Claim: Sierra Nevada snowpack not likely to recover from drought until 2019

From the UNIVERSITY OF CALIFORNIA – LOS ANGELES and the “a 31 year dataset is spliced onto another enough for any conclusion” department comes this claim:


Northern Sierra Nevada ski resorts, like Squaw Valley Alpine Meadows, have received several feet of snow in March 2016. Image: Squaw Valley resort

UCLA researchers’ new method could be useful for analyzing snowpack in other mountains

Even with this winter’s strong El Niño, the Sierra Nevada snowpack will likely take until 2019 to return to pre-drought levels, according to a new analysis led by UCLA hydrology researchers.

Additionally, they suggest their new method, which provided unprecedented detail and precision, could be useful in characterizing water in the snowpack in other mountains, including ranges in western North America, the Andes or the Himalayas. These areas currently have much less on-site monitoring than in the Sierra Nevada.

The study was published online today in The American Geophysical Union journal Geophysical Research Letters.

“With the consecutive years of ongoing drought, the Sierra Nevada snowpack’s total water volume is in deficit and our analysis shows it will to take a few years for a complete recovery, even if there are above-average precipitation years,” said the study’s principal investigator, Steve Margulis, professor of civil and environmental engineering at the UCLA Henry Samueli School of Engineering and Applied Science.

Much of California’s water comes from the when the Sierra Nevada snowpack melts. The winter of 2015 capped four consecutive years of drought that resulted in the largest cumulative drought deficit spanning the 65 years that have been examined. The water volume of the snowpack in 2015 was just 2.9 cubic kilometers, when a typical year is about 18.6 cubic kilometers.

“It is critical for regions like California, that rely on their regional snowpack for water supply, to understand the dynamics of the system,” Margulis said. “Our new tool could help not just California, but other regions, gain insight about their regional snowpack.”

The researchers created a dataset covering 31 years (from 1985 to 2015), using measurements from NASA Landsat satellites, which provide daily maps of the full Sierra Nevada snowpack that have about 10 times sharper resolution that previously available. While there are on-site sensors throughout the mountain range, they are typically in the middle elevations and do not provide a full, high-resolution picture of the entire range, particularly at higher elevations, Margulis said. The researchers combined their new dataset with other snow survey data, collected by the state’s Department of Water Resources, to extend the time series of range-wide snowpack volumes back 65 years to 1951.

Using the data, the researchers applied probabilistic modeling methods to make predictions of snowpack water availability. Accounting for the four-year snowpack deficit from the 2012-2015 drought, the researchers say it will likely take until 2019 to get back to pre-drought conditions.

“Our larger goal is to build a very detailed, continuous picture of the historical snowpack, diagnose the primary factors that cause it to vary, and then ultimately improve models for predicting how much water will be available from it,” Margulis said. “This unprecedented information can help policy makers make more informed decisions with regard to this critical resource, especially as climate change affects it.”



57 thoughts on “Claim: Sierra Nevada snowpack not likely to recover from drought until 2019

  1. Thirty one years of data? Should we hold our breath for another eighty plus so we can extract the most preliminary climate signals?

    • Oh, I think we can do better than that — provided always that we keep a keen eye on and close account of ENSO’s slopes and landings. Especially regarding start and end points.

    • 1. At least they START with real data, not model simulated guesses.
      2. 31 years of satellite imagery plus 65 years of snowpack measurements may be the best they can get.
      3. What they do with/to the data is another question and deserving of close scrutiny.

    • Or maybe not. We are into a negative PDO. Remember the last one and the CA droughts back then. We need to maintain what little perspective we can from what (little) we know.

    • Hmm,

      ““Our larger goal is to build a very detailed, continuous picture of the historical snowpack, diagnose the primary factors that cause it to vary, and then ultimately improve models for predicting how much water will be available from it,”

      Their goal seems appropriate. Let’s assume that water is important. Maybe its not, but lets not be skeptical of everything just because there is a post about it. So lets assume for the sake of argument that water is important. Maybe farmers need it, maybe people need to drink, maybe industry needs it. maybe power generation is effected

      So, you are a civil engineering professor. And you have a number of datasets to work with. You’ve got

      this one

      Thats your long series.

