Future Flooding

Future Flooding title=
Bullards Bar Dam in the Sierra Nevada foothills north of Sacramento spills water during 2017 atmospheric river storms. (Photo: California Dept of Water Resources)
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By Harrison Tasoff, UC Santa Barbara

California is on track to get drier over the coming decades. But that doesn’t mean the golden state’s water woes come only from too little rain. In a new study, researchers at UC Santa Barbara and UCLA warn that flooding potential associated with extreme precipitation events is set to sharply increase.

These storms are anticipated to become more intense overall, but a smaller fraction of their precipitation will fall as snow. This means a smaller snowpack in the Sierra Nevada, a critical part of the state’s water storage. The twofold impact of increased precipitation and reduced snowfall, the researchers said, could lead to unprecedented flooding that could overwhelm the current capacity of many California reservoirs. The study was recently published in Geophysical Research Letters.

“Climate warming is contributing to the acceleration of the global hydrologic cycle with increasing emissions of heat-trapping gases,” said lead author Xingying Huang, a postdoctoral climate researcher at UC Santa Barbara’s Bren School of Environmental Science & Management and Earth Research Institute. “Evidence and projection show precipitation extremes will be more extreme.”

This is due to the strengthening of a phenomenon Californians know all too well: Atmospheric river storms. Aptly named, atmospheric rivers are corridors of water vapor in the sky. They stretch hundreds of miles wide and can carry volumes of water comparable to the flow at the mouth of the Mississippi River.

Atmospheric rivers can pour heavy rain over short periods of time, on the order of a few hours to a couple days. These rivers in the sky are essential to California’s water supply, contributing up to half of the state’s water. Extreme activity is heavily associated with flooding.

The new study predicts that precipitation during heavy atmospheric river storms will become more extreme. Runoff from the storms could increase by an average of 50% by the 2070s, as projected in a high-emission scenario, and could double or more in elevations above 5,000 feet, where decreases in snowfall will be the greatest.

Huang — along with UCSB professor Samantha Stevenson and Alex Hall, the director of the Center for Climate Science at UCLA — leveraged data from previous studies and historical rain and snowpack data to simulate atmospheric river events under future climate warming scenarios.

“Extreme atmospheric rivers like the ones we analyzed have the potential to cause a lot of flooding as the precipitation pours quickly,” Huang said. While more rain for California may sound good, the infrastructure that manages water resources and flood control may not be prepared for the magnitude of runoff the scientists project.


The extra water provided by these events could be a boon — especially for the much drier eastern Sierra Nevada slopes — if it can be captured and stored. However, that is not a simple task. The extra water supplied during more intense atmospheric rivers could also lead to more flash floods, debris flows and landslides.

Nearly all rivers draining from the Sierra Nevada mountain watersheds are impounded by reservoirs, which serve to store water for the drier months of the year. “The capacity of those reservoirs could be exceeded by river water volumes in a way that is unprecedented,” Huang said. The study suggests that preparing infrastructure for storing water from heavy precipitation will become extremely important for later use during drought periods.

According to the California Department of Water Resources, the state has experienced more than 30 major flood events in the past 60 years, resulting in hundreds of lives lost and billions of dollars in disaster claims. Damage from more extreme storms has the potential to be worse than that of hurricanes typically seen on the East Coast. 

Reduced snowfall in the Sierra Nevadas is the other half of the “double whammy” effect the study predicts. Less snow means less streamflow supply during dry periods. “It matters whether precipitation falls as snow — which stays stored away in the mountains until it melts in the spring — or as rain, which flows into our reservoirs and flood control channels right away,” Huang says.

Snowpack acts as a natural reservoir, which melts slowly and releases water little by little. Snow both stores water late into the year and prevents runoff from overwhelming natural waterways and human infrastructure. Heavy snow loss in the future could further jeopardize the future of California’s water supply.

The researchers plan to build on the results of this study, further investigating potential flood control and water resource management strategies. “I am also interested in researching the potential ecologic and economic impacts, and adaptation strategies,” Huang said. She and Stevenson hope their research will inform risk assessments of future climate extremes, which can help California communities, industries and public agencies prepare for extreme weather.


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m-cubed Sep 19, 2020 12:46 PM
Future Flooding

pfft this man-made stuff is nothing. recorded human history hasnt even been through an entire cycle of earth wobbling on its axis which takes 26,000 years and really throws things off weather-wise. modern humans have been brought to near extinction as recently as 80k years ago. some hypothesize that we had civilizations at that time and by the time we got things back together 10k years ago in iraq it wasnt a first, it was a recovery.

macpuzl Sep 19, 2020 01:18 PM
Future Flooding

Precession does not cause much change on insolation, and therefore has very little effect on climate. And if you're postulating such vaporous "civilizations", where is the archaeological evidence?

