If the snow is soft/fresh deep ruts form at each gate because that is where all the racers turn. Deep ruts give the racers with low number bibs a huge advantage. If a racer gets in trouble, ruts can act like a ski jump and launch the racer.

Often places will inject a race hill with water and let the water freeze solid. An icy course makes it fairer for all racers. It is also much safer. This is done for all serious races.

Source: I have spent many hours pushing new snow off of race courses. You can do it if there isn't too much snow. These people were overwhelmed with too much snow.