Hydroclimatology and Solar Explorations

Climate & Weather Representations


The assertions first that the world is warming, and second that the warming world is causing high mountain snows to melt earlier every year, leading directly to reduced streamflows (the Early Spring meme), appear to be unsupported by any evidence.  It is true that over 3,000 scientific papers, as well as many media promotions, along with more than a few universities, NGOs, and state institutions, claim that the Early Spring is a grave and undeniable fact.  But all of that alarm can be swept aside, because it is repudiated by simple, direct, high-quality, continuous, and long-term streamflow records.

Streamflows are what the Early Spring meme is truly about.

  • No snow?  Then much less streamflow, coupled with more rapid aquifer depletions.
  • No streamflow?  Then accordingly, no water.
  • No water?  Say goodbye to conifers and fish, honeysuckle and lilacs, birds and bears, as well as industry, communities and irrigated agriculture.  Even say goodbye ultimately to agriculture that relies upon groundwater rather than surface water.

I realize that I exaggerate a bit, but their persistent narrative appears to reduce to those take – away messages.  On the other hand to me, the actual evidence suggests something different.  Consider the simple image below for Clear Creek outside of Golden, CO.  The horizontal (mostly red) “ridge” of the semi-3D contour plot represents the peak flows of that stream on a monthly averaged basis, for any given year.  January flows are represented by the bottom row and the top row is naturally December.  The columns represent each year, starting in this case in 1995. 

The ridge signifies that peak streamflows customarily occur in June, if not later.  The peak values for the Clear Creek case typically exceed 500 cubic feet per second (cfs).  This is quite impressive for such a narrow channel, but that is par for the central and steep eastern Rocky Mountains.  I visited this stream earlier in the year during a March blizzard.  It was spellbinding to see the ice-laden flows along that stream in Golden, Colorado.  I know that this observation itself is a supporting anecdote which challenges the Early Spring meme.  But I don’t need to rely on anecdotes, given that the data is so comprehensive.

Because of the mostly consistent snowfall and subsequent melting patterns, the peak flow month for Clear Creek is always June, with a few exceptions for dry years, where it doesn’t matter and for this year 2019 when the peak is actually reached later, in July.  In other words, there is no trend down towards an earlier month such as May for peak flow.  Also there is not a trend up towards a later peak flow month such as July.  Because there is no trend, and because the peak month is almost always June, any hydrologist would have to agree that in our jargon-filled world, the peak flow pattern is stationary.*

The featured animation at the very top of this post covers 7 different streams in a slightly different representation.  The colors define the magnitudes of flows for any given month.  The green colors represent the peak flows for any given year.  The values are still in CFS (cubic feet per second). In these frames, January is placed at the top row and December is placed at the bottom.  The streamflows shown are : Animas River near Farmington, NM; Otowi gage of Rio Grande, NM; Big Lost River, Idaho; Kern River near Onyx, CA; Big Thompson River near Loveland CO; Cache La Poudre River near Box Elder, CO;  and Lake Fork River, Utah.

Each frame is displayed as a still image later in this post.  The important point of the animation is to again single out the relative stationarity of the streams, each within their own region, over the satellite period.  Some happen to have peak flows in May, some as late as July, and some have no clear peak month.  I could show longer time frames for most of these samples but to squeeze that data together, I’ll take some time and make a new composite image for a later post.

Simply from a visual examination, one can easily determine that none of the streams, which are scattered across the western US (and associated with the most important watersheds including the Snake River, the Colorado River and the Rio Grande), are clearly trending towards later or earlier peak flow months.  Trust your eyes if you trust the data.  If you don’t trust my development of the data, the USGS resource [1] gives you everything needed to corroborate independently.  There is no trend for any of these streams.

And yet, over 3,000 peer-reviewed scientific papers apply pressure that we should not believe our own eyes.  Here is a Google Scholar report which links the 3,000 plus citations to the Barnett et al. paper which can be credited for getting this Early Spring snowball rolling:

Potential impacts of a warming climate on water availability in snow-dominated regions

TP Barnett, JC Adam, DP Lettenmaier – Nature, 2005 –

All currently available climate models predict a near-surface warming trend under the influence of rising levels of greenhouse gases in the atmosphere. In addition to the direct effects on climate—for example, on the frequency of heatwaves—this increase in surface temperatures has important consequences for the hydrological cycle, particularly in regions where water supply is currently dominated by melting snow or ice. In a warmer world, less winter precipitation falls as snow and the melting of winter snow occurs earlier in spring …

Cited by 3194 Related articles All 36 versions

To be clear, the Early Spring meme starts more or less with this paper by Barnett, Adam and Lettenmaier [2], which relies only upon inaccurate models and references to other papers and yet asserts with confidence that:

  • Greenhouse gases will cause “a greater frequency of warming”, and
  • “in a warmer world, less winter precipitation falls as snow and the melting of winter snow occurs earlier in Spring”. and
  • “Even without any changes in precipitation intensity, … these effects lead to a shift in peak river runoff to winter and early spring, away from summer and autumn when demand is highest.” and finally
  • “..the consequences of these hydrological changes for future water availability — predicted with high confidence and already diagnosed in some regions — are likely to be severe”

I’ve somewhat carefully scoured this critically influential paper, published nearly 15 years ago.  As I was originally taught by my graduate advisor Dr. Daniel Evans at the Hydrology and Water Resources Department at the University of Arizona, I like to read the abstract and conclusions first, followed by figures and tables, and then I actually survey the text, with an eye on the most pertinent references.  I note that no figures are provided to reinforce their confident assertions.  There is a figure that shows the obvious fact that streamflows often are associated with snowmelt.  There is another figure about the “Trade-off between firm hydropower and stream-flow requirements”, and finally there is an anecdotal and frightening before-and-after photo of a Peruvian glacier.

