Oh Now that ive read it here is my assumption
This happens often in other race tracks It usually happens when you make a turn... Why?
The turn is not completly round.. it is made of straight walls that is grouped
together to form a curve... If you hit EXACTLY where the lines meet with one another you can squeeze through the VERY narrow hole..
The reason why it happens often with Blizzard Buoliarvarisnagaroo is because your going too fast... which when you hit the wall is either Sink or Swim..
If you are going fast enough and hit the right spot it you will fall through the wall but if not.. You Hit the wall and continue turning....
This is my Assumption...
Call me if you want me to find out Gliches