Peaks over threshold flood events in seventy years of data from 202 reference hydrometric stations from cold regions in Canada and the United States were separated into nival, mixed, and pluvial flood types using clustering on the unit circle, climatology, and median daily flows. These groups were then tested for trends over time, with climate indices, with mean annual temperature and with mean annual precipitation. Mann-Kendall trend tests showed few significant trends in flood magnitude. However, using logistic regression, significant changes in flood type fraction were found over time, with annual mean temperature, and with annual precipitation. Nival events decreased in frequency over the seventy-year period in 16% of sites, while mixed and pluvial events increased at 5% and 12% of sites, respectively. These changes indicate a shift from nival events towards more pluvial dominated systems. Fewer significant changes in flood type fraction were found with analysis against four climate indices. Flood frequency analysis using a combined distribution approach with the three flood types resulted in larger magnitude design flow estimates (median increase of 20 – 30 %) in comparison with the results from considering the data to be from a single population.
