Okay here is a video that shows you how we here in Canada make awesome snow forts - in a safe way. Every year we do a big fort. One year it was 25 feet long with an internal slide (see the video for that one!).... and another year we built a slide that went from the deck roof, across the pool and into the entrance (another video made for that one too!). But this video and these instructions show you how we go about doing it (pretty simple really). But always dig with a buddy and use the paint stick trick for added safety.
Step 1: Big 'ol Pile of Snow!
The first step is to pile up a bunch of snow. You want to form your snow hill in the shape you want your future snow fort to be so plan ahead. In this video, we build it off the play structure and over the garden. Make sure the temperature is colder when you do this (definitely not above zero - or 32 Fahrenheit - the colder the better). Let it sit for an hour then you can start digging it out.
Step 2: Start Carving Into It!
This step has you start carving into the snow pile and tunnelling. We used shorter shovels which are more maneuverable in close spaces. Use paint sticks or twigs across the top before you dig to mark the maximum height you can dig up before you weaken the ceiling. This allows you to have a big chamber but you aren't likely to get buried if it should collapse (we've never had a collapse). You dig up from the inside until you see the paint stick then stop.
Step 3: Mark Your Boundaries
You'll want to mark the edge of your snow pile so you don't accidentally dig through. We used hockey sticks and broom sticks to mark our further distance for the tunnel.
Step 4: Enjoy Your Creation!
When you are done, put a light into it and go into it at night... very cool. Have a snow fort party! And just enjoy your creativity!