Thursday, December 06, 2012
It isn't often these days that Scientific American gets anything right but as the saying goes "even the blind squirrel..."
The intense rainstorms sweeping in from the Pacific Ocean began to pound central California on Christmas Eve in 1861 and continued virtually unabated for 43 days. The deluges quickly transformed rivers running down from the Sierra Nevada mountains along the state’s eastern border into raging torrents that swept away entire communities and mining settlements. The rivers and rains poured into the state’s vast Central Valley, turning it into an inland sea 300 miles long and 20 miles wide. Thousands of people died, and one quarter of the state’s estimated 800,000 cattle drowned. Downtown Sacramento was submerged under 10 feet of brown water filled with debris from countless mudslides on the region’s steep slopes. California’s legislature, unable to function, moved to San Francisco until Sacramento dried out—six months later. By then, the state was bankrupt.
-----Worse, even Wikipedia contributes useful historical perspective:
The city of Sacramento suffered the worst damage due to its levee, which lay in a wide and flat valley at the junction of the American and Sacramento Rivers. When the floodwaters entered from the higher ground on the East, the levee acted as a dam to keep the water in the city rather than let it flow out. Soon the water level was 10 feet higher inside than the level of the Sacramento River on the outside. Dozens of wood houses, some two stories high, were simply lifted up and carried off by the flood, as was "all the firewood, most of the fences and sheds, all the poultry, cats, rats and many of the cows and horses". A chain gang was sent to break open the levee, which, when it finally broke, allowed the waters to rush out of the city center and lowered the level of the flooding by five to six feet. Eventually the waters fell to a level on a par with the lowest part of the city.
The SciAm article even includes a graphic of what the Central Valley lake would cover today. I was also impressed by the almost offhand observation that overdrafting the aquifers has reduced AGL by 30 feet.
Note: I am of two opinions wrt to Wikipedia. Fine for most name/date events. Not so good when it comes to why. This entirely natural event would be a centerpiece of a CAGW claim if it had happened recently.