California's 1862 Megaflood: What If It Happened Again?

This film is a hypothetical scenario: the storms that flooded California in the winter of 1861–62, arriving again over the state as it is today. In January 1862 the Central Valley became an inland sea about 300 miles long, and the new governor was rowed to his own inauguration. Nearly 150 years later, the Geological Survey built a storm of the same kind to plan for. What would that winter do to the California of today? The scenario in this film is built from the record of the 1861–62 floods, the U.S. Geological Survey's ARkStorm scenario of 2011, and the 2022 ARkStorm 2.0 study of the same kind of storm in today's climate. IN THIS FILM Why was California's capital built where the rivers meet? How did a governor end up rowed to his inauguration? Who counted the dead of the winter of 1862? What is an atmospheric river, and why do several in a row matter? What does the sea floor off Santa Barbara remember? What would the same storm cost California today? Subscribe to Earth in Hindsight for the films still to come. CHAPTERS 0:00 Introduction 1:21 A dry state and the first rain 9:13 The inland sea 17:30 From the mines to the deserts 25:08 What the winter cost 33:07 A river in the sky 41:46 The storms since 50:49 ARkStorm, the southern storm 58:46 ARkStorm, the valley fills again 1:06:05 The odds, and the bypass SOURCES Overview of the ARkStorm Scenario, Open-File Report 2010-1312 (U.S. Geological Survey, 2011) — https://pubs.usgs.gov/publication/ofr... ARkStorm: California's other "Big One" (U.S. Geological Survey, 2011) — https://www.usgs.gov/centers/pcmsc/ne... Design and quantification of an extreme winter storm scenario for emergency preparedness and planning exercises in California (Natural Hazards, 2012) — https://link.springer.com/article/10.... ARkStorm 2.0: Climate change is increasing the risk of a California megaflood (Daniel Swain, Weather West, 2022) — https://weatherwest.com/?p=16626 California Megaflood: Lessons from a Forgotten Catastrophe (Scientific American) — https://www.scientificamerican.com/ar... Up and Down California in 1860–1864, The Rainy Season (William H. Brewer, letters of 1862) — https://www.yosemite.ca.us/library/up... What are atmospheric rivers? (NOAA) — https://noaa.gov/stories/what-are-atm... A scale to characterize the strength and impacts of atmospheric rivers (Bulletin of the American Meteorological Society, 2019) — https://pubs.usgs.gov/publication/702... A Large California Flood and Correlative Global Climatic Events 400 Years Ago (Quaternary Research, 1998) — https://www.cambridge.org/core/journa... Floods of January and February 1969 in Central and Southern California (U.S. Geological Survey, 1969) — https://pubs.usgs.gov/unnumbered/7026... February 1986 storms (National Weather Service, California Nevada River Forecast Center) — https://www.cnrfc.noaa.gov/storm_summ... Oroville Dam (California, 2017), case study (Association of State Dam Safety Officials) — https://damfailures.org/case-study/or... City-Wide Historic Context (City of Sacramento) — https://www.cityofsacramento.gov/cont... When the Floods Came (USC Dornsife) — https://dornsife.usc.edu/news/stories... Breaking the pattern: Systemwide improvements aim to prepare Sacramento for future storm events (U.S. Army) — https://www.army.mil/article/282274/b... — About this film: Earth in Hindsight makes documentary films about natural disasters. This film contains a hypothetical scenario. The event it imagines has not happened. The scenario is built from the hazard's own record and from the published models and monitoring agencies listed above, and estimates are described as estimates. Archive pictures are captioned on screen. All other pictures are illustrative, a mix of licensed footage and digitally created reconstruction. For the current status of any hazard, consult the agency responsible for monitoring it. #GreatFloodOf1862 #WhatIfARkStorm #FloodDocumentary