Airborne Observations of Three Chinook-Type Situations in Southern Alberta

Abstract

Three chinook situations which occurred in southern Alberta during the winter of 1967?68 were studied using an instrumented aircraft. On the days of observation, local areas experienced warm air penetration toward the surface. On 29 October 1967, severe turbulence and significant warming neat Rolling Hills, Alberta, marked the occurrence. On 18 January 1968, warm air intrusion was found from three large isolated areas of melting snow near Brooks. On 3 February 1968, a shallow layer of cold air covered the southern prairies, with a marked temperature inversion at 50 m above the surface. Local wavelike intrusions of the warm air occurred near Calgary on this day, which was one day previous to the general invasion of warm air from the south. The available data, while somewhat incomplete, were subjected to analysis according to a modified Scorer equation to test for atmospheric and/or topographic inducement of the wave motions observed. Neither method of analysis was completely successful. More detailed and accurate observations of atmospheric motions by aircraft are required.