From Cycling PEI

Seems like Cycling Canada is getting serious about Fat Bikes and winter races. Here are some recommended rules for winter and fat bike racing:

Recommended regulations for fatbike & cold weather racing from Cycling Canada

Studded Tires
No screws or other homemade method of studded/spiked tire will be permitted. Studded tires are permitted for use on fatbikes under the following conditions:
− Stud may have a maximum of 3mm prominence from the tire tread
− Must be in the form of a pre-studded factory fatbike tire, or incorporate aftermarket studs designed specifically for bicycle use.
Cold Weather Protocol
If the temperature in a major portion of the course is minus 25° C or below, the competition shall be delayed or cancelled. If the temperature level is between minus 15°and minus 25° C at any point on the course, the event may be canceled or postponed at the discretion of the Technical Delegate and/or Chief Commissaire.