We also have our "IceFest" here. It was on January 28th, 2012.
It was a 4:00 endurance on 4 rounds of 1:00, with approximatively 15-20 minutes break between each round.
We were 12 teams of riders (single man or team of 2-3).
You will certainly think that we ride slowly, but the race rule was very strict: 40 studs/wheel maximum!
Under these conditions, the grip is quite a bit limited...