Paula: Obstructed means your behind a life boat and will get light but no view. Wedding wear is o.k.. Snorkeling in Alaska without a insulated wet suit would not be advised as the hypothermia will be quick and you will not be telling stories when you come back. Lows in 30's can be expected at nights and near glaciers. Highs in 60's but with wind chill will feel like 40's. Dress warm.