January 19, 2023

The California Drought is Over. Definitively.

After over a month of torrential rain and massive mountain snow, the drought is over in California.

Yet with all the liquid bounty, some in the media and elsewhere don't want to give up on it, as noted in the NY Times headline below.

And the U.S Drought Monitor has severe drought over much of the state.

I believe the evidence for the end of California drought is quite overwhelming. But consider the facts found below and decide for yourself.

Reservoirs and Snowpack

Let us start with the most critical measure of drought...the total water storage in the reservoirs plus the water that will be available from the snowpack (see below).

It is now WAY above normal.  

In fact, the total water available right now is greater than normally available in April after months of additional precipitation.

The previous deficit in California reservoir water storage is now gone.  For example, consider the huge Lake Orville Reservoir in northern CA" during the past month it went from roughly 60% of normal to 106%!  Wow.

Current snowpack, a critical water source for late spring, summer, and fall?

It is now over 200% of normal for all major Sierra regions...and nearly 300% for the south Sierra area.  Good skiing as well.
Soil Moisture and Rivers

The state has experienced flooding and highly saturated conditons from all the rain.   As you might expect, the soil moisture values arecurrently  very, very high (see below from NOAA National Integrated Drought Information System, NIDIS).  Green is above normal.  Dark green indicates the top 1% wettest period on record for the date.

Rivers around California are generally very high, with many running above the 90th percentile (top 10% flows for this period).

And the Palmer Drought Severity Index, which considers current and past precipitation plus temperatures, indicates wet conditions over the state.  No drought.

Making Up For Several Years of Precipitation Deficit

An important aspect of the massive amount of recent precipitation is that it has erased a multi-year deficit in precipitation.  Consider San Francisco, where the observed cumulative precipitation for the past two years is shown by green (and climatological variation indicated by the brown line)

For most of the past two years, San Fran has been behind normal precipitation, but the recent torrent has pushed it above normal!

A similar situation for Los Angeles.

But What About Lake Mead/Lake Powell and Ground Water?

The media has been fixated on Lake Mead/Lake Powell, whose water levels are both well below normal; both are fed by the Colorado River, not the Sierra Nevada reservoirs/snowpack  (see Colorado watershed below).   The water in these lakes supports water needs in southern CA and Arizona and provides electricity from Hoover Dam.

It is true that the water levels in the critical storage lakes/reservoirs (Mead and Powell) are dropping (see a plot for Lake Mead below).

But this decline is not from changes in meteorology/climate, but from increased usage to support a growing population and water-intensive agriculture.  You can see this by looking at the long-term trend in Colorado River Basin snowpack and water flow into Lake Mead (below).

Dropping groundwater levels in California are a similar story, with the largest drops during the past 20 years in agricultural areas of the southern Central Valley (see below).  We are mining too much sub-surface water to be sustainable.

The Bottom Line:   Much of California is a relatively arid, with little long-term trend in precipitation.  There is a reason that that Spanish did not move northward into California for two centuries:  the place was too dry for agriculture. Only a massive reservoir and water transportation system made a heavily populated state possible.

Much of California goes through natural periods of above and below normal precipitation, and we have just gone through such a cycle, moving from a few years of dry condition to a very wet winter.   

The recent meteorological drought is now over.  But California needs better long-term planning and infrastructure to sustainabley support the current and future pooulation and a huge agriculural industry.

 Blaming climate change as the primary cause for current problems and recent "drought" leads to not dealing with the real problems.

Annoucement:  I will have a special online zoom session for my Patreon supporters this Saturday at 10 AM.


  1. Anyone who has read "Cadillac Desert" knows California and the Colorado River have both suffered from at least a century of questionable water management decisions.

  2. Cliff, could you comment on the figure illustrating that CA has not yet recovered from drought? I suspect that it depends greatly on how long a period you integrate prior precipitation over. I agree with you that the managed water reservoirs are not a good indicator given that water usage is such an important factor. But you speak to climate, averages and anomalies often and here I'm not that satisfied with your analysis. You could probably say much more.

  3. Are you saying the U S drought monitor is wrong?, It's even showing parts of western Wa abnormally dry as of today's update.

