EOTW #7 The Great Flood of 1862

During December 1861 in California, it started raining and raining and raining and snowing in the mountains. After approximately two decades of drought, it rained for approximately four months, depositing so much water that massive regions in California flooded. Large portions of the Central Valley flooded, and approximately 66 inches of rain fell on typically arid Los Angeles. The result was huge losses of cattle from the ranch lands (1/4 of the total head in the state), houses and buildings due to widespread, and often very deep, flooding.  Sacramento, the state’s capital, was submerged in water. Flooding was extensive over several western states, including Oregon and Arizona. The phenomena responsible is called an “atmospheric river”.  Just this week, an atmospheric river delivered significant rain to the already vulnerable regions around Santa Barbara and Ventura, resulting in renewed called for evacuations due to possible mudflows in regions impacted by the Thomas fire. For this EOTW comment assignment, read the first two articles below. I include the USGS website as another tool you can use to learn more about the potential for future mega flooding in the state, as well as maps and assessments of vulnerable populations. Then, answer the following questions:

1) What are atmospheric rivers? About how often do megafloods impact the California and western states regions?

2) Approximately how extensive was the 1861-62 event in terms of geography? (ie which states and countries were impacted)?

3) How well do you think the public is aware of the mega flood hazard, compared with earthquake hazards, in California and other western states?

http://www.noaa.gov/stories/what-are-atmospheric-rivers

https://www.scientificamerican.com/article/atmospheric-rivers-california-megaflood-lessons-from-forgotten-catastrophe/

https://geography.wr.usgs.gov/science/mhdp/arkstorm.html

17 thoughts on “EOTW #7 The Great Flood of 1862”

  1. These natural cycles are really interesting to me! They occur in nature, as well as geology.

    1. Atmospheric rivers are relatively narrow, but long, bands of moisture in the atmosphere. They move from the tropics, bringing rain/humidity to other, more arid regions. Mega floods in the western states occur every 100-200 years.

    2. The flooding that occurred in 1861-62 was very extensive. The flooding was in California, Arizona, Utah, Oregon, and parts of mexico.

    3. I don’t think the public is very aware of the flood hazard in California. Most of the news results in drought. That seems to be what most people focus on. And earthquakes. I think humans are have a fairly short term memory, and there hasn’t been many serious floods in that part of the world for a generation or so. But people are old enough to remember earthquakes and fires.

  2. 1) What are atmospheric rivers? About how often do megafloods impact the California and western states regions?
    Atmospheric Rivers are portions of the atmosphere that carry large amounts of water vapor. They in very general terms transport water vapor from warm tropic-like waters approx one mile above the ocean depositing the water vapor in the form of rain and snow when the development of high winds occurs.

    2) Approximately how extensive was the 1861-62 event in terms of geography? (ie which states and countries were impacted)?
    The greater west coast was affected. Oregon, California, Arizona, and Mexico all had devastating flooding

    3) How well do you think the public is aware of the megaflood hazard, compared with earthquake hazards, in California and other western states?
    I would say as a whole that Californians are totally unaware of the flood of 1861. I Have lived here my whole life and never heard of it till now. In addition, it’s probably needless to say that there is a “little” more than 500,000 people in California. The central valley that became an inland sea is the cheap affordable housing now. The cattle ranching has long been decimated but much of the central valley is now farmland producing significant portions of the United States fresh fruit.

  3. 1) What are atmospheric rivers? Atmospheric rivers are columns of water vapor in the sky. They form over the tropics and are transported in the atmosphere like rivers in the sky. As these “rivers” make contact with the earth, the water is released in the form of precipitation like snow or rain. Depending on their intensity, they can even cause mud slides or severe flooding. About how often do megafloods impact the California and western states regions? Every 100-200 years. These atmospheric rivers stretch from nearly a kilometer above the earth and thousands of kilometers in length.

    2) Approximately how extensive was the 1861-62 event in terms of geography? (ie which states and countries were impacted)? The economy of the state was devastated as a result of the flooding. Food became scarce as crops and cattle were obliterated. Not only did California become bankrupt, but lives were lost as well. Thousands lost their lives to the flooding as new bodies of water formed in the interior of California. Canada, the United States of America and Mexico were effected by the storm. Oregon, Washington, California, Arizona and even a small part of southwestern Utah (the portion of south west Utah that is part of the Mojave Utah.

