California May Be Long Overdue For A Mega Flood(Updated 02-11-17)

A story in the San Francisco Chronicle compares the current weather related flooding to the flooding of 1862  Paul Deanno writes:

. . . ] Over 100 years ago California was in the same boat, literally. The rain started to fall just before Christmas, and it didn’t let up for over 40 days. The Central Valley became a lake.

It was 1862. Leland Stanford was sworn in as California’s 8th governor. But he wouldn’t start his term in Sacramento because California’s capitol city, along with much of the state, was ten feet under water.

Geography Professor and Berkeley Researcher Dr. Lynn Ingram described the flood as ‘a major catastrophe.”

“You couldn’t walk around the streets. It was just people scrambling with row boats and little houses floating away and furniture and cows,” explained Ingram. “[Atmospheric rivers] can carry up to ten Mississippi rivers worth of water vapor from the tropics. It’s like a fire hose.”

So the question is, could it happen again? The answer: yes.

Geographic data indicates California has a mega flood about every 100 to 200 years. So the Golden State is overdue, long overdue for a big storm.

I have written about the great flood before HERE and HERE after reading The West Without Water, a book by Professor Lynn Ingram. According to Ingram, the  megafloods occur  every 100 to 120 years (page 147) not as reported in the Chronicle every 100-200 years. Also from Ingram’s book:

Before the [1862] floods, California state geologist Josiah Whitney had hired an assistant, William Brewer, to help survey the young state’s natural resources. In 1862, Brewer sent a series of letters to his brother on the East Coast describing the surreal scenes of tragedy that he witnessed during his travels in California that winter and spring. Brewer’s letters documented the unprecedented snowfall in November and early December 1861 that blanketed the Sierra Nevada range. The snow did not last long, however, because the same series of warm storms that wreaked havoc along the West Coast also melted the snow and drenched the western slopes of the Sierra Nevada with 60–102 inches of rain. Nevada City, fifty miles northeast of Sacramento, received a total of more than nine feet of rain for the season (whereas the normal rainfall there is fifty-five inches, or just under five feet).

Ingram, B. Lynn; Malamud-Roam, Frances (2013-08-01). The West without Water: What Past Floods, Droughts, and Other Climatic Clues Tell Us about Tomorrow (p. 29). University of California Press.

Does this sound familiar? The Sierra Snow Pack is almost 175% of normal. Halfway through the rainy season, Nevada County rainfall is above normal at 56.08″ The Normal Average Rainfall by end of February is 44.61″ Two to three inches is forecast for the next two days in Nevada City, with five to six in the high Sierra, most falling as rain on the established snowpack, resulting in excessive flooding. We could be on the cusp of the next megaflood!

Update 02-11-17: More from the SF Chronicle:

Is California overdue for biblical, catastrophic flooding? History says it could be

Settlers realized the homes that survived had something in common: They were built in the spots where Native Americans originally put down settlements. Native stories spoke of the Sacramento Valley as an inland sea. For centuries, they’d seen the valley fill with water, and the Nevada City Democrat reported that “Indians living in the vicinity of Marysville left their abodes a week or more ago for the foothills predicting an unprecedented overflow. “

More HERE.

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About Russ Steele

Freelance writer and climate change blogger. Russ spent twenty years in the Air Force as a navigator specializing in electronics warfare and digital systems. After his service he was employed for sixteen years as concept developer for TRW, an aerospace and automotive company, and then was CEO of a non-profit Internet provider for 18 months. Russ's articles have appeared in Comstock's Business, Capitol Journal, Trailer Life, Monitoring Times, and Idaho Magazine.
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4 Responses to California May Be Long Overdue For A Mega Flood(Updated 02-11-17)

  1. Russ says:

    There is some urgency to get the dam strengthened. This from Meteorologist Paul Dorian, Vencore, Inc. vencoreweather.com

    California blitz to continue:

    After a lengthy drought, California has been battered by potentially record-setting rain, with the Northern California region getting 228 per cent more than its normal rainfall for this time of year. The average annual rainfall of about 50 inches had already been overtaken with 68 inches in 2017 alone and another 6+ inches is possible over the next week-to-ten days. The latest computer model forecast of upper-level winds for the next ten days (Monday, 2/13 to Thursday, 2/23) does not hold out much hope for any significant drying in California. Powerful winds in the upper atmosphere (at 250 mb) will continuously pound California and bring copious amounts of moisture from the Pacific Ocean into the state. The total precipitation forecast map by NOAA for the next 7 days indicates more significant rainfall (and snowfall) is likely throughout the state.

    In other words, the atmospheric river of moisture continues to drench California much like it did in 1862 resulting in a mega-flood.

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  2. Russ says:

    Emergency flow over the Oroville Dam at 8:30 this morning.

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  3. Stu says:

    And if you go further back (Geologic time scales) it gets real fun! There are serpentine rocks on top of some local peaks (Mendocino county) that were created out in the ocean from successive decades of deposits from magafloods then compressed, folded and somehow deposited on much younger (geologically speaking) peaks.

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