Nothing you're fantasizing about can explain the rate of change of our climate over the last two centuries except the human contribution to greenhouse gasses, especially carbon dioxide.


m-cubed Sep 19, 2020 01:24 PM
Future Flooding

quit putting words in my mouth. my opening sentence acknowledged the man-made aspect of it all.

macpuzl Sep 19, 2020 01:32 PM
Future Flooding

You really think so? Ws it in code?

sandy1 Sep 20, 2020 01:34 PM
Future Flooding

Did it say this ? 01101111 01101100 01100100 00100000 01100100 01110101 01110011 01110100 00100000 01110000 01110101 01100110 01100110 01101001 01101110 01100111 00100000 01100010 01101001 01110100 01100011 01101000 00100000

macpuzl Sep 20, 2020 06:03 PM
Future Flooding

It probably did, unless that's meant to be your signature.

kohn1 Sep 19, 2020 01:24 PM
Future Flooding

Oh good. Another study.

macpuzl Sep 19, 2020 01:30 PM
Future Flooding

Yes, better to remain ignorant. Studies are a waste of time when you can just make stuff up.

ChemicalSuperFreak Sep 19, 2020 02:56 PM
Future Flooding

KOHN1: I'm still waiting for the "big one" that the brainy CalTech seismologists claimed would hit California...TWENTY YEARS AGO....

doulie Sep 20, 2020 09:05 AM
Future Flooding

I accept these so-called climate change reports as much as I accept pollsters predictions preceding an election.

a-1600633591 Sep 20, 2020 01:26 PM
Future Flooding

2:56 pm and others - If you knew some science, you'd know that absolute limits like that are never specified, and instead expressed in terms of probability. That wouldn't fit your chosen narrative, however.

ChemicalSuperFreak Sep 20, 2020 07:16 PM
Future Flooding

@ 1:26 PM: When learning to solve the Schrödinger equation in quantum mechanics, the particle in a 1-dimensional box with boundary conditions in evoked. The PROBABLILITY of finding the particle at the boundaries, where the potential is infinite, or outside the box, is exactly zero. The boundaries are, in fact, ABSOLUTE LIMITS. If you new some science, you know that...

a-1600661267 Sep 20, 2020 09:07 PM
Future Flooding

7:16 pm - That's why there's no such thin as tunneling. Oh, wait...

a-1600661386 Sep 20, 2020 09:09 PM
Future Flooding

Aside from being a total non-sequitur.

ChemicalSuperFreak Sep 20, 2020 10:17 PM
Future Flooding

@ 9.:07 PM: "Oh, wait" is right. I defined an INFINITE potential well (read very carefully). You're now talking about a phenomenon (tunneling) where the particle has a non-zero probability of being outside a box---because the box is a FINITE potential well.

bumblebee Sep 22, 2020 10:25 AM
Future Flooding

Or just make stuff up and call it a study.

EastBeach Sep 19, 2020 03:06 PM
Future Flooding

Great research. The damage to Oroville Dam's spillways in 2017 comes to mind.

a-1600619952 Sep 20, 2020 09:39 AM
Future Flooding

The Oroville dam spillway fail was due to insufficient engineering and' had nothing to do with "climate change".

EastBeach Sep 21, 2020 11:35 AM
Future Flooding

9:39 AM - That's like saying a man was killed by a bullet and not thinking about the circumstances surrounding the event.

a-1600563039 Sep 19, 2020 05:50 PM
Future Flooding

The shady background of the climate denial movement, financed by big carbon and right-wing "think" tanks:


Bene Sep 19, 2020 07:10 PM
Future Flooding

Acknowledging human contribution to green house gases is nice academically, but at this point of little practical use. No matter what humans do now, how long would it take to turn things around to any significant degree and could it even be done? Also, interesting that the focus is always on burning of fossil fuels and the like, when the elephant in the room is overpopulation. Even if we went back to horse and buggies and crude campfires to cook dinner, the sheer volume of humans' campfires, breathing, and excreting is enough to keep our earth very unhappy. This will never be solved, however, because neither progressives nor conservatives would dare do anything about the real problem. Also found it amusing that during drought, the self righteous proudly show how they let trees and landscaping die. That, arguably, contributes more to climate change than green house gases. For one example, north Africa was a bread basket filled with beautiful trees until the Romans cut down all the trees, causing the climate to change --to desert-like. It has not and will not come back. Can we?

a-1600568866 Sep 19, 2020 07:27 PM
Future Flooding

Nice fatalistic attitude there. We're all gonna die eventually, might as well be now.