      But your long series has some sampling issues. So the question is can we improve the accuracy by
      using satellite data during and overlap period. Think of it as comparing two thermometers side by side

      Whoever wrote this

      ““a 31 year dataset is spliced onto another enough for any conclusion”

      Doesnt understand how you combine point series with satellite data. The ground based data is used as verification

      Margulis first paper proved out his method

      using data going back to 1985 he then presented results

      A newly developed state-of-the-art snow water equivalent (SWE) reanalysis dataset over the Sierra Nevada (United States) based on the assimilation of remotely sensed fractional snow-covered area data over the Landsat 5–8 record (1985–2015) is presented. The method (fully Bayesian), resolution (daily and 90 m), temporal extent (31 years), and accuracy provide a unique dataset for investigating snow processes. The verified dataset (based on a comparison with over 9000 station years of in situ data) exhibited mean and root-mean-square errors less than 3 and 13 cm, respectively, and correlation greater than 0.95 compared with in situ SWE observations. The reanalysis dataset was used to characterize the peak SWE climatology to provide a basic accounting of the stored snowpack water in the Sierra Nevada over the last 31 years. The pixel-wise peak SWE volume over the domain was found to be 20.0 km3 on average with a range of 4.0–40.6 km3. The ongoing drought in California contains the two lowest snowpack years (water years 2014 and 2015) and three of the four driest years over the examined record. It was found that the basin-average peak SWE, while underestimating the total water storage in snowpack over the year, accurately captures the interannual variability in stored snowpack water. However, the results showed that the assumption that 1 April SWE is representative of the peak SWE can lead to significant underestimation of basin-average peak SWE both on an average (21% across all basins) and on an interannual basis (up to 98% across all basin years).

      And now he has extended it

      So funny

      “”“a 31 year dataset is spliced onto another enough for any conclusion”

      1. There was no splicing
      2. 3 minutes on google shows you he was validating against ground truth.

      • A good assessment. However, I have a problem with the sentence “the Sierra Nevada snowpack’s total water volume is in deficit and our analysis shows it will to take a few years for a complete recovery.” The Sierra Nevada snowpack thaws almost completely every year. I don’t understand what “deficit” they mean.

        It boils down to a question, how well can they predict the total snow deposit for a year. Given today’s state of models, they simply can’t. Not unless they employ some sorcery.

  2. These people are in a giant make work scheme for otherwise unemployable ‘scientists’. You don’t have to be a genius to work out that some amount of above normal snowfall will have to happen in the next 3 years to make up for 4 years of deficit.

    I am reeling at their certainty that 3 years will do it.

    • The really silly part is that substantially ALL the snowpack melts each year. It isn’t glacier country. So ANY above average precipitation year ought to be “recovery”…

      Northern California has had above average precipitation this year.

      Just sayin’….

      You smell that?…. gotta go….

  3. Beware. Australia listened to such experts in the last drought and ended up buying desal plants for coastal cities with high average rainfall…which promptly soared well above average as soon as the drought ended around 2010.

    Do I need to say that these largely or totally unused plants are costing well over half a million a day (each) as our dams brim? The construction of Melbourne’s desal was delayed by…flood!

    Btw, Sydney’s driest year was 1888 and the driest year for the continent was likely 1902. Driest decade was the 1930s. It all passed – it just didn’t seem likely to pass when it was happening (never does). Don’t know about the US west, but when things finally get wet in Oz they can get so chaotically wet (thinking 1950 here!) that “new tools” for prediction are likely to make their inventors look like old tools.

    • Having been advised to put in the desalination plants by the climate scientists instead of far cheaper dams there is the problem of providing lots of electricity to them, if they are ever required to be run, with limited intermittent production from renewable energy projects that are being constructed based on advice by the same mob! Seriously, having been very poorly advised initially would you use the same advisors ever again, only seems to happen in the phony world of “cllmate science.

      • Not to put too fine a point on it:

        They believe in magic. They think capitalism is magic. They think science is magic. They think technology is magic.

        But it ain’t, see?

  4. Whew! They managed to squeeze “climate change” in there right at the end. I was worried they might have forgotten. Close one.

    • They also got in the word “unprecedented”, which is a good thing, because it would have been unprecedented to have a climate change anything (apparently including information) that was not unprecedented.

  5. Only just remembered to get in the words “climate change” in the last line. They’re going to lose their grant money if they don’t get it in a few more times than that.

  6. To me, the ‘tell’ is the claim that being above average precipitation is still a drought.

    We had well above average this year. Above average is NOT A DROUGHT.

    If you define it the way they want, then about 75% of the time, you have a drought by definition. Even when it is flooding. As has already happened a few times now.

    I’m getting tired of writting “Yet Another Flooding Drought” stories…

    • Welcome to California, the land of permanent drought, permanent gridlock and one government employee per household to make excuses.

      Oh wait. You moved out. Nevermind. Seems you aren’t the only one.

  7. Sierra Nevada snowpack’s total water volume is in deficit and our analysis shows it will to take a few years
    Man made metric…..Sierra Nevada does not have a memory

    • Precisely what I was thinking. It appears they are conflating “water deficit” with “snowpack.” A water deficit is based on some human-defined average precipitation. The mountains’ snowpack, on the other hand, can easily go above-average with a single bad snowstorm.