There are no other figures and there are no tables within this paper.  There is no supplemental material either. Accordingly, there is no data or information within the premier study which support any of the bullets above.   Perhaps there is supporting information in the references.  But already this is a red flag.  The conclusions of any paper MUST be directly included in the same paper and not by reference.  Any who disagree are welcome to comment or author their own blog post wherever.

I’m almost as lazy as the next scientist, but I can go an extra half mile to examine a sampling of the 3,000 + references which might support.  I start for context with an interesting precursor paper [3], coauthored by Dr. Danial Cayan, a researcher whom I’ve been communicating with over the past year or so.  Not to detour but I’ve also been preparing a post relating to that communication.  As shown in the following equivalent Google Scholar citation entry, the original work by Cayan et al. on the Early Spring never actually used that term.  Nor did it immerse the topic in fear.  Perhaps that’s why it hasn’t received as many citations as the Burnett et al paper.

Changes in the onset of spring in the western United States

DR Cayan, SA Kammerdiener… – Bulletin of the …, 2001 –

Fluctuations in spring climate in the western United States over the last 4–5 decades are described by examining changes in the blooming of plants and the timing of snowmelt–runoff pulses. The two measures of spring’s onset that are employed are the timing of first bloom of lilac and honeysuckle bushes from a long-term cooperative phenological network, and the timing of the first major pulse of snowmelt recorded from high-elevation streams. Both measures contain year-to-year fluctuations, with typical year-to-year fluctuations at a …

Cited by 995 Related articles All 26 versions

I like Dr. Cayan’s early work, including that paper as well as another which explores streamflow connections to ocean index drivers.  I favor Cayan et al’s Spring Onset paper because of its open-minded approach to a simple question:  Are the timing of snowmelts in the Rocky Mountains changing?  They include a survey of some evidence on the timing of honeysuckle and lilac flowering.  They (amazingly) follow with an exploration of connections of Rocky Mountain moisture to the Pacific Decadal Oscillation (PDO).  The similarities given the limited data his author team examined appear striking.  I’m including this image of their PDO comparison, followed by one I independently developed from a prior Early Spring post.  First here is Figure 4 from the Cayan et al. 2001 paper:

Next, here is a PDO vs the Animas River streamflow time series from a 2018 post of mine.  Clicking on this image will link you to the pdf file of greatest relevance within that post:

In my paper [4] which features the Animas River, I have gone further and found a more compelling relation directly to Solar Cycles.  But that only helps to corroborate in my view that the PDO itself is driven ultimately by the Sun.

Returning to this Early Spring notion, would you believe that the PDO connection of Cayan et al. cannot be found anywhere in the Barnett et al paper?  It’s true, and I encourage any interested reader to confirm on their own.    Perhaps that oversight is what allowed thousands of subsequently emotionally charged papers to flower on this topic.

Obviously there is neither room nor time to survey every one of the thousands of papers, and I don’t claim to have done that.  But I’ve profiled a few as promised.  Here are some brief synopses in a table.

Selected study title, reference, and year

Take-Away Messages

DECLINING MOUNTAIN SNOWPACK IN WESTERN NORTH AMERICA [5] 2005 “The West’s snow resources are already declining as the climate warms”
Changes in the Timing of Snowmelt and Streamflow in Colorado: A Response to Recent Warming. [6] 2010 “..strong, pervasive trends in snowmelt and streamflow timing, which have shifted toward earlier in the year by a median of 2-3 weeks over the 29-yr study”
Climate Change in Colorado. A Synthesis to Support Water Resources Management and Adaptation. 2nd Ed. [7] 2014 “The timing of snowmelt and peak runoff has shifted earlier in the spring by 1-4 weeks across Colorado’s river basins over the past 30 years..”
Confronting Climate Change in New Mexico. Action needed today to prepare the state for a hotter, drier future. [8] 2016 “New Mexico’s climate is getting hotter and drier, driven by regional and global warming trends. This means earlier springs, hotter summers, and less predictable winters”
Trends and Extremes in Northern Hemisphere Snow Characteristics. [9] 2016 “..the trend towards earlier spring snowmelt, particularly at high latitudes..”
Water and life from snow: A trillion dollar science question [10] 2017 “ changing due to global warming in worrisome ways” and “The snow that does fall is melting sooner, producing earlier stream runoff ..”
Collaboratively Modeling Reservoir Reoperation to Adapt to Earlier Snowmelt Runoff [11], 2020 (that’s right!) “..researchers demonstrate that under a warmer climate, earlier peak streamflow compromises reservoir storage”

Finally, in no particular order, I am including the individual frames of the featured animation at a broader scale for greater ease of examination:

Animas River near Farmington, NM;

Big Thompson River near Loveland CO;

Cache La Poudre River near Box Elder, CO;

Big Lost River, Idaho;

Lake Fork River, Utah;

Otowi gage of Rio Grande, NM; and

Kern River near Onyx, CA.  