There are measures we can take, and now is the ideal time.

a-1600574565 Sep 19, 2020 09:02 PM
Future Flooding

"the self righteous proudly show how they let trees ... die" Done watering my fruit/food trees. All my gutters are piped to tree root beds and storage tanks. Can you show us examples of people "proud" to let trees die?

a-1600574677 Sep 19, 2020 09:04 PM
Future Flooding

Though I agree humans will not get it together enough to head off disaster and destruction. People in my neighborhood are having two and three kids! What the heck are they thinking? Oh well. I'll be gone. I tried and did my best. Enjoy. (Yes, I'm wholly pessimistic.)

a-1600574761 Sep 19, 2020 09:06 PM
Future Flooding

20 or 30 years ago was the ideal time. I feel very badly for those young now and am glad I'll be gone as it gets worse.

Bene Sep 19, 2020 09:30 PM
Future Flooding

You don't remember how the city was letting big trees die because didn't want to water? Need that water conserved for more people and density! You don't remember how the proud water savers were showing off brown lawns, pulling out dead trees they let die? Acting like a brown lawn and no trees made them get water saver points?
Okay, so you like to water your trees, great anecdotal data point of one. I have some anecdotal data points too: some potted coastal redwoods (yes can be kept in pots if pruned, wonderful oxygenators) and wanted to donate some to parks and my ecologically proud neighbors. All told me didn't want them because they require too much water. Me, I'd rather water trees than more people.

a-1600622349 Sep 20, 2020 10:19 AM
Future Flooding

Thanks Bene. At least you're showing some rational thought here in this desert of political correctness.

a-1600624204 Sep 20, 2020 10:50 AM
Future Flooding

And look at how the City of SB has turned the once green de la Guerra Plaza into a field of ...dirt. That shows how unattractive it is so they are now planning to pave it over! Some of the city's "environmentalists" are on the de la Guerra Plaza Revitalization Project. ("Revitalization" should be in quotes because it's killing the grass and growing concrete, complete with a silly "arcade" leading from the city employee parking lot.) All or most of this is out of hostility to the several homeless people who used to lie and sit on the grass in front of City Hall, something disagreeable to councilmembers and "planners".

PitMix Sep 21, 2020 07:50 AM
Future Flooding

Bene, we focus on fossil fuel burning because that is something we can change. The current human population is not. The Chinese took endless guff for their attempts to limit population. You can't think that anti-maskers would accept a limit on the number of fertilized eggs they can birth. But if you have a solution to overpopulation that everyone would accept, please enlighten us.

a-1600575935 Sep 19, 2020 09:25 PM
Future Flooding

Re-set buttons in the past were epidemics and wars - endless and repeated population thinning mechanisms. We simply now have to adapt to the law of unintended consequences having mitigated them both, and now are stuck with only more voluntary population controls.. China tried - and the verdict is still out on the full impacts of their one-child policies. Suggest academia does less hand-wringing and scolding, and instead research more accommodations and adaptation to the explosive global population growth that is now the 21st Century reality.

oops Sep 20, 2020 06:38 AM
Future Flooding

oh no! the sky is falling ...in @ 11 years if you believe Greta & AOC

sandy1 Sep 20, 2020 11:32 AM
Future Flooding

Next they'll claim there is endangered Steal head in the Atmospheric Rivers . lol

macpuzl Sep 20, 2020 05:16 PM
Future Flooding

Some people are truly clue-resistant.

sonny Sep 20, 2020 11:17 AM
Future Flooding

Sierra Nevada shouldn't have an s on the end.

rubaiyat Sep 20, 2020 11:31 AM
Future Flooding

Why did these scientists let us build LaEntrada knowing it would be underwater?

a-1600629291 Sep 20, 2020 12:14 PM
Future Flooding

You think the scientists had control over whether La Entrada got built?

a-1600633530 Sep 20, 2020 01:25 PM
Future Flooding

Ever hear of building sea walls? If/when ....but probably never. Long, long, long before the Industrial Revolution, "climate change" happened and impacted human civilization. We remarkably have adapted and survived, and yet it comes again relentlessly. World anthropology is a far better course of study than this current "climate model" tinkering.

PitMix Sep 21, 2020 07:46 AM
Future Flooding

1:25, coronavirus laughs at your puny human adaptations. How many humans have miserable lives currently? Start building those walls, Mr. Gorbachev.

macpuzl Sep 20, 2020 10:58 PM
Future Flooding

The facts are so overwhelmingly stacked against the climate science deniers and carbon lackeys that they now wander off into seismology, anthropology, and quantum mechanics in an attempt to deflect the conversation and continue spreading their FUD about AGW.

NostraChumash Sep 21, 2020 08:38 AM
Future Flooding

Where does the "Unsinkable" Titanic sit today?..
Built by engineers who swore to have all the answers..
The best minds of the time, & yet, consider the thousand corpses who would disagree.
Your greatest equations are nothing more than a childs best guess.

NostraChumash Sep 21, 2020 09:27 AM
Future Flooding

I wonder what possible response to my factual comment could have been found to be so offensive as to warrant deletion?..
See..the best minds of today can do no better.
Even rats know to abandon a sinking vessel.

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