      • The deficit is based on man made consumption above the levels of the average of the past 1,000 years. They have been sucking the aquifers dry now for a while.

      • It’s the same as taxes. One can never have ‘enough’ water or tax money because one can always use more than whatever they get in the first place. California’s droughts only appear to be getting more severe because there is an ever increasing number of people using the limited amount of water we get each year. Even if precipitation was “normal” for 50 years in a row it wouldn’t be enough.

  8. Paywalled, but read the abstract. One part makes no sense, the other is mathmatically invalid. Landsat can show snowpack extent, but neither depth nor water content (heavy v. light snow matters). Those things have to be ground sampled, and Landsat cannot increase the sample resolution. Makes no sense.
    The probability models are simple Monte Carlo simulations. That is methodologically suspect, as weather and climate both show persistence/autocorrelation and are NOT random year to year. That is true for SoCal drought now in its 4th year, teleconnected to the phase of the PDO and AMO as shown by USGS papers back in 2007.
    Unimproved data run through an inappropriate probability model to generate a press release ignoring both issues. Par for the warmunist course.

  9. … their new method, which provided unprecedented detail and precision, …

    ‘detail’ and ‘precision’ do not imply accuracy. Here’s a cute example.

    So, if you are playing soccer and you always hit the left goal post instead of scoring, then you are not accurate, but you are precise! link

    We’ll see what Mother Nature thinks about their predictions.

    • Bob, what they are saying is the old method….the one they told us to believe for decades…..was garbage

    • Exactly CB. Here in Australia we have a habit if “drowning” out the likes of our biggest alarmists in Flannery and his climate commission.
      It was the “expert” advice he gave to government that our dams would never fill. That resulted in the billions wasted on desalination plants around the country instead of new dams.

  10. Well, that’s not so long. Consider how long it took to recover from the MWP?

    “Scientists believe that the glaciers found in California today were formed about 700 years ago during the Little Ice Age (Guyton, 1998).”

    See: Glaciers of the Sierra Nevada: Past, Present, and Future. Emily Schultz. Indiana University,d.cGc

  11. As long as the greens run Californias water system, it will be something of a crisis situation. There is no free market for water, but the greens tend to sue for environmental interests, like the delta smelt, over the water rights of the farmers and cities.As no one is actually paying for water at anything resembling a market rate, especially the greens, real conservation is not that possible.

    • I’m surprised someone hasn’t gone down and given the delta smelt a coup de gras to end their, and everybody else’s pain. Of course if this happened, there would be something else. It’s not the species the marxbrothers are concerned about.

      I can’t understand why authorities are so hamstrung. Build a 30 foot electric fence around the construction sites and build the dams that are needed, including impounding flood runoff waters from the major cities – pipe it to a water containment structure and also use it to recharge aquifers. Why are we letting non elected people haters run the show. Also put an end to the dumbing down education that enables these parasites to exploit the population.

  12. It would be interesting to see if the observations on the ground, i.e. the measurements taken by a person going outside to measure the snowfall that has actually happened, tally with the observations from the satellite for the same location.


  13. More science by press release. The abstract says nothing definitive about the snow pack at the end of winter 2016, but the paper cites real measurements showing 85% of normal snow pack on 4/1/16 (the traditional end of the snow season). Other sources say the snowpack was 97% of normal. The paper involves a probabilistic model predicting the likelihood of a deficit in 2016 based on the status of El Nino!. The paper was submitted on 3/2/16, so the modeling was done before the 2016 snow season ended (Some changes may have been made in revision submitted 5/11/16.) Even worse, the paper calculated projected cumulative snowpack deficits. The four-year drought has an impact of this year’s ground water and reservoirs (some are filled to capacity), but this year’s snowpack is independent of last year’s snowpack.

    If you believed that extreme 2015/16 El Nino produced a larger than normal snowpack in California this year, you have been misled. It was merely average.

    FWIW, Mammoth Mountain Ski Area is remaining open until July 4, 2016 and currently claims 60 inches of snow at the summit and a high of 60 degF.

    The paper is freely available here:

    Analysis of the Sierra Nevada (USA) snowpack using a new spatially distributed snow reanalysis data set, in combination with longer term in situ data, indicates that water year 2015 was a truly extreme (dry) year. The range-wide peak snow volume was characterized by a return period of over 600 years (95% confidence interval between 100 and 4400 years) having a strong elevational gradient with a return period at lower elevations over an order of magnitude larger than those at higher elevations. The 2015 conditions, occurring on top of three previous drought years, led to an accumulated (multiyear) snowpack deficit of ~ −22 km3, the highest over the 65 years analyzed. Early estimates based on 1 April snow course data indicate that the snowpack drought deficit will not be overcome in 2016, despite historically strong El Niño conditions. Results based on a probabilistic Monte Carlo simulation show that recovery from the snowpack drought will likely take about 4 years.