    3) How well do you think the public is aware of the mega flood hazard, compared with earthquake hazards, in California and other western states? Considering that Los Angeles and Sacramento were largely effected by flooding, and there are millions of people there, I would say that California is grossly unprepared for this event. Especially compared to earth quakes as they have experienced them in recent decades. They have invested in EEWS that help mitigate the hazards with flooding. California is so focused on problems associated with the drought that they cannot see what history has to tell them. Not only would a new atmospheric river be more intense but more lives would be lost. The ability of the earth to become saturated and absorb the rain fall is inhibited by asphalt and concrete jungles.

    1. good point about the focus on drought. I think it is difficult to think beyond the 3-5 year timeframe. However, these events are as much a part of CA climate as drought.

  4. 1) What are atmospheric rivers? About how often do megafloods impact the California and western states regions?

    An atmospheric river is a zone in the atmosphere that holds a large amount of water (basically the amount at the mouth of the Mississippi River according to the NOAA website). The Scientific American website says that a Megaflood happens at least once every 100-200 years in California and the surrounding states.

    2) Approximately how extensive was the 1861-62 event in terms of geography? (ie which states and countries were impacted)?

    the 1861-1862 damages destroyed a quarter of California’s economy, forcing California into bankruptcy. Arizona and Oregon were also affected by the heavy rains.

    3) How well do you think the public is aware of the megaflood hazard, compared with earthquake hazards, in California and other western states?

    I feel people are ill-prepared compared to the earthquake hazards in California and along the west coast due to the fact that it is an overtime hazard. Unless there is flash flooding, people don’t see the danger of it raining for several days until it is too late.

  5. An atmospheric river is a large stream of dense water vapor that transports a large portion of the moisture in the air.
    Megafloods impact California and the western region of the US about every 100-200 years.

    Oregon, Utah, California, Arizona, and Mexico were impacted by the event in 1861-1862.

    Personally, I feel that the possible impacts from megaflood events are understated when looking at potential disasters that could impact California and the west coast. Everyone knows about the San Andreas fault, but nobody knows that the region is overdue for a massive flood. Hopefully through outreach, scientific foundations will be able to notify the public of the more realistic dangers that could impact them.

  6. 1. Atmospheric rivers are weather systems that can transport a plume of condensed water vapors from the tropics, such as Hawaii, across the ocean to land. They can be a mile up into the atmosphere and thousands of miles long. As the systems reaches land, they often release the water vapors in the form of snow or rain. The atmospheric rivers impact the western regions approximately every 1 to 2 centuries creating extreme rainfall and flooding. These massive floods can induce mudslides, disrupt travel and communication and cause disastrous loss of life and property.

    2. The 1861-1862 floods affected many regions from Mexico to Canada. Areas affected included Mexico, California, Oregon, Washington, British Columbia, Nevada, Utah and Arizona. Water was 30 feet deep in some areas. Sacramento, California had flooding for 6 months. Even the Mojave Desert had lakes of water.

    3. Although mudslides are a real hazard that the people in California live with, they may not realize the dangers or extent of mega flooding that can occur every 100-200 years. Earthquakes are the prominent hazard that seems more vastly known about on the west coast today. We live in a ‘today’ and ‘now’ world where we are only concerned about what affects us right now. We tend to quickly forget these type of catastrophic hazards after only a short period of time. People get concerned when the hazard is real time and can sometimes forget that being prepared for that hazard is their best defense. Long term planning and building in areas not as susceptible to these hazards can be lifesaving.

  7. 1. What are atmospheric rivers? About how often do megafloods impact the California and western states regions?

    Atmospheric rivers are narrow columns of condensed water vapor, usually between 250-375 miles wide (NOAA, 2015). These rivers move with the weather and are responsible for 30-50% of annual West Coast precipitation. Every 100-200 years atmospheric rivers cause massive floods in California and western states.

    2. Approximately how extensive was the 1861-62 event in terms of geography? (ie which states and countries were impacted)?

    1861s mega-flood affected California, Oregon, Washington, British Columbia, northern Mexico, Utah, Arizona, and Nevada (Ingram, 2013).

    3. How well do you think the public is aware of the mega flood hazard, compared with earthquake hazards, in California and other western states?

    Although most Americans are aware of floods, earthquakes, and other weather phenomenon, I believe most people are naively optimistic about personally experiencing a disaster. Cognitive neuroscientist Tali Sharot explains that eighty percent of people have “optimism bias”, an illusion where someone tends to over-estimate the likelihood that they will experience positive events in their lifetime, and under-estimate the risk of exposure to bad-events (Sharot, 2012).

