Large scale atmospheric circulation affecting floods on the Fraser River

A discussion of meteorological conditions existing in the upper air masses prior to and during flood periods of the Fraser River in British Columbia, along with ground observations is presented. Prolonged periods of below freezing temperatures dragging into late spring and then sudden rises in temperature are the main causes of flooding on the Fraser River. Conclusions are drawn to show the need for more detailed research into long term (30 to 90) day weather forecasting, especially temperature changes, for predicting flood stages downstream. Maps, weather charts and tables illustrate the meteorological conditions pertaining to flood periods.