Counterintuitive claim: Slower snowmelt in a warming world

From the NATIONAL CENTER FOR ATMOSPHERIC RESEARCH/UNIVERSITY CORPORATION FOR ATMOSPHERIC RESEARCH and the “eh, it’s a model projection” department, comes this claim. So, if it melts earlier, but then melts more slowly, it would seem to cancel out. I’m sure though somebody will find a crisis in this somewhere.


Slower snowmelt in a warming world

When snowpack melts earlier, it also melts more slowly, new study finds

As the world warms, mountain snowpack will not only melt earlier, it will also melt more slowly, according to a new study by scientists at the National Center for Atmospheric Research (NCAR).

The counterintuitive finding, published today in the journal Nature Climate Change, could have widespread implications for water supplies, ecosystem health, and flood risk.

“When snowmelt shifts earlier in the year, the snow is no longer melting under the high sun angles of late spring and early summer,” said NCAR postdoctoral researcher Keith Musselman, lead author of the paper. “The Sun just isn’t providing enough energy at that time of year to drive high snowmelt rates.”

The study was funded by the National Science Foundation, NCAR’s sponsor.

The findings could explain recent research that suggests the average streamflow in watersheds encompassing snowy mountains may decline as the climate warms — even if the total amount of precipitation in the watershed remains unchanged. That’s because the snowmelt rate can directly affect streamflow. When snowpack melts more slowly, the resulting water lingers in the soil, giving plants more opportunity to take up the moisture. Water absorbed by plants is water that doesn’t make it into the stream, potentially reducing flows.

Musselman first became interested in how snowmelt rates might change in the future when he was doing research in the Sierra Nevada. He noticed that shallower, lower-elevation snowpack melted earlier and more slowly than thicker, higher-elevation snowpack. The snow at cooler, higher elevations tended to stick around until early summer — when the Sun was relatively high in the sky and the days had grown longer — so when it finally started to melt, the melt was rapid.

Musselman wondered if the same phenomenon would unfold in a future climate, when warmer temperatures are expected to transform higher-elevation snowpack into something that looks much more like today’s lower-elevation snowpack. If so, the result would be more snow melting slowly and less snow melting quickly.

To investigate the question, Musselman first confirmed what he’d noticed in the Sierra by analyzing a decade’s worth of snowpack observations from 979 stations in the United States and Canada. He and his co-authors — NCAR scientists Martyn Clark, Changhai Liu, Kyoko Ikeda, and Roy Rasmussen — then simulated snowpack over the same decade using the NCAR-based Weather Research and Forecasting (WRF) model.

Once they determined that the output from WRF tracked with the observations, they used simulations from the model to investigate how snowmelt rates might change in North America around the end of the century if climate change continues unabated.

“We found a decrease in the total volume of meltwater — which makes sense given that we expect there to be less snow overall in the future,” Musselman said. “But even with this decrease, we found an increase in the amount of water produced at low melt rates and, on the flip side, a decrease in the amount of water produced at high melt rates.”

While the study did not investigate the range of implications that could come from the findings, Musselman said the impacts could be far-reaching. For example, a reduction in high melt rates could mean fewer spring floods, which could lower the risk of infrastructure damage but also negatively affect riparian ecosystems. Changes in the timing and amount of snowmelt runoff could also cause warmer stream temperatures, which would affect trout and other fish species, and the expected decrease in streamflow could cause shortages in urban water supplies.

“We hope this study motivates scientists from many other disciplines to dig into our research so we can better understand the vast implications of this projected shift in hydrologic patterns,” Musselman said.

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130 thoughts on “Counterintuitive claim: Slower snowmelt in a warming world

    • Does this Muscleman guy ever go look at real snow? Sometimes, it sublimes, y’know. Sometimes, aliens just steal it.
      Oh, yeah – is he aware that around 7,000 years ago, there weren’t any glaciers at all in the European Alps? And – oh, golly, Miss Molly! — we’re still here! Holy cow! I’ll bet that will give him the vapors!

      • Sara, maybe some, but mostly not. Here is the quote:
        “Once they determined that the output from WRF tracked with the observations, they used simulations from the model to investigate how snowmelt rates might change in North America around the end of the century if climate change continues unabated.”
        And, “tracked” what does that mean? It can track low, right on, or high. Or it can track for a few months or years then go amiss. Tracked within 10%, 100%, 200%? At all those observed stations?
        Now that the model “tracks” these observed data fro the database, let’s extend it to all of North America almost a hundred years from now using a simulation model. What could possibly go wrong.
        Finally, the “perpetual” drought in California turning to massive rain and snow should indicate the level of uncertainty in their predictions through the end of the century.

      • Yes, Leonard, and I have a friend who is a Forest Service firefighter in California. His response to the whole business of ‘surprise! end of drought!’ was that the older Forest Service workers knew the drought would end this year or the next, but they were ignored because their knowledge of drought cycles doesn’t fit the hysterics.
        They were right. The ‘expuurrts’ were wrong. Surprise! Heavy storms sweep California!

