Floods

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