    References
    Ingram, L. (2013, January 1). California Megaflood: Lessons from a Forgotten Catastrophe. Retrieved from Scientific American: https://www.scientificamerican.com/article/atmospheric-rivers-california-megaflood-lessons-from-forgotten-catastrophe/
    NOAA. (2015, December). What are atmospheric rivers? Retrieved from NOAA: http://www.noaa.gov/stories/what-are-atmospheric-rivers
    Sharot, T. (2012). The optimism bias. Retrieved from TED: https://www.ted.com/talks/tali_sharot_the_optimism_bias#t-36813

  8. Atmospheric rivers are long, narrow, flowing-columns in the atmosphere that transport condensed water vapor from the tropics. These regions are responsible for producing significant amounts of rain and snow when they move inland. The vapor filled column sweeps over mountains, which forces the air to rise and cool which results in heavy precipitation. The West coast of the United States is impacted by megafloods every 100-200 years.

    The 1861-62 event impacted an extensive portion of the American west including Washington State, Oregon, California, Nevada, Utah, and Arizona. Additionally British Columbia, Canada and parts of Northern Mexico were also affected.

    I don’t think the public is aware of the megaflood hazard. I think the main reason the public is unaware is the difference in occurrence rates. Earthquakes are a common occurrence for California and other western states. Earthquakes occur along the west coast countless times a day so they are more upfront in the publics mind. Additionally the systems in place to detect and alert earthquakes get significant funding and attention. On the other hand, the 100-200 year megaflood frequency makes the hazard seem less likely and less of a threat.

  9. 1) What are atmospheric rivers?
    Atmospheric Rivers are columns of water vapor that moves inland over mountain ranges. These systems produces heavy amounts of rain and snow. As the system moves in, the air rises and cools to create excessive amounts of precipitation across the western portion of the U.S. These systems are known for carrying water vapor equivalent of 7.5-15 times more than the average flow of water at mouth of the Mississippi River.
    Megafloods impact California and western states approximately every 200 years.

    2) Approximately how extensive was the 1861-62 event in terms of geography? (ie which states and countries were impacted)?
    California, Oregon, and Nevada were the hardest hit areas. Other areas impacted were: Idaho, Utah, Washington, New Mexico, Canada and Mexico.

    3) How well do you think the public is aware of the mega flood hazard, compared with earthquake hazards, in California and other western states?
    I personally believe, this is something that has been long forgotten about. As a kid, I remember my Dad telling me a story about a town in California that was completely submerged. As we passed by this area, he described how people were living their life, but due to so much rain all was lost -including a train. I think people become complacent, and over time the stories did not get passed down and were forgotten. Unfortunately, this future storm could be blamed on Climate Change when in fact it is a 200 year storm.( of course, climate change can strengthen the storm, but that is for another discussion.) I think proper education, and preparing communities/ residents is critical in case we see one in the 25 years.

    1. Interesting that you remember learning about this from your Dad! I had never heard of this event before teaching this course and I grew up in So. Cal. – was there a part of your family that was impacted?

  10. 1) What are atmospheric rivers? About how often do megafloods impact the California and western states regions?

    An atmospheric river is a long, thin section in the atmosphere that transport humid air from the tropics to temperate and Mediterranean regions of the world. In Oregon, forecasters on TV would call this the “Pineapple Express” when one was going to strike the region. These were the most miserable weather pattern as the rain would not let up for days, unlike other weather patterns. In addition, it often times melted snow on smaller mountains, and brought wet and very heavy snow to higher points on larger mountains like Mt. Hood. It also poses a risk by increasing landslide chances in addition to flooding.

    2) Approximately how extensive was the 1861-62 event in terms of geography? (ie which states and countries were impacted)?

    This event was very extensive because it impacted the west coast of North America including Mexico, California, Oregon, Washington, and British Columbia.

    3) How well do you think the public is aware of the mega flood hazard, compared with earthquake hazards, in California and other western states?

    Having lived in Oregon, I think that people are more aware to flooding hazards in the area, especially if you live in a neighborhood more prone to flooding. Localized flooding is seen most winters, which is definitely noticed by local residents. Earthquakes on the other hand occur very often, leading people to forget about the lurking danger.

  11. 1) What are atmospheric rivers? About how often do megafloods impact the California and western states regions?
    “Atmospheric rivers are relatively long, narrow regions in the atmosphere – like rivers in the sky – that transport most of the water vapor outside of the tropics. These columns of vapor move with the weather, carrying an amount of water vapor roughly equivalent to the average flow of water at the mouth of the Mississippi River. When the atmospheric rivers make landfall, they often release this water vapor in the form of rain or snow.”(NOAA). Megafloods impact the California and western states regions about every 100-200 years.

