Snow mold on grass can comes in two distinct variations, gray snow mold caused by the Typhula pathogen and pink snow mold caused by Microdochium nivale pathogen. These two fungi are incredibly resilient and can survive in teperatures as low as -5 degrees Fahrenheit but is at its most active between 30 and 60 degrees Fahrenheit, depending on variety. The fungi thrives in wet conditions, especially where snow has insulated wet grass for a prolonged period.