New rainfall totals show that no person alive has experienced a three-week period in the Bay Area as wet as these past 21 days. The last time it happened, Abraham Lincoln was president.

From Dec. 26 to Jan. 15, 17 inches of rain fell in downtown San Francisco. That’s the second-wettest three-week period at any time in San Francisco’s recorded history since daily records began in 1849 during the Gold Rush. And it’s more than five times the city’s historical average of 3.1 inches over the same time.

The only three-week period that was wetter in San Francisco — often used as the benchmark for Bay Area weather because it has the oldest records — came during the Civil War when a drowning 23.01 inches fell from Jan. 5 to Jan. 25, 1862, during a landmark winter that became known as “The Great Flood of 1862.”

“The rainfall numbers over the past three weeks just kept adding up. They became a blur,” said Jan Null, a meteorologist with Golden Gate Weather Services in Half Moon Bay, who compiled the totals. “We had a strong jet stream that was bringing in storms, one after another. It was hard along the way to separate the individual storms.”

So much rain fell since Christmas in Northern California that some cities, including Oakland, Stockton, Modesto and Livermore, already have reached their yearly average rainfall totals. In other words, if it didn’t rain another drop until October, they would still have a normal precipitation year.

The parade of soaking storms, which have caused flooding in the Central Valley, Salinas Valley and Santa Cruz Mountains, along with power outages, mudslides and at least 20 deaths statewide, left the Sierra Nevada with a statewide snowpack 251% of normal on Tuesday.

Light rain is expected Wednesday night, but otherwise forecasts call for dry conditions for much of the rest of January. River levels now are dropping.

“We’ve gotten so much water and so much snow,” said Daniel Swain, a climate scientist at UCLA. “It’s going to help us dry out and dig out heading into late January. It’s really good news because it takes off the trajectory toward worsening flooding.”

For a sense of how much worse it has been, consider the winter of 1861-62.

Between November 1861 and January 1862, it rained so much that the Central Valley became a vast inland sea, 30 feet deep, for 300 miles. Leland Stanford, who had been elected governor, took a rowboat through the streets of Sacramento to reach his inauguration.

Warm storms on a massive snowpack that winter caused immense flooding, wiping farms, mills, bridges and in some case whole towns off the map. An estimated 4,000 people died, roughly 1% of California’s population at the time, and more than the death toll in the 1906 San Francisco Earthquake.

Now, California has large dams and reservoirs that limit flooding in wet years. There also are thousands of miles of levees and pumps, weirs and other flood control projects that were not in place in the 1860s.

And despite the recent wet weeks, Northern California is nowhere near the final yearly rainfall total of 1861-62. San Francisco on Tuesday had 21.75 inches of rain since Oct. 1. That total would have to more than double in the coming months to reach the 49.27 inches that fell in 1861-62, or the 47.19 inches that fell in the second-wettest year in history, 1997-98.

Weather experts have become increasingly concerned that if another massive winter like 1861-62 hit — and tree rings and other historical records show they have occurred roughly every 100 to 200 years — millions of people could be trapped by floods, freeways could be shut for weeks, and the damage could reach into the hundreds of billions of dollars.

A study last summer by scientists at UCLA found that the chances of such a series of huge storms, while still remote, have roughly doubled due to climate change. Climate change has warmed ocean waters, allowing more moisture to be absorbed in atmospheric river storms.

Swain, a co-author of that study, said that climate change is already increasing the amount of moisture in such storms by about 5%, and that will climb as temperatures continue to warm.

Very wet winters are nothing new in California. Since July 1, San Francisco has had the fifth most rainfall on record. But all four of the wetter periods were in the 1800s.

“California has always had big storms like this,” said Park Williams, an associate professor of geography at UCLA, whose research has shown that droughts and wildfires are becoming more severe due to warming. “Climate change can make them more intense. But we might have had a year this wet whether or not we had climate change. And 1862 proves that.”

The 220 passengers and all crew members were unharmed, according to the spokesperson. As of 11 a.m., the passengers were currently being rescued and being returned to the nearby Pleasanton station. The train was not derailed in the incident.

Service may be impacted throughout the day as crews work to clear the tracks before they can make determinations on what to do with the impacted train.

