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BUILDING STRONG®
Warning from the Past The message, meteorology and myths from the Great West Coast
flooding of 1861- 1862
Larry SchickU.S. Army Corps of Engineers – Seattle District
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What happened in the winter of 1861-1862 ?
Historic flooding Willamette river - Oregon
Historic flooding Northern CaliforniaCentral Valley fills with water
Historic flooding Southern CaliforniaLos Angeles, Orange & San Diego County
flood
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Winter 1861-62Equivalent to 4 major hurricanes plus many
tropical storms
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What is the “Warning from the Past”?Why Care?
Framework for futureextreme floods
Prepare for possibilities
Recognize pattern California simulated major storm/flood
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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 unfoldHistory repeats itself – sort of
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A Smoking Gun ?
Major eruptionDubbi volcano – North AfricaMay 1861
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Largest historic volcanic eruptionin Africa – May 1861
Eritrea
Ethiopia
Red SeaSudan
DubbiVolcano
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Large volcanic eruptionsin the tropics cool Northern
Hemisphere
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Great Flood of 1861 - 1862Myths: confirmed or busted ?
Big Mega StormSnow melt ? Frozen ground ?Hydraulic mining debris?Central Valley Flood?Greatest Flood?
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Great Flood of 1861- 1862Myths: confirmed or busted ?
One Big Mega Storm – No
Series of storms -with a few large ones
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Great Flood of 1861 - 1862Myths: confirmed or busted ?
Snow melt caused flood - NO
greater than normal snow 500 - 3000ft deep snow higher elevationssnow melt typically: 10 – 20% of runoff
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Great Flood of 1861 - 1862Myths: confirmed or busted ?
Greatest California Flood ?
Overall storm season unprecedented
Greater high water marks than 18621805, 1825, 1850, 1852
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Hydraulic mining did it!Nope
Local runoff impacts only
1917 – USGS mining debris study –page 36
Peak debris output - 1885
1862 rainfall
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Great Flood of 1861 – 1862Myths: confirmed or busted ?
Frozen ground caused flood - NO
Cold - but not cold enough, long enough
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Great Flood of 1861 -1862Myths: 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 dataConflicts of dataLimited daily data: Sacramento
San Francisco SonoraNevada City (Red Dog)
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Limited Weather Data
Southern California – no daily data, limited monthly
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Limited Weather Data
Anecdotal - newspapers, books, research, diaries
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Limited Hydro Data
Mainly USGS paleo flood or highwatermarks and estimates
No stream gauging – occasional stage observations
Anecdotal - newspapers, books, research
Peak estimates, unknown volumes
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Information sourcesInformation: recent articles & historic
documents
October 20, 1888
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1860’s Climate & Hydrology
Natural hydrologic system – limited levees & diversions
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California – Paradise Lost90% of the wetlands – gone
Wetlands: flood sponge
Then Now
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1860’s Climate & Hydrology
End of the Little Ice Age – Cool & Wet
Skating the canals – Rotterdam 1825
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1860’s Climate & Hydrology
ENSO Neutral: 1861 – 1862ENSO 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 ?
- narrow, long & moist - attach to incoming Pacific storms- cause intense rainfall & flooding
AR moisture coupled with jet stream
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Weather Pattern for Extreme Rainfall
Atmospheric Rivers
(fall and winter)
Southwest Monsoon
(summer & fall)
Great Plains Deep Convection
(spring and summer)
Spring Front Range Upslope
(rain/snow)
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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 TimesPeople lived near rivers: flat, water supply, transportation, commerce
Economy: agriculture & ranching, mining
California: 500,000 peopleOregon: 50,000 people
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Character of West Coast Winterweather of 1861-1862
Wet pattern shifted north to south
- Nov: West coast - wet and cool
- Early Dec: extreme wet Oregon
- Jan: extreme wet California
- Dec & Jan extreme cold Washington & Oregon
Persistent wet
Waves spin off main low
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November 1861Variable northwesterly storm track
Prime the pump: optimize antecedent conditions
Saturate soilsLow elevation snow High stream flows
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Fort Vancouver, Washington TerritoryDecember 2, 1861 – 7:00 am
Weather entry: 59 degreesnormally 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, ORDec 4 1861
Commerce impacts
Likely atmospheric river
Mid/late Dec – Jan - very cold, snowy
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Willamette Valley drainage
A map
Columbia River
Willamette River
A map
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Early December 1861
Mild
Atmospheric river
Flooding
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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
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Jupiter Pluvius: street name - “sender of rain”
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Willamette FallsHistoric 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
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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
BecomesVery Cold
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Northern California winter rain1861 - 1862
Note: mountains receive 2 - 4 times as much rainfall
1861-1862
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Northern California - WinterHistoric 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
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California Rivers
Sacramento river
American river
San Joaquin river
Santa Ana river
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Atmospheric “Rex” block
Persistent rainy pattern
H
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NW in the Deep FreezeJan 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
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Mid January 1862
Atmospheric River
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January 8-12 and 15-17
1862
AR coreheavy rain
General rainfall
Flood Peak American River Jan 10th318,000 cfsSecond peak ~ 20th
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Northern California Flooding
1862
Inland Lake: 300 miles long, 20 mi wide, 20 ft deep
:Lake SacramentoJanuary 1862
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Flood Waters20-30 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”
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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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January 20-22 1862
Heavy rain Major flood
General rainfall
Heavy rainfall
Flood peakSanta Ana River – Jan 22
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Los Angeles / Orange County - 19381862 was three times as bad
Anaheim's Center Street -1938 flood
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Southern California Flooding – Jan 1862
Antecedent conditions very wetfor 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
100,000 cfs1938
317,000 cfsJan 1862
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Los Angeles County flooded areas 1862
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Aqua Mansa “calm water” – destroyed in 1862Largest settlement between New Mexico and Los Angeles
Inland Orange County -- Santa Ana river, near Colton, California
1930 flooding
“…billows 50 ft high”
late Jan 1862
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Southern California Flooding 1862
Lowland Los Angeles & Orange County
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Additional impacts
Volcano, CA landslide kills seven Colorado River –
400,000 cfs
Salton Sea fills, overflow from Colorado River
Captain of clipper “Prima Donna” logs fresh water offshore – fresh water
fish caught
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Additional impacts
Yuma, AZdestroyed
Carson Valley, NVflooding
Virgin River, UT destroys town
Ventura flooded &
abandoned
Maui, Hawaii: fir tree washes
ashore
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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
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Lessons of the 1861-62 Floods Models will forecast – but not detailsWet antecedent conditions - not one storm
eventDams & levees reduce flood risk – but…Changing flood risk: politics/land use/dams&
levees/climate change
History to repeat – but not exactly
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Warning from the Past Lessons from the Great West Coast
flooding of 1861 – 1862
Never underestimate the power of water
Larry SchickU.S. Army Corps of Engineers – Seattle District