    2) Approximately how extensive was the 1861-62 event in terms of geography? (ie which states and countries were impacted)?
    This megaflood impacted California greatly. This flood turned parts of the state into inland seas and took months to subside. The reading noted that thousands of lives were lost due to this storm. This storm impacted the western region of the united states including parts of Mexico and Canada.

    3) How well do you think the public is aware of the mega flood hazard, compared with earthquake hazards, in California and other western states?
    In general, I feel as though most of California is unaware of the mega flooding hazard. This is even the first I have heard of it! I have worked on ranches in California during severe droughts and all we ever did was wish for floods. I feel as though many residents of California and those western states are more familiar with hazards that happen far more frequently.

  12. The floods of 1861-62 were very extensive, reaching as far as British Columbia, Canada and northern Mexico. The flooding also occurred in parts of Oregon, Washington, Nevada, Utah and Arizona. What the 1861-62 flooding events that swept the American West were caused by, are atmospheric rivers. Long narrow regions in the atmosphere bring warm moisture in from the tropics near Hawaii to the West Coast, and once these “rivers” make landfall, they release the moisture in rain or snow.

    I think the public is very unaware of the massive flooding that caused so much damage. After reading the Scientific American article I asked a coworker from California, who is a proud history nut and who’s ears perk up whenever California is mentioned, if he had ever heard of the flood. The response was a blank stare then “I’ve never heard that before, what are your sources, who told you that?” Because the megafloods don’t impact the area frequently, and only every 200-300 years many residents forget about the hazards flooding can create.

  13. 1) What are atmospheric rivers? About how often do megafloods impact the California and western states regions?

    Atmospheric rivers are long, narrow regions in the atmosphere that transport most of the water vapor outside of the tropics. Atmospheric rivers release rain and snow when they make landfall. Megafloods impact the west coast every 100-200 years.

    2) Approximately how extensive was the 1861-62 event in terms of geography? (ie which states and countries were impacted)?

    The 1861-62 megaflood impacted the West coast of the U.S., Mexico, and Canada. California was impacted the most “turning enormous regions of the state into inland seas for months, and taking thousands of human lives.” (Ingram 2013)

    3) How well do you think the public is aware of the mega flood hazard, compared with earthquake hazards, in California and other western states?

    I think that the public is extremely unaware of the event, especially since it occurred so long ago. But, immediately after the flood, Sacramento undertook a long term project where the raised the downtown district by 10-15 feet. Usually when you hear about floods on the news that were caused by a hurricane or a tsunami. I think that the public knows more about these types of disasters and earthquakes than they do about floods caused by heavy rainfall.

  14. 1. Atmospheric Rivers are long, narrow bands of the atmosphere (kind of like a jet stream) that cary significantly more water vapor than the surrounding atmosphere. These “rivers” carry water vapor from tropical areas from the south (in the Northern Hemisphere) northward onto continents. Mega floods impact the west coast every 100-200 years.

    2. Mexico, California, Oregon, Washington, British Columbia, Nevada, Utah and Arizona were all affected by the megaflood in 1861-1862.

    3. Having spent a lot of time in Oregon, I never once have heard somebody refer to a life threatening flood. All the catastrophic buzz in that area (and including California) is the “big one” evidently coming from the San-Andreas Fault. Controversially, the city of Sacremento raised their downtown area by 10-15 feet after the mega flood, so maybe they know more than one can assume, but that was over 100 years ago…

  15. 1) What are atmospheric rivers?

    Atmospheric rivers are long, dense “jet stream like” rivers of water vapor around one mile into the atmosphere. They form south, over the tropics and are transported to cooler areas in the north. As these monsters hit unfavorable air over land, the water is released in the form of precipitation like snow or rain. Depending on their intensity, and can cause unpredictable, heavy rainfall over large areas causing quick and extremely dangerous flooding. The western region of the US produces Mega—floods about Every 100-200 years.

    2) Approximately how extensive was the 1861-62 event in terms of geography? (ie which states and countries were impacted)?

    United States of America with California, Oregon, Washington, Arizona and a small part of southwestern Utah. Astonishingly, even as far south as Mexico was effected by the storm.

    3) How well do you think the public is aware of the mega flood hazard, compared with earthquake hazards, in California and other western states?

    Sadly, I don’t think anyone could fathom the potential an event like the 1861 inundation. With concrete like surface areas in California, and other western states, it would be devastating. I can only imaging given the population increase since then, the casualty count would be astronomical. The fact that we have not seen an event of this magnitude, I find it hard to believe much of the public would heed the warning. There is not enough education on cyclic weather events of a historic nature, and when it comes up, people seem to think if they have never experienced it in their lifetime, it must be an exaggeration.

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