For this point in the water year — which starts in October — the totals are around twice the average at many Bay Area spots. November was drier than normal, and December brought about double the average rainfall.

The totals below are from Dec. 1 to Jan. 16 at National Weather Service stations.

The site of the greatest reading, Uvas Canyon, is at 1,100 feet elevation near the Casa Loma fire station, about 2 miles east of Loma Prieta.

To the south, Mining Ridge, at 3,288 feet elevation in Big Sur, has recorded 84.16 inches from Dec. 1 to this week.

Read more: 35 key figures that sum up the atmospheric river blitz

National Weather Service predictions showed calm, chilly air Tuesday in the Bay Area. Highs in the mid-50s were consistent throughout, with San Jose, San Francisco and Oakland each expected to top out at 55 degrees. Overnight temperatures could drop to the mid-30s, however, accompanied by calm winds and a dry, rainless night.

Those showers should diminish by Thursday, however, as temperatures were forecast to drop to highs in the low 50s before slowly rising to the high 50s by Saturday, giving the Bay Area its first completely dry weekend of 2023.

Engineers and prisoners alike risked life and limb as they built the two-lane highway into the majestic coastal cliffs of the Santa Lucia mountains. The 18-year project eventually connected San Luis Obispo to Carmel via the seaside, where the geology makes the road inherently susceptible to landslides. The 1937 grand opening even included a symbolic blasting of a boulder, which the governor cleared from the road with a bulldozer. It was the first of many to come.

Now, incessant storms are causing landslide trouble on Highway 1. Again.

Multiple problems

A 45-mile section of Highway 1 extending from Deetjen’s Big Sur Inn in Monterey County to Ragged Point in San Obispo County is currently closed due to landslides, with no estimate on when it will reopen. And residents, businesses and Caltrans crews along the Big Sur coast are bracing for more geological activity as winter storms continue rolling in.

Closures like this along the Big Sur coast are not uncommon. Residents and businesses aren’t surprised when they are temporarily cut off from the world. Caltrans engineers know they must move mountains off the road. Repeatedly.

But nobody gives up on California’s crown jewel highway, which is recognized by the U.S. Department of Transportation as a National Scenic Byway. Laborers, who seem to be working continuously to repair damage and rebuild sections after landslides, are lauded as heroes, and locals host celebrations for reopenings.

‘Challenges and rewards’

“A ribbon of highway on the edge of the continent presents challenges — and rewards,” said Kevin Drabinski, the Caltrans District 5 public information officer.

“We make these closures for the safety of the traveling public. It’s an international travel destination, and, just as important, it’s home to communities and businesses. So we try and do the best we can to keep it open,” he said.

Landslides come with the geology of the area. “It’s old ocean floor stuff that makes up a lot of the California coast that’s been accreted or pushed up on the continent, so it’s been faulted and folded and distorted and weakened,” said Gary Griggs, a professor of Earth Sciences at UC Santa Cruz.

Landslides on Highway 1 usually happen during storms, when water hits soil, making the soil heavy, lubricated and more fluid. Gravity sends chunks of mobilized mountainside plunging from steep, sweeping cliffsides into the crashing waves below — or onto the highway.

Caltrans prepares for winter storms in the fall. Crews inspect and clean out culverts, which Drabinski describes as the “unsung heroes of Highway 1.” Some workers even rappel from the cliffs with picks and other tools in hand to dislodge loose rocks. Worker safety is always a priority.

The goal is to make the cliffs as stable as possible going into the winter. “We put special focus on areas that are downslope of the Dolan fire burn scar,” said Drabinski. Previously burned areas are especially prone to slides when the rains start.

The precarious road has been closed due to landslides dozens of times since it first opened in 1937. The road closed 55 times between 1937 and 2001, according to a 2001 report.

The worst event in that period was a 963-foot-high landslide in 1983 near Julia Pfeiffer Burns State Park. The New York Times reported that it took 13 months, 30 bulldozers, 7,700 pounds of explosives, and $7.8 million to clear it, and one bulldozer operator lost his life in the process. When it reopened, residents threw a party with bands, balloons and a 52-foot-long carrot cake, according to the New York Times.

