Future floods using hydroclimatic simulations and peaks over threshold: An alternative to nonstationary analysis inferred from trend tests

•Inference of nonstationarity from trend tests (INTT) was compared to cause-and-effect processes (INCE) for future floods.•INTT on historical floods may not represent their evolutions into the future.•Trends on flood attributes showed decreasing behavior in selected stations of Alberta.•Using INCE, floods in 2/3 of selected catchments are projected to intensify in the future.