The New York Times describes the record flood of 1862 (without mentioning it) and says the burning of fossil fuels made it more likely.
“As humans burn fossil fuels and heat up the planet, we have already increased the chances each year that California will experience a monthlong, statewide megastorm of this severity to roughly 1 in 50, according to a new study published Friday. (The hypothetical storm visualized here is based on computer modeling from this study.)
In the coming decades, if global average temperatures climb by another 1.8 degrees Fahrenheit, or 1 degree Celsius — and current trends suggest they might — then the likelihood of such storms will go up further, to nearly 1 in 30.”
The Coming California Megastorm – The New York Times
The deadly 1862 flood that wiped out and reshaped California