Warning from the Past – The Message, Meteorology, and Myths form the Great West Coast Winter of 1861-1862

The extreme flooding and cold of 1861-62 was like nothing ever documented for the West Coast of the United States. The two month onslaught of winter storminess was relentless. In an eight week period, at least six major storms pummeled the West Coast. From southern Washington State to Southern California, the flooding was so extreme, the high water marks of many major Western rivers remain records to this day.   The core of the extreme winter was actually a series of storms from early December 1861 to late January 1862. The severe weather affected Washington, Idaho, Oregon, California, Nevada, Utah and Arizona. Snows were deep, cold was intense and rainfall extreme.  The floods were catastrophic.  The Central Valley of California filled to a 300 mile long lake. The lower Colorado River peaked at 400,000 cfs. Fresh water “floated” on top of the near offshore waters of California. The author isolates several major atmospheric river weather patterns at the root of this sequence of unsettled weather. This investigation also dispels the common myths of 1861-62 flooding, then proposes lessons learned. (KEYWORDS: 1861-62, flooding, Pacific coast, California Central Valley, little ice age)