The catastrophe modeling of the USGS extrapolates current damage$ based upon the scenario of the California floods of 1861-1862. Quoting directly from the Southern California quarterly Volume 1 (1884) [Google Books is awesome]: “During the months of December, 1861, and January, 1862, according to a record kept at San Francisco, 35 inches of rain fell, and the fall for the season footed up nearly 50 inches.”
“It began raining on December 24,1861, and continued for thirty days, with but two slight interruptions. The Star published the following local: ” A Phenomenon—On Tuesday last the sun made its appearance. The phenomenon lasted several minutes and was witnessed by a great number of persons.” For nearly three weeks there was no mail; some wag labeled the postoffice, ” To Let.”
“After the deluge, what ? The drought. It began in the fall of 1862, and lasted to the winter of 1864-65. The rainfall for the season of 1862-63 did not exceed four inches, and that of 1863-64 was even less. In the fall of 1863 a few showers fell, but not enough to start the grass. No more fell until March. The cattle were dying of starvation. Herds of gaunt, skeleton-like forms, moved slowly over the plains in search of food.”
“If there is one characteristic of his State, of which the true Californian is prouder than another, it is its climate. With his tables of mean temperature and records of cloudless days and gentle sunshine, he is prepared to prove that California has the most glorious climate in the world. Should the rains descend and the floods prevail, or should the heavens become as brass, and neither the former nor the latter rains fall, these climatic extremes, he excuses on the plea of exceptional years.” (Guinn 1889)
Still quoting (actually just copying b/c the prose cannot be topped)
Here and there, singly or in small groups, poor brutes, too weak to move on, stood motionless with drooping heads slowly dying of starvation. It was a pitiful sight In the long stretch of arid plain between San Gabriel and the Santa Ana there was one oasis of luxuriant green. It was the vineyards of the Anaheim colonists kept green by irrigation. The colony lands were surrounded by a close willow-hedge, and the streets closed by gates. The starving cattle, frenzied by the Bight of something green, would gather around the inclosure and make desperate attempts to break through. A mounted guard patrolled the outside of the barricade day and night to protect the vineyards from incursion by the starving herds.
The loss of cattle was fearful. The plains were strewn with their carcasses. In marshy places and around the cienegas, where there was a vestige of green, the ground was covered with their skeletons, and the traveler for years afterward was often startled by coming suddenly on a veritable Golgotha—a place of skulls—the long horns standing out in defiant attitude, as if protecting the fieshless bones. It is said that 30,000 head of cattle died on the Stearns Ranchos alone. The great drought of 1863-64 put an end to cattle raising as the distinctive industry of Southern California.
…and more on the records of California floods…
In looking over the record of floods we find, as a rather remarkable coincidence, that for a period of fifty years, a flood has occurred every tenth year. Beginning with the season of 1811 and 1812 we find floods occurred in 1822-32—42-52 and 62. To establish a theory of decadal floods there should have been one in 1872 and in 1882, but both these were dry years—floods occurring in 1873-74 and 1883-84. Possibly the great flood of 1868 so confused Jupiter Pluvius that he lost his reckoning.
Let’s go back to 1852:
In January, 1850, the ” Argonauts of ’49 ” had their first experience of a California flood. The valley of the Sacramento was like an inland sea, and the city of Sacramento became a second Venice. But, instead of gondolas, the honest miners navigated the submerged streets in wagon-boxes, bakers’ troughs, crockery crates, and on rafts made of whisky-kegs. Whisky in hogsheads, whisky in barrels and whisky in kegs floated on the angry waters, and the gay gondolier, as he paddled through the streets, drew inspiration for his song from the bung-hole of his gondola.
A HISTORY OF CALIFORNIA FLOODS AND DROUGHT.
BY J. M. GUINN.
• [Read March 4, 1889.]
If there is one characteristic of his State, of which the true Californian is prouder than another, it is its climate. With his tables of mean temperature and records of cloudless days and gentle sunshine, he is prepared to prove that California has the most glorious climate in the world. Should the rains descend and the floods prevail, or should the heavens become as brass, and neither the former nor the latter rains fall, these climatic extremes, he excuses on the plea of exceptional years. It is with the record that these exceptional years have made that I propose to deal in this paper. Equable conditions, whether climatic or social, have nothing of the tragic in them, and history delights in the tragic. While Central and Southern California have been about equally affected by floods and droughts, my record of their effects applies principally to Southern California.
For the first fifty years after the settlement of California the weather reports are very meagre. The padres had no Signal Service Bureau and compiled no meteorological tables of atmospheric phenomena, although the state of the weather was undoubtedly a topic of deep interest to the pastoral people of California. To the dons and the padres, with their cattle on a thousand hills, and their flocks and herds spread over the plains, an abundant rainfall meant prosperity ; a dry season death to their flocks and consequent poverty. We can imagine with what anxiety they scanned the heavens for rain signs as the waning months of the rainy season passed away, leaving but a scanty supply of moisture. The weather prophet, with his portents and omens, was without honor at such times. A flood might be a temporary evil, but like the overflow of the Nile, a year of plenty always followed; whilst the dreaded dry year was an evil unmixed with good.
The earliest record of a flood that I have been able to find is a brief mention of one that occurred in 1811. In 1815 occurred a great flood that materially changed the course of the Los Angeles River within the city limits. The river abandoned its former channel and flowed west of the suertes or planting fields of the first settler, its new channel followed very nearly the present line of Alameda Street. The old fields were washed away or covered with sand, and new fields were located in what is now the neighborhood of San Pedro Street.
This record of California floods, I confess, appears rather formidable and might even be considered damaging to the good name of our State, were it not that our floods, like everything else in our State, can not be measured by the standard of other countries. We are exceptional even in the matter of floods. While floods in other lands are wholly evil in their effects, ours, although causing temporary damage, are greatly beneficial to the country. They fill up the springs and mountain lakes and reservoirs that feed our creeks and rivers, and supply water for irrigation during the long dry season. A flood year is always followed by a fruitful year. The disastrous effects of drought disappeared with the decadence of the cattle and sheep industries. Increased facilities for irrigation, the development of water by tunneling into the hills, artesian wells, the building of reservoirs for water storage, and the more economic use of water, have done much to counteract the evil effects of the dreaded dry year.”
end quotation (Guinn 1889).