Why a more developed civilization wasn't here when Spanish then U.S. colonists arrived in California

Why wasn't there something like a Beijing or Shanghai or Tokyo or Seoul here somewhere between Seattle and Los Angeles when settlers first arrived from Spain, Mexico and the original 13 and more colonies of the U.S.?

Because any civilizations that developed here before would have been washed away once every 100 to 200 years like things were washed away in California, Oregon, Washington, Nevada, Arizona and Utah in 1861 and 1862.

So, since this happens every 100 to 200 years no civilization without the level of technology that we have or more could have survived this without deciding to move away likely in ships to another location where it doesn't wash everything away every 100 to 200 years.

Great Flood of 1862 - Wikipedia, the free encyclopedia

en.wikipedia.org/wiki/Great_Flood_of_1862

Wikipedia

Jump to Southern California - [edit]. In Southern California, beginning on December 24, 1861, it rained for almost four weeks for a total of 35 inches at Los  ...

California Megaflood: Lessons from a Forgotten Catastrophe

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Scientific American

Dec 18, 2012 - California Megaflood: Lessons from a Forgotten Catastrophe ... A January 15, 1862, report from the Nelson Point Correspondence described  ...

flood in California - The New York Times

www.nytimes.com/1862/.../the-great-flood-in-calif...

The New York Times

THE GREAT FLOOD IN CALIFORNIA.; Great Destruction of Property Damage $10,000,000. Published: January 21, 1862. Facebook; Twitter; Google+; Email ...

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