    1. At best the US drought monitor is slow to update. Which perhaps there is a case for being slow to update, since drought is generally a long term trend, and decisions about water management arguably shouldn't be made quickly.

      But sometimes it still seems obvious that a dry trend has been broken. For example, if you click the button to show last month's status, it shows western Washington was in moderate drought.

      That was after weeks of steady rain - roughly 6 inches recorded at SeaTac over the mid-November to mid-December period, which is average - and with above average snowpack in the mountains.

      Thus, in those conditions, the drought monitor was warning that in western Washington, "Fire danger increases, Possible dust storms, River flow is low."

  4. It ain't over til it's over. Where I live (Humboldt Bay area) we are over normal slightly but only halfway to average for the year. Things could still get dry but it's looking good.

  5. It ain't over for Lake Mead or Lake Powell. The water levels here have barely budged. You need to take a look at the whole of the west. One wet season is not a trend.

  6. The MSM will never, ever give up on their climate alarmism, there's just too much money and cognitive biases at stake for them to admit the truth. Just watch Al Gore and the other moneyed interests at Davos act out like hormonal teenagers at their predictions of doom. Utterly pathetic individuals, and dangerous to boot.
    "There is a reason that that Spanish did not move northward into California for two centuries: the place was too dry for agriculture." One of the first observations the European settlers made when they first traveled into CA was the almost complete absence of any indigenous tribes. There was a good reason for that absence.

    1. There were ~40 native nations and ~400K people pre-contact, which was ~1/3 of all the US. Too dry for agriculture, but benign for hunter/gatherer.

  7. (?) “One swallow does not make a summer, neither does one fine day; similarly one day or brief time of happiness does not make a person entirely happy.” ― Aristotle, The Nicomachean Ethics

  8. Fascinating. I've looked at the "drought monitor" maps since they were first published, and I've kept an eye on the source data being fed in for our little patch of the map (north end of the Cascades). USDA historically issues maps weekly; there's a bulletin with a link to an online version of the map. Very near here there's a USDA SNOTEL that's located almost precisely "on the beeline" ("as the crow flies") between my location (I report daily precipitation measurements) and Mt Baker Ski Area. I've lived here 49 years, and I have a good idea what's happening at all three points. As of today, this particular SNOTEL (center point) reports 52" snowpack when just four miles further (at roughly the same elevation) the snowpack is 103" (113" at the higher PanDome location). That's not a small difference, that's an immense difference, and I've noted this for years (decades). Knowing the local topography and actual conditions, I'll just say "siting matters." And as 'yardsticks' go, I don't rely on that map seriously.

  9. I'm not sure that the drought is over I think California needs to see a few more years of average or better precipitation to definitively end the drought. I say this because 7 of the last 10 years have been much drier than normal in California, there is mass tree die off/alot of forest fires because there have been more drier than average years than wetter than average years. One wet year 2017 did not stop this tree die off its clear the ecosystem needs a string of wet years. Cliffmass is right that California occasionally sees really dry years but normally these dry years are balanced out by wet years. I lived in California from 1986 to 2014 and I can't recall so many dry years in a row.

    1. personal anecdotes aside, your analysis is missing some mighty big contrary statistics regarding CA droughts -


      CA has experienced "Mega Droughts" for millenia, so comparing anything that's occured over the past 100+ years is a fool's errand.

  10. Impressive numbers, indeed. However, % of normal numbers and ensuing projections assume normal precipitation the remainder of the wet season. Should the spigot be turned off, those numbers will surely decrease, possibly so far as to be below normal - which has happened before.

  11. I love the em·bar·rass·ment of riches which the 1 and 1/3rd Kilometer grid spacing that the U.W. Atmospheric Sciences puts out. A lot of computer power is needed!

  12. I get my weather info from your blog and the U of W Atmospheric Sciences web site

  13. Much of the inflows to Mead the past few years have come at the expense of draining Powell. Might be better to show thin inflows to Powell.

  14. Al Gore approves of this comment.

  15. Juan Browne, proprietor of the YouTube Blancolirio aviation channel, gives a most interesting and informative update to the California water situation, including a flight in his small airplane over the watersheds that feed California's reservoirs.

