This material builds up on snow after repeated applications. It is red in color and used by law enforcement agencies. Several companies sell the product.
Another item used in casting tracks in snow is Potassium sulfate, mixed into the water used for the plaster mix. It lowers the freezing temperature of the water so that it won't freeze in the track before setting up.
Dr. Grover Krantz said that he cast directly into snow with plaster of paris and it worked for him. This was just a dog track though. A sizable track would have a lot more plaster in it and that would cause even more exotherm problems.
Snow casting is difficult... too runny of a mix and it pours through to the ground... too thick and it traps air between the mix and the track surface.
Hope I didn't speak out of turn.
Posted on May 22, 2002, 7:58 PM from IP address 12.230.53.185