Got Flippers? California Mega Flood

Submitted by David Trammel on Mon, 11/15/2021 - 16:30
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The Green Wizard's Cafe

Something to add to the problems of the future, catastrophic flooding in the California valley destroying a large part of the American and World agriculture.

"The Biblical Flood That Will Drown California"

"...a growing body of research shows there’s a flip side to the megadroughts Central Valley farmers face: megafloods. The region most vulnerable to such a water-drenched cataclysm in the near future is, ironically enough, the California’s great arid, sinking food production basin, the beleaguered behemoth of the US food system: the Central Valley. Bordered on all sides by mountains, the Central Valley stretches 450 miles long, is on average 50 miles wide, and occupies a land mass of 18,000 square miles, or 11.5 million acres—roughly equivalent in size to Massachusetts and Vermont combined. Wedged between the Sierra Nevada to the east and the Coast Ranges to the west, it’s one of the globe’s greatest expanses of fertile soil and temperate weather. For most Americans, it’s easy to ignore the Central Valley, even though it’s as important to eaters as Hollywood is to moviegoers or Silicon Valley is to smartphone users. Occupying less than 1 percent of US farmland, the Central Valley churns out a quarter of the nation’s food supply."

Given how often I keep hearing on the weather channels of a "atmospheric river of water headed towards the West Coast" almost every year now, will it be just a matter of time until one such weather system sticks around and floods the entire Valley, causing billions of dollars in damage and empty shelves across the world?

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mountainmoma

Tue, 11/16/2021 - 00:40

The whole central valley was a wetland area before the incoming water was dammed and the area drained. Of course it is vulnerable to floods. All those farms should be wetlands with California Tule Elk, Salmon and other fish and wetland birds, the birds used to blot out the sky.

pygmycory

Wed, 11/17/2021 - 20:19

Wow. That will be a massive mess whenever it happens.

It hits a bit closer to home than normal too. Southern BC is currently pretty much cut off from Alberta by land right now, short of going through the US. Why? Because an atmospheric river last weekend dropped a month's worth of rain in about 24 hours. Cue landslides and massive flooding. The highways are cut and damaged. And Merritt is currently evacuated.

I wonder what we've had in the way of giant floods? In terms of giant past floods I normally think of melting glaciers or ice sheets. When a meltwater lake forms, and the ice dam breaks, that has been catastrophic. Biblical flood legend level. But we don't have continental-scale glaciers in North America any more to produce things like Lake Agassiz.

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David Trammel

Thu, 11/18/2021 - 04:56

I wonder how susceptible the West Coast of Canada is to landslide driven tsunamis?

https://www.nps.gov/articles/aps-18-1-2.htm

There have been some very damaging local events from landslides situated near bodies of water. If enough rain happens, this could trigger one.

pygmycory

Thu, 11/18/2021 - 12:46

I think it depends on the size of the water body, the distance from the landslide site to the place you're worried about, and their relative geometry. It's more of an issue in confined bodies of water like lakes than the ocean. So towns on narrow fjords and lakes need to worry more than say, the fraser delta or Victoria. I think the salish sea is simply too big for a landslide to have much impact. The landslide can only displace so much water. Now an earthquake, that is a different matter! Or a giant methane clathrate eruption causing massive underwater landslides down the continental shelf.