Icefields Mystery Trails

BoingBoing readers may help me identify what made the trails in the photo below, taken from Icefields Parkway in Banff National Park. I took the photo from the road when I noticed what looked liked ski trails. Except I don't believe they are ski trails; they were in a remote area where it would not be safe to ski.


The above picture is a blow-up from this photo, which might provide more context. I should also add that I'm not a skier nor a snowboarder.