In the week preceding July 31, a low pressure system sitting over southwestern British Columbia fed warm, humid air into central Alberta. Daytime heating along with near-record dewpoints over Alberta triggered a series of strong thunderstorms that persisted throughout the week. On July 31, a cold front developed over western Alberta, colliding with the warm moist air that persisted over the region. Forecasters recognized the elevated risk for severe weather early in the day. Weatheradio broadcasts and interviews with the media stressed "vicious thunderstorms" and "extremely strong and violent thunderstorms".