Why the ‘Big One’ Could Be Something Other Than an Earthquake

Drought and wildfire are the horrors dominating headlines this time of year. But California also faces the threat of another kind of calamity, one that could affect the whole state and cause more economic damage than a big San Andreas Fault earthquake.

New research by climate scientists has found that the risk of a monthlong superstorm, one that would pummel both Northern and Southern California with rain and snow in astounding quantities, is rising rapidly because of human-caused global warming. The chances each year of one occurring are already around one in 50, the study estimates. And the likelihood keeps growing the more we pump greenhouse gases into the atmosphere.

Warmer air holds more moisture, which means atmospheric rivers — the storms that sweep in from the Pacific and are sometimes called “Pineapple Express” events — can carry bigger payloads of precipitation.

California has been struck by giant atmospheric-river-fueled storms before. A particularly devastating one in 1861-62 transformed the Central Valley into an inland sea, and Sacramento was flooded so severely that Gov. Leland Stanford had to take a rowboat to his inaugural events in January 1862, according to the Sacramento History Museum. The State Legislature also temporarily moved to San Francisco.

The state has since dammed up its rivers and built bypasses to whisk floodwaters away from population centers. If that 19th-century storm hit today, all of this infrastructure would make it less likely to cause destruction. Still, the state is also far more developed — with bigger cities, more valuable farms and businesses, and many more people — which means the consequences could still be great.

If there’s good news to report in any of this, it’s that plenty of planners and policymakers are aware of the risks. As I wrote in The New York Times on Friday, the Department of Water Resources is planning to use the new scientific findings to update the state’s flood plans. With the help of supercomputers, they will map out in detail how all of that precipitation will flow through waterways and over land.

California is also working to strengthen levees in urban areas of the Sacramento and San Joaquin Valleys to provide protection against 200-year storms, or those with a 0.5 percent chance of occurring in any year.

As I found while reporting this interactive story, however, there’s another side to all of these preparations, which is that they’ve turned flood risk into something many Californians never think about.

On one level, that’s progress: Most of us have better things to do each day than worry about nature’s wrath. But there are also perils to not thinking you live in a danger zone. You might ignore evacuation orders, downplay storm forecasts, decline flood insurance.

“When the government is involved with these levees, most homeowners trust that we’re doing the right thing, and that it’s safe for them to put their life savings in a home,” Ricardo Pineda, a retired engineer for the state, told me as we toured Sacramento’s flood-management works recently.

“They love to walk their dogs on the levee,” Pineda said. But “are they prepared for the economic consequences of New Orleans-type flooding?”

In Lathrop, near Stockton, the River Islands planned community sits in an area on the San Joaquin River that flooded terribly during a 1997 storm. The developer built extra-wide levees, without using government funds, to protect the charming homes and tidy streets.

Susan Dell’Osso, president of River Islands Development, told me that many of her buyers were from the Bay Area and asked tough questions about schools and life in the Central Valley.

“They never ask questions about flooding,” Dell’Osso said. She tries to educate them about it, she said. But “they don’t even realize, I think, that there’s a risk.”

If you read one story, make it this

Would-be candidates, donors and activists are already busily plotting what a race to succeed Nancy Pelosi would look like — albeit almost entirely in secret.

What we’re eating

Taco recipes for the most delicious (and easy) summer party.

Where we’re traveling

Today’s tip comes from Jack Flanders, who lives in Arlington, Texas. Jack recommends Big Bear:

“With a beautiful lake and mountains, lots of places to hike, fish and plenty of water activities, also lots of live music and good restaurants. And you never know who you might see having a meal or strolling through the village. Can’t beat Big Bear.”

Tell us about your favorite places to visit in California. Email your suggestions to CAtoday@nytimes.com. We’ll be sharing more in upcoming editions of the newsletter.

And before you go, some good news

In June, an image of a crumbling sky blue structure with wood-trimmed windows was featured in an online magazine article on abandoned homesteads in the heart of the Mojave Desert. The house was once the home of Melody Gutierrez, now a reporter at The Los Angeles Times.

Gutierrez recently wrote about growing up on five acres in the desert, catching iguanas and rattlesnakes. In 1990, her parents moved her and her two siblings into a 714-square-foot house in Wonder Valley, just east of Twentynine Palms, to try to secure a safer and more affordable life.

Gutierrez and her siblings walked a half-mile to a bus stop to go to school. Her family carved their names into concrete they poured on the front patio. They took short showers because there wasn’t always money to fill the water tank perched on the roof.

But after seven years, they moved away. And Gutierrez didn’t ever return to where she had grown up — until last year.

When Gutierrez visited the sky blue home again, she found her old Barbie among the debris. She spotted a sign her dad had painted and recognized the blinds he had put up. It conjured emotions she hadn’t been expecting.

Childhood homes, especially those people live in between the ages of 5 and 12, tend to have an especially strong pull, with adults wanting to see them again, Jerry Burger, a retired Santa Clara University psychology professor, told Gutierrez.

“It seems to be those are key years,” he said. “For many people their identity is tied up with that place, with that time.”

Read more in The Los Angeles Times.

Thanks for reading. We’ll be back tomorrow.

P.S. Here’s today’s Mini Crossword, and a clue: Blended mush (5 letters).