Quantifying Changes in Extreme Snow Accumulation Under a Future Climate

One key consideration in building design is ensuring that the roof of the building is strong enough to withstand the weight of accumulated snow. The design calculations require probabilistic estimates of annual extreme snow water equivalent (SWE), which are then used to determine how strong to design the structure. This talk explores ongoing efforts to predict how ground SWE, or snow load, requirements will change in a future climate. While shorter snow seasons may reduce extreme loads resulting from long-term accumulations, increased single-storm severity may increase extreme loads in regions subject to ephemeral snow. These possibilities are explored using the estimates of annual maximum SWE derived from the experiments performed by the variable infiltration capacity (VIC) model forced with downscaled global climate model (GCM) outputs at a 6-km spatial resolution via localized climate analogs (LOCA1). These annual maximum SWE values are then used to estimate non-stationary generalized extreme value (GEV) distributions, which illustrate the implications of using non-stationary SWE distributions in a structural reliability analysis. The results show that design snow loads are expected to fall across most of the country as compared to historical estimates, with notable exceptions in the Upper Midwest. Most importantly, the results provide a framework for how engineers can use non-stationary estimates of SWE to quantify climate change in infrastructure design.