Hydrometeorological Analyses of the June 1903 Heppner, Oregon Flood

In this study, we examine the 14 June 1903 flood that devastated Heppner, Oregon. We summarize and synthesize hydrologic, hydrometeorological and hydraulic analyses of the storm and flood and examine the storm environment through downscaling simulations using the Weather Research and Forecasting model with 20th Century Reanalysis fields serving as lateral boundary conditions. The Heppner flood was produced by an orographic thunderstorm system. The role of thunderstorms as flood agents in the region is not unprecedented, but the magnitude of the flood peak is. We show that, even for “small” storms like the one that produced the Heppner flood, downscaling simulations using 20th Century Reanalysis fields can provide important insights to extreme events. We also use the 20th Century Reanalysis fields to examine the climatology of the storm environment associated with the Heppner Flood.