Athabasca River ice jam formation and release events in 2006 and 2007

Abstract

Abstract River ice jams often lead to disastrous floods, since the sudden failure of a major jam is like a small-scale dam break, producing violent ice runs and rapidly rising water levels. Although the resulting flood wave attenuates as it travels downstream, water levels can rebuild again if the ice run is stalled even briefly. Because of the rapid development of high water, it is highly desirable to be able to forecast ice jam events. However, the advancement of knowledge of these events is limited by the lack of reliable field data. Such data is also needed for validation of numerical forecasting models. This paper presents details of the field observations of ice jam events carried out in 2006 and 2007 on the Athabasca River at Fort McMurray, Alberta (AB), Canada. The river breakup in both years was quite dynamic, with extensive ice runs, as well as ice jam formation and release events. Quantitative data describing the speed, height and shape of ice jam release waves and the celerity of breaking and shoving fronts, as well as qualitative data describing the ice conditions, provide unique and valuable data contributing towards a better understanding of the dynamics of ice jam formation and release processes. Through application of numerical ice jam release modeling, wave propagation, ice resistance effects and ice–water interactions are explored using these data.