N.D. Cent. Code § 40-42-05
All municipalities in this state shall be exempt from all liability to any person for damages for injuries suffered or sustained by reason of the accumulation of snow and ice upon the sidewalks within the municipality unless actual knowledge of the defective, unsafe, or dangerous condition of the sidewalk or crosswalk shall have been possessed by the executive officer, governing body, police officer, or marshal of the municipality at least forty-eight hours previous to the damage or injury. Actual knowledge shall not be presumed from the fact of the existence of the condition, but it shall be proved as an independent fact. No municipality in this state shall be liable in damages for any injury occasioned through the mere slippery condition of the sidewalk or crosswalk due to the presence of frost or loose snow thereon.
N.D.C.C. § 40-42-05