Well, you just take that, New Orleans!

If the greatest flood ever recorded in California happened in 1862, wouldn't it be hard to blame another of its size on the global warming now occurring? The damage such a flood would cause, quite aside from its cause, would be the result of the state's contemporary population, 39.5 million, compared with the half million in the state in 1862. And these aren't 39.5 million sitting ducks. They don't fly and don't float. But, according to our business and political leaders, they and their new neighbors, just about to arrive, are the life blood of the California economy. And it is not permitted to criticize the richest state in the union and, depending on whether you include a cost-of-living index, either the sixth or the eleventh richest economy in the world, even though the difference between the two rankings is largely the ever-rising cost of real estate in this constantly booming and busting economy. We are supposed to love our good fortune, somehow, according to our leaders, whose main purpose is to produce a constant din of communal good fortune, when anyone who has lived here for any length of time realizes things are not, actually, getting much better. Perhaps jobs are easier to find than they were in the depths of the Great Recession. We're not in a drought this year. Marijuana is legal now, which is sending waves through the state's rural real estate market. Enforcement of federal environmental laws and regulations is relaxing, and in some cases the laws themselves are being extirpated like an endangered species, which is supposed to be good for jobs and the economy. Rents are rising, foreclosures keep on going on, and the only thing that can get homeowners out to local government meeting is the terror that its approval of a development project will lower their property values. Yet, despite these boons pulling us away from our slow, sleepy Western way of life toward authentically modern, LA consciousness, knowledge that we live in a state that has lost a million people in recent years, and not to notice that loss, is an uncomfortable and spooky.-- blj
California’s next megaflood would be worse than eight Hurricane Katrinas
By Eric Holthaus


Worse than the 1906 earthquake. Worse than eight Hurricane Katrinas. Worse than every wildfire in California history, combined. The world’s first trillion-dollar natural disaster.
A wintertime megaflood in California could turn out to be the worst natural disaster in U.S. history by far, and we are making it much more likely, according to an alarming study published this week in Nature Climate Change.
The odds are good that such a flood will happen in the next 40 years, the study says. By the end of the century, it’s a near certainty. (And then another one hits, and another — three such storms are possible by 2100). By juicing the atmosphere, extreme West Coast rainstorms will happen at five times their historical rate, if humanity continues on roughly a business-as-usual path, the new research predicts.
The study’s lead author, Daniel Swain, a climate scientist at the University of California, Los Angeles, and a lifelong Californian, says the best way to understand what we’re doing to California’s weather is to think of earthquakes.
“A major earthquake on the Hayward Fault in the San Francisco Bay Area or on the San Andreas Fault east of Los Angeles is an inevitability in the long run, and either event would likely be devastating,” Swain says. “Yet the big difference with the risk of a major flood event is that human activities are greatly increasing the likelihood of the physical event itself through the emission of greenhouse gases.”
Three years ago, much of the Pacific Northwest sat in stunned silence after reading Kathryn Schulz’s Pulitzer-winning description of “the really big one” — an unimaginably huge earthquake, a full-margin rupture of the Cascadia subduction zone. Within months of that article, Congress held hearings and proposed new funding to prepare.
California’s looming megaflood would likely be much worse.
In terms of sheer destruction, displacement of human life, re-ordering of society, a California megaflood would be without parallel in modern U.S. history. The state’s levees aren’t designed to attempt to hold back such a flood. The blow to the world’s sixth largest economy would send shockwaves throughout the world.
On his blog, Swain wrote: “Climate scientists are sometimes accused of being ‘alarmist,’ but I would argue that alarm is a reasonable human response.”
In 2011, the USGS assessed the modern-day implications of a flood like the one that happened in the winter of 1862 — currently the worst flood in California history. An unceasing onslaught of atmospheric rivers brought Los Angeles three years worth of rain, more than 36 inches, in a month and a half. Floodwaters turned California’s Central Valley into an inland sea, from Bakersfield to Redding. When it was all finished, the storms had destroyed one-third of the taxable land in California, and bankrupted the state.
Swain’s research considered the consequences of these megafloods on the state’s water management system and found the signs of catastrophe:
[S]uch events would be unprecedented in California’s modern era of extensive water infrastructure. Few of the dams, levees and canals that currently protect millions living in California’s flood plains and facilitate the movement of water from Sierra Nevada watersheds to coastal cities have been tested by a deluge as severe as the extraordinary 1861–1862 storm sequence—a repeat of which would probably lead to considerable loss of life and economic damages approaching a trillion dollars.
And, deep breaths, this isn’t the worst-case scenario. It is “plausible, perhaps inevitable”, according to the USGS, that a flood even worse than the 1862 disaster will occur again. The USGS called their scenario the “ARkStorm” — a thousand-year megastorm — and made a stark warning: “The hazards associated with such extreme winter storms have not tested modern infrastructure nor the preparedness of the emergency management community.”
For California, it looks like the worst of climate change is just getting started.
California Legislative Analyst's Office
California Losing Residents Via Domestic Migration

Brian Uhler, Justin Garosi
...For many years, more people have been leaving California for other states than have been moving here. ... On net, the state lost 1 million residents to domestic migration—about 2.5 percent of its total population. These population losses are low in historical terms.