• Maps of precipitation uncertainty over the  mountainous Western United States: Following Henn et al. 2018, these are maps of the differences in precipitation accumulations among popular gridded precipitation datasets. The differences are a proxy for how uncertain gridded precipitation estimates are, and show that uncertainty is high (>400 mm/yr) in mountainous terrain, and increases with elevation and in the lee of major ranges (>20-30%). Click link below to download GeoTIFF grids of absolute differences (mm) and relative differences (fraction); see Henn et al. 2018 for details on methodologies..