of the skimmer and leave the hose from the skimmer unattached and open at the other end. This way, if water gets into the skimmer it will flow out the end of the hose, not allowing anything to freeze in the skimmer.

Many insurance companies in my neck of the woods still insure AG pools, some don't. I always recommend calling around to find one that does.

Brad
Waterworks Pools