The Early Spring assertion appears authoritative simply by virtue of thousands of peer reviewed papers and estimates of trillion dollar impacts.   The collective authors of the notion might believe that the Early Spring assertion is necessary for the greater good, regardless of how well they have explored its veracity or lack of.   The actual evidence demonstrates that the Early Spring is a false alarm.  That alarm can be easily countered, if any had the will, by simply starting from the reproducible streamflow records featured here, and persistently asking questions both in public and in private.   



[2] Barnett, T.P., Adam, J.C., and Lettenmaier, D.P.  2005.  Potential impacts of a warming climate on water availability in snow-dominated regions.  NATURE  Vol 438|17 November 2005|doi:10.1038/nature04141

[3] Cayan, D.R., Kammerdiener, S.A., Dettinger, M.D., Caprio, J.M., and Peterson, D.H.  2001.  Changes in the Onset of Spring in the Western United States.  Bulletin of the American Meteorological Society (BAMS).  October, 2001.   DOI: 10.1175/BAMS-86-1-39

[4] Wallace, M.G., 2019, Application of lagged correlations between solar cycles and hydrosphere components towards sub-decadal forecasts of streamflows in the Western US.   Hydrological Sciences Journal, Oxford UK  Volume 64 Issue 2.   doi: 10.1080/02626667.2019.

[5] Mote, P.W., Hamlet, A.F., Clark, M.P., and Lettenmaier, D.P.  2005.  DECLINING MOUNTAIN SNOWPACK IN WESTERN NORTH AMERICA.  Bulletin of the American Meteorological Society (BAMS).  January 2005.  DOI: 10.1175/BAMS-86-1-39

[6]  Clow, D. W. 2010. Changes in the timing of snowmelt and streamflow in Colorado: A response to recent warming. Journal of Climate 23(9): 2293-2306.

[7] Lukas, J.  Barsugli, J., Doesken, N., Rangwala, I., Wolter, K., with contributions by Alvarado, R., Arnold, J., Averyt, K., Bardsley, T., Basdekas, L., Brekke, L., Clow, D., Day, G., Decker, K., Deems, J., Dilling, L., Easley, T., Finnessy, T., Gangopadhyay, S., Gilmore, A., Gordon, E., Harding, B., Hoerling, M., Horn, B., Kaatz, L., Kuhn, E., Livneh, B., McNie, E., Melander, K., Miller, P., Molotch, N., Pielke Sr. R., Pineda, A., Prairie, A., Rasmussen, R., Ray, A., Ruiz, A., Ryan, W., Sanderson, J., Saunders, S., Smith, J., Steger, R., Stokes, M., Tellinghuisen, S., Waage, M., Wood, A.    2014. “Climate Change in Colorado.  A Synthesis to Support Water Resources Management and Adaptation.  2nd Ed.  August 2014.   A Report for the Colorado Water Conservation Board.  Western Water Assessment, Cooperative Institute for Research in Environmental Sciences (CIRES), University of Colorado Boulder”:

[8] Union of Concerned Scientists. Authors not listed (which is not acceptable for a science group)  2016.  Confronting Climate Change in New Mexico. Action needed today to prepare the state for a hotter, drier future.

[9] Kunkel, K.E., Robinson, D.A., Champion, S., Yin, Xungang, Estiflow, T., and Rankson, R.M.  2016.  Trends and Extremes in Northern Hemisphere Snow Characteristics.  Current Climate Change Reports.  (2016) 2:65-73 DOI 10.1007/s40641-016-0036-8

[10] Sturm, M., Goldstein, M.A., and Parr, C.  2017.  Water and life from snow: A trillion dollar science question.  AGU PUBLICATIONS  COMMENTARY.  Special Section:  Earth and Space Science is Essential for Society  doi:10.1002/2017/WR020840

[11] Sterle, K., Jose, L., Coors, S. Singletary, L., Pohll, G., and Rajagopal, S.  2020 (that’s right), Collaboratively Modeling Reservoir Reoperation to Adapt to Earlier Snowmelt Runoff.  Case Study (that’s right)  Journal of Water Resources Planning and Management.  ASCE.  146 (10: 05019021


*I think this is interesting because I already know that the overall flow patterns of all of the streams that I have examined, throughout the Rockies as well as the western US, as well as throughout the world, wherever I have looked, are “cyclo-stationary”.  There are many posts as well as my paper [4] which relate and support.  

Why the font is not consistent.  I don’t know, but I’ll continue to try to find the best WordPress theme that overcomes this inconsistency.  Any comments are always welcome.

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