The "storm in progress" rule.

Practice point: A property owner is not liable for accidents resulting from the accumulation of snow and ice on its premises until, after the storm has passed, the owner has had adequate time to ameliorate the hazards caused by the storm.

Case: Marchese v. Skenderi, NY Slip Op 04326 (2d Dept. 2008)

Click here for the uncorrected opinion.