High Quality Content by WIKIPEDIA articles! The Great Flood of 1862 or Noachian Deluge was the largest flood in the recorded history of Oregon, Nevada and California, occurring from December 1861 to January 1862. It was preceded by weeks of continuous rains (or snows in the high elevations) that began in Oregon in November 1861 and continued into January 1862. This was followed by record quantitative precipitation in January 9-12th, which contributed to a flood which extended from the Columbia River southward in western Oregon and through California to San Diego, and extended as far inland as Idaho in Washington Territory, Nevada and Utah in Utah Territory and Arizona in western New Mexico Territory.