Warning from the Past The message, meteorology and myths from the Great West Coast flooding of 1861- 1862
Larry Schick U.S. Army Corps of Engineers – Seattle District BUILDING STRONG®
What happened in the winter of 1861-1862 ? Historic flooding Willamette river - Oregon Historic flooding Northern California Central Valley fills with water Historic flooding Southern California Los Angeles, Orange & San Diego County flood BUILDING STRONG®
Winter 1861-62 Equivalent to 4 major hurricanes plus many tropical storms
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What is the “Warning from the Past”? Why Care? Framework for future extreme floods Prepare for possibilities Recognize pattern
California simulated major storm/flood BUILDING STRONG®
What is the message? Models will forecast, expect unexpected – details? Series of storms – not one storm. Dams and levees will help – and hurt Flood risk changes as events unfold History repeats itself – sort of BUILDING STRONG®
A Smoking Gun ?
Major eruption Dubbi volcano – North Africa May 1861
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Largest historic volcanic eruption in Africa – May 1861 Sudan Red Sea Eritrea Dubbi Volcano Ethiopia
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Large volcanic eruptions in the tropics cool Northern Hemisphere
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Great Flood of 1861 - 1862 Myths: confirmed or busted ? Big Mega Storm Snow melt ? Frozen ground ? Hydraulic mining debris? Central Valley Flood? Greatest Flood?
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Great Flood of 1861- 1862 Myths: confirmed or busted ? One Big Mega Storm – No Series of storms with a few large ones
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Great Flood of 1861 - 1862 Myths: confirmed or busted ?
Snow melt caused flood - NO greater than normal snow 500 - 3000ft deep snow higher elevations snow melt typically: 10 – 20% of runoff
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Great Flood of 1861 - 1862 Myths: confirmed or busted ? Greatest California Flood ? Overall storm season unprecedented Greater high water marks than 1862 1805, 1825, 1850, 1852
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Hydraulic mining did it! Nope Peak debris output - 1885 1862 rainfall
1917 – USGS mining debris study – page 36
Local runoff impacts only BUILDING STRONG®
Great Flood of 1861 – 1862 Myths: confirmed or busted ? Frozen ground caused flood - NO Cold - but not cold enough, long enough
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Great Flood of 1861 -1862 Myths: confirmed or busted ? California Central Valley: a lake – completely flooded
Yes, but not rare event
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Limited Weather Data Pacific NW – Forts No hourly data Conflicts of data Limited daily data: Sacramento San Francisco Sonora Nevada City (Red Dog) BUILDING STRONG®
Limited Weather Data
Southern California – no daily data, limited monthly BUILDING STRONG®
Limited Weather Data
Anecdotal - newspapers, books, research, diaries BUILDING STRONG®
Limited Hydro Data Mainly USGS paleo flood or highwater marks and estimates No stream gauging – occasional stage observations Anecdotal - newspapers, books, research Peak estimates, unknown volumes BUILDING STRONG®
Information sources Information: recent articles & historic documents
October 20, 1888 BUILDING STRONG®
1860’s Climate & Hydrology Natural hydrologic system – limited levees & diversions
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California – Paradise Lost 90% of the wetlands – gone Wetlands: flood sponge
Then
Now BUILDING STRONG®
1860’s Climate & Hydrology End of the Little Ice Age – Cool & Wet
Skating the canals – Rotterdam 1825 BUILDING STRONG®
1860’s Climate & Hydrology ENSO Neutral: 1861 – 1862 ENSO Neutral: West coast most extreme floods
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What is the Cause of Extreme Precipitation on the West Coast ? Pacific storms with atmospheric rivers Atmospheric river
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What is an atmospheric river ?
AR moisture coupled with jet stream
- narrow, long & moist - attach to incoming Pacific storms - cause intense rainfall & flooding BUILDING STRONG®
Weather Pattern for Extreme Rainfall Great Plains Deep Convection Atmospheric Rivers (fall and winter)
(spring and summer) Spring Front Range Upslope (rain/snow)
Southwest Monsoon (summer & fall)
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The Times Civil War in progress Lincoln president Pony Express ends Oct 1861 Trans continental telegraph begins Oct 1861
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America 1861
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The Times People lived near rivers: flat, water supply, transportation, commerce Economy: agriculture & ranching, mining California: 500,000 people Oregon: 50,000 people BUILDING STRONG®
Character of West Coast Winter weather of 1861-1862 Waves spin off main low
- Nov: West coast - wet and cool
- Early Dec: extreme wet Oregon - Jan: extreme wet Wet pattern shifted north California Persistent wet
to south
- Dec & Jan extreme cold Washington & Oregon BUILDING STRONG®
November 1861 Variable northwesterly storm track
Prime the pump: optimize antecedent conditions Saturate soils Low elevation snow High stream flows
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Fort Vancouver, Washington Territory December 2, 1861 – 7:00 am
Weather entry: 59 degrees normally in the 30’s
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Atmospheric river arrives Oregon early Dec 1861
Similar to this -- Feb 7, 1996
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Willamette River - Oregon flood All time record flood Willamette River, OR Dec 4 1861 Commerce impacts Likely atmospheric river Mid/late Dec – Jan - very cold, snowy BUILDING STRONG®
Willamette Valley drainage A map Columbia River
A map
Willamette River
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Early December 1861
Flooding Mild Atmospheric river
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Olympia newspaper - Dec 1861 “ the rain it raineth every day, and every night also – week in and week out, from the rising sun to the going down of same, there is nothing but rain, rain, rain ‘The windows of heaven are opened up.’ Pluvius, grieved at some earth giving wrong, weeps as he would never dry up.” -- Overland Press – Monday - Dec 16, 1861 BUILDING STRONG®
Jupiter Pluvius: street name - “sender of rain”
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Willamette Falls Historic photo Dec 2006 - 100,000cfs (below) Dec 1861 > 600,000 cfs at the falls
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Flat - bedded steamer St Clair
Over Willamette Falls – on purpose BUILDING STRONG®
Willamette River At Salem Dec 4, 1861 Feb 1996 (if no dams)
.
