by L. W. Pogue, E. Warner, H. Branch for the Civil Aeronautics Board

“ As the center of the thunderstorm passed to the north of Bismarck, the squall winds accompanying the thunderstorm combined with the northeasterly gradient flow caused a sudden increase in velocity with the wind shifting to northeasterly and becoming relatively strong and gusty. ”

“ The surface winds which had been north-northwesterly from 4:30 p.m. to 6:01 p.m. shifted to north-northeastward at 6:10 p.m. increasing rapidly in velocity with a recorded but unfiled observation indicating north-northeast 21 at 6:18 p.m., but a regular observation at 6:30 p.m. ”