More recent winters have produced some of the worst — and most costly — landslides in the road’s history. Each time, Caltrans has been prepared and quick to respond.

In February 2017 a landslide displaced a damaged column of the Pfeiffer Canyon Bridge. Crews demolished and completely replaced the bridge with a new $21.7 million bridge designed to reduce its susceptibility to landslides. The new bridge was completed in October 2017 after an effort to design and construct a new bridge quickly that Jim Shivers, a Caltrans spokesperson, described in a 2017 article as ”remarkable.”

But the road remained closed to the south — in May that same year, a landslide had buried the highway near Mud Creek, just north of the Big Sur Lookout. The massive event, described in the national news by Executive Director of the Big Sur Chamber of Commerce Stan Russell, as “the mother of all landslides,” buried a quarter-mile section of the highway 40 feet deep. The road reopened 14 months — and $54 million — later.

In January 2021, the road itself collapsed into the sea leaving a steep and terrifying void where the mountainside used to be. But Caltrans took advantage of subsequent dry weather and restored the road faster than anticipated. It reopened in April 2021, nearly two months ahead of schedule and only three months after the initial event.

The repeated cycle of damage and repair seems tedious, but there aren’t many other options for a coastal highway built into the mountainside.

“I think it’s always going to be this Band-Aid approach,” said Griggs. “We fix it up and wait for the next one, but it’s a place where that’s the only choice.”

“We do put a lot of resources into maintaining Highway 1 on the Big Sur coast,” said Drabinski. “It’s prompted out of service to the residents and businesses of the Big Sur community and to the travelers who return there because of its natural wonder.”

Normally response crews can approach Paul’s Slide, one of the current trouble spots, from the south. “When the highway is open, we just shoot up from Cambria, go right up the road past Ragged Point and deliver the goods,” he said. But with the southern closure, everything has to detour and enter from the north.

Drabinski said it’s “certainly likely” that conditions will worsen if the rains continue.

Caltrans said in the press release that they “will continue to take advantage of any break in inclement weather to assess road conditions and provide access as long as the conditions are favorable for public travel.”

When Highway 1 does open again, “the best way to view the scenic wonders of the Monterey coast is to park one’s car frequently and to enjoy the views at leisure,” according to a 1937 article in the Monterey Peninsula Herald. “Fortunately the great slides that have taken place during construction have resulted in scores of wide parking spaces, nearly all of them at points where the vistas are the most remarkable.”

Sacramento’s streets were flooded. In fact, much of California was. A 300-mile-long lake was created in the Central Valley from near Bakersfield to Red Bluff. At least 4,000 people were killed.

It was the largest flood in the recorded history of California, Nevada and Oregon, dumping 10 feet of water on this state over a 43-day period.

The Great Flood of 1862 followed a 20-year drought.

Gov. Gavin Newsom seems, in every other sentence, to blame the intensity of our current storms — or any drought or wildfire — on climate change. We’re getting drier and wetter and the cycles are becoming more frequent, he and experts warn.

OK, I’m no climatologist. But I do read history. And you can acknowledge history without being a climate denier. Burning fossil fuel has warmed the planet and appears to have mucked up our climate. But we’d still suffer terrible droughts and disastrous storms even if all the energy we used was carbon free.

Cycles of drought and flooding have been the California way — nature’s way — for eons.

Times columnist Gustavo Arellano recently wrote about the Great Flood of 1938.

“California has lots of extremes. We’ve always had more wet years and drier years than any part of the country,” Jay Lund, vice director of the UC Davis Center for Watershed Sciences, once told me. “Every year we’re managing for drought and for floods, and we always will.”

Yes, and we’ve got lots of catching up to do on flood management with or without climate change.

But the state has added little to its once-prized water system since approval of Gov. Pat Brown’s then-controversial California Water Project in 1960.

One failure is we’re not capturing and storing nearly as much floodwater as we should. The primary example is in the Sacramento-San Joaquin River Delta, the source of drinking water for 27 million Californians and irrigation for 3 million acres.

Ideally, we’d be grabbing big pools of nature’s gift and storing it for use in dry years. Instead, it escapes through San Francisco Bay and flows into the ocean.

