AbstractA technique is described for stereo photogrammetry of clouds. Movie cameras are set up on a ground baseline 5·6 km long. Time‐lapse films are made with a frame interval of 3 s. The analysis involves the super‐imposition of stereo pair images of the cloud, with advantages over methods previously used.Measurements are presented of an Alberta hailstorm, and estimates are made of horizontal divergence near the cloud tops, and mass flux. Measurements and calculations imply that the ring vortex model of the circulation in small cumulus tops is applicable to some large hail‐bearing storms, and that little or no net mass transfer occurs through the caps of rising cloud