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Portland, Oregon Early December 1861 flood - First and Washington
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December 1861 Becomes Very Cold
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Northern California winter rain 1861 - 1862
1861-1862
Note: mountains receive 2 - 4 times as much rainfall BUILDING STRONG®
Northern California - Winter Historic January flooding December - Wet - 10” (San Francisco) January - Extraordinarily wet – 24” ( S.F.) Very wet antecedent conditions, lowland snow – Heavy rain Jan 9 -12 and 15-17 BUILDING STRONG®
Sacramento river American river
California Rivers
San Joaquin river
Santa Ana river
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Atmospheric “Rex” block
H Persistent rainy pattern
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NW in the Deep Freeze Jan 1862
Seattle – below zero, 2-3 ft of snow Lake Union freezes six inches Columbia and Fraser river freeze Live stock die No communications and supplies 30 plus below zero east of the Cascades BUILDING STRONG®
Mid January 1862
Atmospheric River
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January 8-12 and 15-17 1862
General rainfall
AR core heavy rain Flood Peak American River Jan 10th 318,000 cfs Second peak ~ 20th
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:
Lake Sacramento January 1862
Northern California Flooding 1862 Inland Lake: 300 miles long, 20 mi wide, 20 ft deep
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Flood Waters 20-30 ft deep
Covering telegraph poles in California’s Central Valley
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Flooding In Sacramento - 1862
Legislative temporarily moved “…it appears weather ,water and whiskey had a lot to do with it” BUILDING STRONG®
Sacramento Flooding 1862
“Sacramento was transformed into a sort of frontier Venice”
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American River
January 10, 1862 Regulated peaks
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Southern California Flooding 1862
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Late January Southern California 1862
Wet
Atmospheric river
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Heavy rainfall
January 20-22 1862 General rainfall
Heavy rain Major flood Flood peak Santa Ana River – Jan 22
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Los Angeles / Orange County - 1938 1862 was three times as bad
Anaheim's Center Street -1938 flood
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Southern California Flooding – Jan 1862 Antecedent conditions very wet for a month – 35” in LA Major storm ~ Jan 20th Santa Ana river peak January 22, 1862
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Santa Ana River
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Santa Ana River Watershed
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Santa Ana River Historic Peaks 317,000 cfs Jan 1862
100,000 cfs 1938
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Los Angeles County flooded areas 1862
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Aqua Mansa “calm water” – destroyed in 1862 Largest settlement between New Mexico and Los Angeles
“…billows 50 ft high” late Jan 1862
1930 flooding Inland Orange County -- Santa Ana river, near Colton, California
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Southern California Flooding 1862
Lowland Los Angeles & Orange County
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Additional impacts
Captain of clipper “Prima Donna” logs fresh water offshore – fresh water fish caught
Volcano, CA landslide kills seven
Salton Sea fills, overflow from Colorado River
Colorado River – 400,000 cfs
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Additional impacts
Maui, Hawaii: fir tree washes ashore Carson Valley, NV flooding
Virgin River, UT destroys town Ventura flooded & abandoned
Yuma, AZ destroyed BUILDING STRONG®
Cause of 1861-1862 extreme West Coast flooding Series of storms Intense rain: several atmospheric rivers Optimum antecedent flood conditions: - high background river flows - saturated soils - favorable snowmelt BUILDING STRONG®
Lessons of the 1861-62 Floods Models will forecast – but not details Wet antecedent conditions - not one storm event Dams & levees reduce flood risk – but… Changing flood risk: politics/land use/dams& levees/climate change History to repeat – but not exactly BUILDING STRONG®
Warning from the Past Lessons from the Great West Coast flooding of 1861 – 1862
Never underestimate the power of water Larry Schick U.S. Army Corps of Engineers – Seattle District
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