Using axe to test ice thickness at mouth of Hay Slough Photo Credits: Chas Jones Charlie Campbell carries an axe for testing ice thickness and safety as he approaches an area of overflow and questionable ice at the mouth of Hay Slough. Process Observed: OverflowOpen Water (Refrozen)Ice ThicknessIce Strength Date Process Observed: Tuesday, March 16, 2010 Galleries: Mouth of Hay Slough Gallery