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Ice processes in general, and ice jams in particular, play a dominant role in the hydrologic regime of Canadian rivers, often causing extreme floods and affecting the life cycle of many aquatic, terrestrial, and avian species. Various numerical models have been developed to help simulate the formation and consequences of these very dynamic and often destructive jam events. To test and compare the performance of existing models, a series of three tests have been devised and coordinated by a task force appointed by the Committee on River Ice Processes and the Environment (CRIPE). The results indicate that the overall performance of the models is good when calibration data are available, but considerably more varied when the models are applied in uncalibrated or 'blind' mode. However, the diversity of results in the blind mode may be attributed more to the variations in perceptions of the physical processes by the users, as compared to the mechanics of the numerical computations. Key words: Calibration, case study, field data, ice jam, model testing, numerical model, river. Les processus de glaces en general, et les embacles en particulier, ont un role predominant dans le regime hydrologique des rivieres canadiennes, causant souvent des inondations extremes et touchant le cycle de vie de plusieurs especes aquatiques, terrestres et aviaires. Plusieurs modeles numeriques ont ete developpes pour aider a simuler la formation et les consequences de ces evenements d'embacle tres dynamiques et souvent destructeurs. Pour verifier et comparer le rendement des modeles existants, une serie de trois essais a ete concue et coordonnee par un groupe de travail assigne par le CRIPE (Committee on River IceProcesses and the Environment). Les resultats indiquent que le rendement general des modeles est bon lorsque les donnees d' etalonnage sont disponibles, mais varie considerablement lorsque les modeles sont appliques en mode << aveugle >> ou non etalonne. Toutefois, la diversite des resultats en mode << aveugle >> peut etre attribuee plus aux variations dans les perceptions des procedes physiques par les utilisateurs, que par la mecanique des calculs numeriques. Mots-cles : etalonnage, etude de cas, donnees de terrain, embacle, essai de modele, modele numerique, riviere. [Traduit par la Redaction], 1. Introduction Ice processes play a dominant role in the hydrologic regime of Canadian rivers and are intimately related to the life cycle of many aquatic, terrestrial, and avian species. [...]