    California Flood/Drought UPDATE! 21 Jan 2023

  16. C'mon. I really like this blog but to say the drought is over is just silly. It's about the aquifers, not the snow pack or precip totals. Anyone who has spent considerable time in the central valley or eastern deserts of CA can attest to this. While events like this can help mitigate short term drought conditions it does NOT refill those aquifers. That takes years. Maybe never if you account for the rate at which agriculture and desert developments remove water from the aquifers.

  17. Professor Mass , in this post you're saying that the california drought is over, and I don't really have an opinion on that.
    But when you go on to say that the current levels of lake mead are the result of consumption and not drought, it's pretty clear you're not correct.
    you offer a graph showing water input to lake mead as being relatively static over time, but you don't seem to care that the overall lake level of lake mead has been dropping. If the input of water into lake mead is similar, how do you explain the dropping levels - or the high level to being with.
    Lake mead is the downstream reservoir. The water it holds is primarily delivered via outflow from lake powell, via the glenn canyon dam. That outflow is managed for power generation, for flows related to wildlife (humpback chub, beach building, etc) and to move water to lake mead. The flow of water via the colorado river isn't natural or uncontrolled. The majority of water coming into lake mead is what we decided to put there, not natural flows.

    Lake power buffers water surplus and deficits for lake mead. Even in low-input water years the pool at lake powell can and is used to continue to deliver water to lake mead, drawing down its level in low years, building it up in high years.

    In the last 20 years, looking at the uncontrolled input into lake powell, 15 of those 20 years were lower than the historical average input, and much lower in most cases. We masked this shortage because of the large amount of water stored in the lake powell/lake mead system, but more than a decade and a half of below average input means reservoir levels dropped, and substantially.

    the water compacts that allocate the colorado were drawn up during what appears to be a relatively wet period compared to the history. As a result the river is over-committed. During wet years you didn't see this because we had plenty of water. During dry years you didn't see this because we had storage.

    None of this supports your conjecture in this post that "there is no drought because inputs to lake mead have remained stable".

  18. Cliff, this is what the U.S. drought monitor has to say:

    "The long-term drought continues across California, the Great Basin and parts of the Pacific Northwest. However, a barrage of atmospheric river events – streams of moisture in the atmosphere that transport water vapor from the tropics – has reduced the drought intensity over the past few weeks. In California, 1-category improvements were made along the Northern Coast, around the Delta and along the South Coast region. While precipitation over much of the state was over 300% of normal over the previous 2 weeks (2 to 12.5 inches, depending on location), deficits have been years in the making. While this last round of rain has helped return smaller reservoirs to the historical averages, many of the larger reservoirs still remain below the historical average for this time of year. Historically, long-term drought is interrupted by a period of abnormally wet weather. However, it’s too early to tell if the wet weather is enough to end the drought. Many other parts of the West also saw improvements to drought and abnormally dry areas. In Oregon, 1-category improvements were made to extreme (D3) and severe (D2) drought in the southeast and near Klamath County based on above-average snow water equivalent and improvements to long-term indicators such as 6- to 24-month precipitation and shallow groundwater. In Idaho, severe (D2) and moderate (D1) drought improved where precipitation deficits over the past 12 months and streamflows show improvement. In Utah, areas of D3 and D2 improved based on precipitation in excess of 300% of normal (3 to 10 inches, depending on location) over the last 30 days and its resulting effect on streamflows, soil moisture, and groundwater. Heavy precipitation helped erase areas of abnormal dryness in parts of Washington, Oregon, western Wyoming, western Colorado, Arizona and New Mexico. The only places in the West seeing an expansion of drought were Oregon and Colorado. In Oregon, D1 was introduced in the south Willamette Valley and central Oregon Cascades and D1 and D2 expanded in the north-central part of the state. These expansions were in response to below-normal water-year-to date precipitation on top of longer-term deficits and groundwater impacts."

    Can you comment there? This post feels like you just want to take down some climate alarmists (which I won't deny are often wrong), but aren't not really considering the question in detail. Evaluating long-term precipitation trends is non-trivial, details matter. Talk about them. You are a scientist, this is your strength,.

  19. The irony. The snake River water system is not low due to drought. Its because people hate rain (chose to live in places where its dry)

  20. water rights and crop selection are really whats hurting CA. It was beautiful to see the green hills and wild flowers in bloom surrounding SF this last week.


Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

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