    • I can’t lay my hands on it right now, but Scientific American published an article maybe 18 months ago regarding a California mega-drought that lasted more than 50 years that occurred around 1100 CE. On a slightly different note, does anyone but me have a concern over the robustness of an analysis that gives a 95% confidence interval return period of between 100 and 4400 years given 65 (?) years of data.

  14. With La Niña looking like it’s going get started in short order, isn’t the drought in California likely to resume? I am under the impression that drought conditions are more likely in La Niña years. Or am I mistaken?

  15. “the researchers say it will likely take until 2019 to get back to pre-drought conditions.”

    That means it must be safe to re-enact the Donner Party’s trek through the Sierra Nevada mountains this winter. Who’s with me?

  16. The only reason for any concern and for regarding this as a “critical resource” is because humans have voluntarily decided to live in and make permanent domiciles in an area that causes them to depend on snow pack melt. Prior to that it wasn’t an issue.

  17. The silliness of California’s drought. My friend was down in SoCal last summer. He was at a restaurant with nice green grass out front. He was told that because of the drought, they couldn’t give him a glass of water for free. They could either charge him $0.50 or sell him bottled water. After eating he went to the bathroom, and flushed a 5gallon/flush toilet, and washed his hands with about another 2 pints of water.

  18. Would think NOAA would be embarrassed to reveal how bad their computer models fail to predict temperature. When one looks at the wide range of predictions from the various models, it is sad. What a waste of taxpayers dollars. The chart proves the models are useless and NOAA lacks sufficient technology and understanding of the behavior to predict anything. They should just admit that the computer models are useless and the lack of understanding the fundamentals that drive the temperature, and stop making costly alarmist claims.

  19. I don’t know what this report means, however, I do think there is more to a rebound to a drought then just one “normal” year. I thromp thru the South Sierra and the Sierra Eastside quite a lot. Even though the precipitation was normal this year many springs and seasonal streams are not running. The springs are ones I’ve never seen fail before in 30 years. I assume there is a “deficit” in the soil moisture and fracture system water accumulations built up over the previous few years that wasn’t replenished this year. There is a lot of new “bug kill” too in places I didn’t see last year. I try to stay positive about that thinking the survivors (and there are always some) will be all that more healthy with the forests thinned. Now if people (PCT hikers too) can just not keep lighting and burning my favorite places with their damn campfires.

  20. “…The researchers created a dataset covering 31 years (from 1985 to 2015), using measurements from NASA Landsat satellites, which provide daily maps of the full Sierra Nevada snowpack that have about 10 times sharper resolution that previously available…”

    This 10x resolution has been just sitting there waiting to be used for 3 decades?

  21. So they prefer satellite data when it comes to snowpack instead of surface-based sensors which don’t offer the same coverage. Why don’t we do the same with temperature? Hmmmm…

  22. I am amazed seeing this kind of “academic” research results when the cross checking with common sense. First of all, the rainfall last year, even with the El Nino effect, is not sure really above average. From the data of the California Data Exchange Center, the rainfall in the northern Sierra Nevada is indeed 120% of the average, but the central part is ~100%, and the southern is only 91%, let alone other central and southern areas of California which are also below average:

    Secondly, after the full melting down of the snowpack on Sierra Nevada, the overall (statewide?) reservoir storage is 87% of the average as of today, and please be reminded that this figure is after a so called severe drought for three years and also 8 and half months of daily usage, there will be another 3 and half months to go before the next water year:

    My question is: why then such a panic about drought? In Australia, 87% in this situation could be a very sweet figure.

  23. I see a problem for California. A La Nina is likely this coming fall/winter. In the likely event the multidecadal oscillation(s) continue their making of the recent global warming pause for another 15 years, this likely coming La Nina is likely to be a double-dip one, which means it will probably repeat in the fall/winter of 2017/2018.

    Another problem for California is that the multidecadal bump centered around 2004-2005 and the warming caused by increased greenhouse gases (even though I see that as 40-50% of IPCC expectations) are disproportionately warming the Arctic because of a regional positive feedback there (ice cover change carrying over from one year to the next more than in the Antarctic, and more land with variable snow coverage). This seems to be shifting northern hemisphere weather patterns slightly more northward, which means a little less winter precipitation on SoCal.

    And SoCal is in poor shape to handle a population increase while its water supply will likely run quite low through 2018 and probably be a little less than it was through the remainder of this century.

  24. Lessee now. La Nina is predicted tor the coming winter and that implies that the snow pack will be less than the past year.

  25. The problem is not that enough water in generated. The problem is that there are too many intended uses of that water? It is really a matter of Man’s out of control population.

    • Choice of location has everything to do with too many people for the water available.

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