One immediate reason we’re capturing less water than we could is a regulation agreed to by the former Trump administration.

Under it, the “first flush” of each season’s major storm is reserved for the bay. For two weeks, state and federal pumps at the southern end of the Delta have been permitted to pump at only about half capacity.

The main reason is to protect endangered fish. Aggressive pumping reverses San Joaquin River flow, sucking endangered tiny smelt and little salmon into the pumps or mouths of large predator fish. But fish aside, the reverse flows draw in salt water from the bay. And that gets pumped south into Southern California reservoirs.

“That’s why we’re so focused on the Delta tunnel. It’s going to allow us to pump large amounts of water during big winter storms without an environmental impact,” says Wade Crowfoot, secretary of the state Natural Resources Agency.

Fresher Sacramento River water from the north Delta would be siphoned into a 45-mile-long, 39-foot-wide tunnel ending near the southbound aqueducts. If it had been in place, Crowfoot estimates that an additional 131,000 acre-feet of floodwater could have been captured during the current storm as of late last week.

But small Delta communities, local farmers and environmentalists worry that if the tunnel existed, water grabbers — meaning San Joaquin agriculture and L.A. — wouldn’t just be taking stormwater. They’d also be seizing water during dry summers and droughts, leaving the Delta saltier.

All that must be negotiated and litigated. If it’s ever built, the $16-billion project probably couldn’t be operational until at least 2040.

There also needs to be more storage room for floodwater. There’s a perpetual cry for additional costly dams. But we’re already dammed to the brim. There are nearly 1,500 dams in California. Practically every good site has been used.

But one sensible dam project is noncontroversial and headed for construction. It’s Sites in Colusa County, an off-stream reservoir that would hold 1.5 million acre-feet of water siphoned off the nearby Sacramento River. Construction on the $4.5-billion project could begin in 2025.

Some existing dams, including San Luis in Merced County and Los Vaqueros in Contra Costa County, probably will be expanded.

But the future of storage is underground in depleted aquifers. That’s a major focus of state and local governments.

Meanwhile, even with climate change, Newsom didn’t need to row a skiff to his recent second inauguration at the Capitol. He was driven to the outdoor ceremony in a big SUV as storm clouds briefly parted.

George Skelton is a Los Angeles Times columnist.

The county, along with much of the state, will remain under a flood watch through the evening Monday as saturated soils struggle to absorb storm runoff. Urban and small stream flooding is expected, according to the National Weather Service.

On Monday morning, flooded Highway 37 remained closed in Novato between Highway 101 and Atherton Avenue — the second lengthy closure since the rains began. Caltrans announced that as of 11 a.m. the eastbound lanes and one westbound lane had reopened, but that the rightmost westbound lane would remain closed with no projection yet on when it would reopen.

Monday is expected to remain partly sunny and with sun forecast all day Tuesday. A rainy afternoon Wednesday will clear out overnight before a sunny end to the week and weekend, according to the NWS.

Wednesday’s weather system “will be the final rainmaker for a while and thankfully this will move through the area quickly,” according to the agency’s forecast. “High pressure then builds over the region allowing things to dry out into at least early next week, if not beyond.”

There will be colder overnight temperatures in the next week, increasing risk of frost, according to the NWS.

Approximately 75 Pacific Gas and Electric Co. customers had no power on Monday morning, according to the utility’s outage map.

Several roads in West Marin remained closed Monday according to the county’s website, including Fairfax-Bolinas Road, which has been closed since Jan. 4.

In a statement Monday, the White House said the president will visit with first responders, state and local officials, and communities impacted by the recent extreme weather; survey recovery efforts; and assess what additional federal aid is needed.

California has been hit by nine atmospheric rivers since Christmas. Across the state, the storms have killed at least 20 people and caused at least $1 billion in damage.

Biden on Saturday declared that a major disaster exists in California and ordered federal aid to supplement state, tribal and local recovery efforts in the areas affected by severe winter storms, flooding, landslides and mudslides beginning on Dec. 27 and continuing.

Funding is now available to residents of Santa Cruz, Sacramento and Merced counties.