      • It would seem to me that, intuitive or counterintuitive wouldn’t care either way, if a warming world meant slower snow melt with an earlier melt season then that melt water would be more inclined to replenish groundwater rather than cause flooding and erosion which in turn would be beneficial rather than detrimental to the biosphere

      • Quoting article:

        “When [mountain] snowmelt shifts earlier in the year, the snow is no longer melting under the high sun angles of late spring and early summer,” said NCAR postdoctoral researcher Keith Musselman, lead author of the paper. “The Sun just isn’t providing enough energy at that time of year to drive high snowmelt rates.”

        That is one amazing statement by NCAR postdoctoral researcher Keith Musselman.
        So, iffen the winter snowfall starts melting in early spring due to air temperature increases ….. it will slow up or quit melting in late spring and early summer when the air temperatures are really hot.
        But iffen the winter snowfall didn’t start melting because the early spring air temperature remained cool/cold ….. that winter snowfall won’t begin melting until late spring and early summer after the air temperatures have increased to being hot.

      • Samuel, I don’t see your problem. If the snow has melted slowly before late spring it is not there to melt quickly when the sun gets on it (or where it was until it melted). I don’t know whether this happens, but it seems plausible.

      • it is not there to melt quickly when the sun gets on it

        Seaice1, ……. getta clue, ……. solar irradiance (Sunshine) does not directly cause snow or snowpack to melt …….. primarily because the snow or snowpack reflects the solar irradiance.

  1. counterintuitive finding

    1. Counter reality
    Deceptively incorrect use of term “counterintuitive”
    2. “finding” — not.
    To be a “finding,” there must be something (outside one’s imagination) “found.”
    In a word: “junk.”

    • It does make sense that snow that melts earlier will melt more slowly. It’s also true that when all the snow melts quickly, there will be flooding. This sounds like basic hydrology.
      The paper doesn’t sound wrong. It just sounds like something that engineers have understood for a long time. In what way is this paper new information? What am I missing?

      • Unlike “Kenji’s” accurate comment below (https://wattsupwiththat.com/2017/02/27/counterintuitive-claim-slower-snowmelt-in-a-warming-world/#comment-2438234 ), the paper simply assumes that slower snowmelt happens due to a “warming world.” There is NO data to support the paper’s cause-effect assertion. Thus, it is not a real thing Musselman has “observed,” i.e., not a gee whiz, counterintuitive, but real “finding.” It is his mere speculation (based on grossly misinterpreting what YOU and “Kenji” know to be hydrological fact).
        There has been no increased rainfall event frequency (no matter how many times Mike Maguire keeps trying to tell us so — I have posted cites refuting his assertions at least 3 times on WUWT) over the past several decades. Thus, “Kenji” put a “sarc” after that statement about > rainfall in his comment.
        So:
        1. IF there were actually significant “global warming” happening; AND
        2. IF there were a corresponding increase in rainfall events (it would be expected to, but, it has not happened….. not warming enough, so…..);
        3. AND IF that paper were asserting the above (it is not), THEN, the paper’s “findings” about snowmelt would be worth looking into.
        Thank you, cBob for so diligently, faithfully, correcting my potential errors here on WUWT.

      • It just sounds like something that engineers have understood for a long time. In what way is this paper new information? What am I missing?

        That scientist are not engineers.

      • commiebob: Maybe this?
        “We hope this study motivates scientists from many other disciplines to dig into our research so we can better understand the vast implications of this projected shift in hydrologic patterns,” Musselman said.
        Send more money please?

      • Janice Moore February 27, 2017 at 12:50 pm
        … To be a “finding,” there must be something (outside one’s imagination) “found.”

        I was faithfully and diligently agreeing with you and elaborating on what you said. The paper finds nothing that isn’t already well known.
        I have seen many papers with extensive literature reviews that manage to miss the fact that the paper’s content is already covered in undergraduate engineering textbooks. If these scientists got out more and associated with people outside their very narrow specialties they might avoid that kind of thing. You don’t have to be a hydrologist to know that hydrology deals with snow melt or that snow melt often causes flooding in North Dakota.

  2. dig into our research
    Uh, heh. — No, thanks.
    Bobbes, Gozer, Kika, and Chubby will do that analsysis for us.

    (youtube)
    Conclusion (of Bobbes, et al.): This stuff STINKS. (but, boy, did we have fun!)
    #(:))

    • Thanks Janice, I see I am not the only one who has a dog that enjoys horse poop. I quit taking my dog to the barn because he always came back to the truck a nice green color, and got to ride in the bed. Somehow I think he was thinking “this is as good as it gets for a dog”. Sorry if this seems off topic. We were talking about excrement, right?

      • Somehow I think he was thinking “this is as good as it gets for a dog”” unless there’s a dead skunk to roll around on. 🙂
        I live in CA. Some years ago, a dead grey whale washed up on the beach, just south of San Francisco. My brother Mike and I went to take a look. We could smell the carcass while still a mile away.
        At the site, two men with a tractor and large fletching knives were carving it up, and hauling away the huge slices. The whale was big enough that only the men’s heads were visible when they stepped into it.
        The stench close up was almost blinding. Several people were there with their dogs. Every single dog was straining at the end of the leash trying to get to the whale.