RE: Making a Blizzard, with a Vortex
I think its sinking in to the snow and rolling over due to the snow being so soft and light - I believe it would do much better on some hardpack snow or even windblown crust.
It looks like the rudder works reasonably well. I have both single and dual rudder set ups and find there is very little difference if you have them scaled correctly and actually prefer single due to ease of set up and less frontal area (minimal).