Flood hazard is a function of the magnitude and spatial pattern of precipitation accumulation.
The sensitivity of precipitation to atmospheric temperature is investigated for idealized extratropical
cyclones, enabling us to examine the footprint of extreme precipitation (surface area where accumulated
precipitation exceeds high thresholds) and the accumulation in different-sized catchment areas. The
mean precipitation increases with temperature, with the mean increase at 5.40%/∘C. The 99.9th percentile
of accumulated precipitation increases at 12.7%/∘C for 1 h and 9.38%/∘C for 24 h, both greater than
Clausius-Clapeyron scaling. The footprint of extreme precipitation grows considerably with temperature,
with the relative increase generally greater for longer durations. The sensitivity of the footprint of extreme
precipitation is generally super Clausius-Clapeyron. The surface area of all precipitation shrinks with
increasing temperature. Greater relative changes in the number of catchment areas exceeding extreme
total precipitation are found when the domain is divided into larger rather than smaller catchment areas.
This indicates that fluvial flooding may increase faster than pluvial flooding from extratropical cyclones in a
warming world. When the catchment areas are ranked in order of total precipitation, the 99.9th percentile is
found to increase slightly above Clausius-Clapeyron expectations for all of the catchment sizes, from 9 km2
to 22,500 km2. This is surprising for larger catchment areas given the change in mean precipitation. We
propose that this is due to spatially concentrated changes in extreme precipitation in the occluded front