In a separate statement, the White House said assistance can include grants for temporary housing and home repairs, low-cost loans to cover uninsured property losses and other programs to help people and businesses recover from the effects of the disaster.

Check back for updates.

After weeks of rain, one last storm Sunday night had residents waking up to more floods and mudslides Monday morning.

Ryan Orosco found himself in 3-foot-deep floodwaters at his mobile home along Bixler Road in Bryon shortly after daybreak. He carried his wife and young son separately out of the home. Thanks to the home standing on a raised platform, none of the water managed to make it inside. However, 3 to 4 inches of water seeped inside his parents’ home next door.

“It’s really stressful to deal with it,” said Orosco, 35. “It just baffles me how much water came down.”

In Berkeley, a mudslide slammed into Marjorie Cruz’s home on Middlefield Road about 6:30 a.m. Authorities issued mandatory evacuation orders to more than a half-dozen properties in the area.

“It’s completely shocking – I don’t have words to describe what I’m looking at,” she said. “Who expects to wake up in the morning and see an entire hillside in their dining room?”

For now, however, evacuees and weathered residents across Northern California can refocus on clearing the mounds of dirt and detritus thrust into their homes and draining lingering rainwater as the National Weather Service lifts flood advisories and the Federal Emergency Management Agency and the state’s Office of Emergency Services deploy aid.

Scroll down for photos, then click here to read the rest of our coverage.

With dry weather forecast for most of the next week, here’s a tally of the storms’ stunning impact, so far, by the numbers:

9: Number of atmospheric river storms to hit California in the past three weeks.

20: Number of confirmed fatalities, as of Monday, from California storms since Christmas.12: Number of confirmed fatalities in California wildfires in 2021 and 2022.

41: Number of California’s 58 counties under federal emergency declaration.3: Number under major disaster declaration (Santa Cruz, Merced, Sacramento).

24.5 trillion: Estimated gallons of water that fell on California from Dec. 26 to Jan. 11.16: Number of times that amount of water could fill California’s largest reservoir, Shasta Lake.

17: Inches of rain measured in downtown San Francisco since Dec. 26.3: Historical average in inches of rain that falls in downtown San Francisco over same time.

3: Number of times the San Lorenzo River hit major flood stage since Dec. 27, prompting evacuations and flooding neighborhoods.

40: Size of the hole, in feet, torn in the historic Capitola Wharf during the storms.

62: Miles of Highway 1 in Big Sur that remained closed Monday due to landslides.

1.19 million: Gallons of water flowing every second through the Sacramento-San Joaquin River Delta on Friday.1.12 million: Gallons flowing every second down the Columbia River, the largest river on the West Coast, on Friday.54,712: Gallons flowing every second through the Delta on Dec. 1.

27: Feet of snow that have fallen at the UC snow lab at Donner Summit since Nov. 1.12: Feet of snow that fell on average from 1991-2020 at the lab over the same time.

247: Percent of historic average for statewide Sierra Nevada snowpack, on Monday.106: Percent of historic average for statewide Sierra Nevada snowpack on Dec. 1.

1,046: Bay Area lightning strikes on Jan. 14-15, including one that hit the Golden Gate Bridge.

500+: Number of landslides statewide caused by storms, since New Year’s Eve, according to the California Geological Survey.

34 million: Number of Californians — 90% of state population — under flood watch Monday Jan. 9.

143: Percent of normal rainfall since Oct. 1 in San Jose through Monday afternoon.196: Percent in San Francisco.219: Percent in Los Angeles.229: Percent in Oakland.424: Percent in Bishop in the Eastern Sierra.

100: Percent full for all seven reservoirs operated by Marin Municipal Water District.86: Percent full for all seven reservoirs operated by East Bay MUD.56: Percent full for all 10 reservoirs operated by the Santa Clara Valley Water District (Anderson, the largest, had to be drained for earthquake repairs).

33: Percent full for Lexington Reservoir near Los Gatos on Dec. 1.100: Percent full for Lexington Reservoir on Monday.

46: Percent on Thursday of California in “severe drought,” according to the U.S. Drought Monitor.85: Percent on Dec. 1 of California in “severe drought.”

0: Number of major storms forecast for the next week.