1. Make sure you are using the correct wax for the correct weather.
2. Make sure you are doing a good job scraping.
3. Take a gummy stone to the edges and get rid of the burrs.
4. Keep your deck cold. A warm base on cold snow is a sticky situation.
5. Get a new a board. If the slush is slowing you down too much when it gets softer later on it could mean you are riding a wet noodle. Worn in decks don't do well in soft sloush.