Hot, Dry Conditions Take a Heavy Toll on Western U.S. Snowpack

By Tom Yulsman | February 4, 2018 1:19 pm
An animation of satellite images shows just how much thinner the snowpack in California's Sierra Nevada range is this year compared to the same time last year. (Images: NASA Worldview. Animation: Tom Yulsman)

An animation of satellite images shows just how much thinner the snowpack in California’s Sierra Nevada range is this year compared to the same time last year. (Images: NASA Worldview. Animation: Tom Yulsman)

Thanks especially to warm temperatures, plus a lack of precipitation, the snowpack in most of the Western United States is in bad shape right now — nowhere worse than in California’s Sierra Nevada range.

For all but the northern reaches of the region, snowpack stands at no more than about 50 percent of average, and in many places it’s much worse.

For California, snowpack as of today, Feb. 4, is at just 25 percent of normal.

Luckily, the state’s reservoirs are still brimming with water, thanks to last year’s copious rain and snowfall. This will provide a sizable cushion for the year ahead should warm temperatures and scant precipitation continue.

“There’s still a lot of the winter left,” says Frank Gehrke of California’s Department of Water Resources, quoted by the Sacramento Bee. “Anything can happen as we move through the rest of the season.”

Still, the comparison with last year couldn’t be more stark — as the animation of satellite images above dramatizes. Both images were collected by NASA’s Terra satellite as it passed over the Sierra Nevada range. An image taken on Jan. 29, 2017 shows an extensive blanket of snow, whereas one acquired on Feb. 3rd of this year shows shockingly less.

Colorado, where I live, also is in pretty bad shape, with snowpack at just 35 percent of average for Feb. 4. I mention this because snowmelt and runoff from our mountains supplies the lion’s share of the water for the Colorado River Basin.

Nearly 40 million Americans rely on the Colorado River system for drinking water and to support farming, recreation and other livelihoods.

Here’s what snowpack looks like throughout the West:


Those blue and green circles in the northern tier of the region — from Washington into Idaho and Montana, and down into Wyoming — are indicative of healthy snowpack. This part of the West may be benefiting from La Niña, a climatic phenomenon characterized by cooling in parts of the tropical Pacific, with impacts on weather patterns far afield.

La Niña tends to tip the odds in favor of wetter than average conditions in the northern reaches of the western United States. But many other factors influence weather patterns as well. So I don’t think it would be accurate to say anything stronger than this: What we’ve seen so far in that northern tier region is consistent with La Niña. (For more on how La Niña may be influencing our weather, see this excellent post at NOAA’s ENSO Blog.)

Meanwhile, all those red, orange and yellow circles paint a grim picture when it comes to snow.

Warm temperatures have been a bigger issue than lack of precipitation. California, for example, has received 70 percent of its average precipitation since the water year began on Oct. 1, yet snowpack is at just 25 percent. Similarly, while Colorado’s snowpack is at 35 percent of average, it has actually received 62 percent of its average precipitation.

Warm temperatures have been causing snowpack to melt, and for more precipitation than normal to fall as rain rather than snow.

California still has three months to catch up, and much of the rest of the West has even more than that. So let’s keep our fingers cross that the pattern changes soon.

  • Not_that_anyone_cares, but…

    sciencemag … 4 days ago … Every spring in the western United States, snow melt…off mountains, feeding rivers with surges of water that
    can cause disastrous floods. But warm weather isn’t the main culprit, a
    new study finds. Instead, dusty soil that sticks to snow can darken it …
    and accelerate its melting.

    • OWilson

      Just like 2 years ago when California’s “Historic Drought” ended, they will soon be breathlessly complaining about floods and mudslides.

      Meanwhile in the Northeast they are getting record snowfalls, Boston, Chicago, and of course, Buffalo :)

      Maybe out West they feel entitled to perfectly even weather, but Ma Nature doesn’t work that way! :)

      • Ed Norris

        Funny how the predictions that Gore made about New York Subway system flooding with higher storm-surges made possible by global warming were ignored by the denialsphere. And that climate scientists have long been predicting more dramatic extremes as a result of climate change as well.

        But among the willfully ignorant, it’s all just a conspiracy. One that the fish, birds, and fish are all in on. The pay must be really good. How can the rest of us get in on it?

        Oh, and you’re welcome, Wilson, for granting you the attention you so desperately crave. I breathlessly await your stupendously clever response. Which no doubt will demonstrate that intelligence has nothing to do with one’s ability to overcome cognitive bias.

        • OWilson

          See that caption above, “Join the discussion”?

          All alternate viewpoints are always welcome in a free society.

          That’s the way truth eventually emerges over dogma!

          Ad hominem attacks, however, and appeals to authority, add nothing to a discussion.

          That sort of thing finds it’s best home in religion, or North Korea!

          Have a nice day!

          (You too, Mikey!) :)

          • Mike Richardson

            “Ad hominem attacks, however, and appeals to authority, add nothing of value to a discussion.” – – OWilson

            “You are an idiot and a waste of time!”. — OWilson

            “..some high level influential folks are saying…” – – OWilson

            Preach on brother, or is it comrade? 😉

          • OWilson

            Count the times when a serious discussion, is lowered to the Swamp, by folks like you and your trolling pals.

            The funny part is how you snowflakes get your hissy prissy panties in a knot if I occasionally respond in kind to trolls!

            The above thread is a good example!

            Hava a nice day!

          • Mike Richardson

            Yeah, terrible me for pointing out what an enormous hypocrite you are. :)

            “you and your trolling pals”

            “name calling”

            But I do enjoy imagining you saying “hissy and prissy” in an English accent with a strong lisp. ; )

            “You follow the trolling script to the letter.” — I wasn’t aware there was a script; did you write it? :)

            On the topic of the snowpack, it’s already been explained that in many places in the Northern hemisphere, there’s been increased precipitation this past year — not a trend hung back several years or decades, countering the long-term trend in melting. But feel free to cherry pick to your contrarian heart’s hissy and prissy desire. 😉

          • OWilson

            Thank you for finally posting something on topic, but as usual, long after you have killed the thread!

            Bye Mikey! :)

          • OWilson

            Ah, the Russian conspiracy!

            Whatever gets you folks through the night!


          • Mike Richardson

            Russian!? What the — I was referring to your ironic statement that ad hominem attacks and appeals to authority were best at home ” in religion, today’s college campus, or North Korea! ” North Korea, a current communist nation. Jeez, you’re as dense as a neutron star. As for “conspiracy,” I’ll leave conspiracy theories to the guy who thinks “militant compatriots” are personally targeting him for cyber attacks! Man you just can’t quit embarrassing yourself with these posts, can you? 😂

          • OWilson

            Your losing it again, Mikey!

            That’s when I know its time for me to bail!


          • Mike Richardson

            I’d say I’m far less dangerous than someone who projects his own hate of the other onto someone else for simply disagreeing with him. Particularly someone whose far right-wing ideology is much closer to that of most mass shooters ( or Tim McVeigh — remember his anti-government philosophy in action? There was a threat to the lives of government employees, and their children). I suppose to use your reasoning, such individuals should be described as”your more militant compatriots, ” right? They do have stricter gun laws in the Dominican Republic, or at least better screening for the mentally ill seeking to purchase guns, I hope.

          • OWilson

            Get help, please!

          • Mike Richardson

            “Trump would have been my choice!” And given what we’ve seen in the past year (heck, try the past week), that says a great deal about you, unfortunately.

          • OWilson

            You work for the government you say!

            Trump and his Cabinet were duly elected!

            Do you work for the Postal Office?

          • Mike Richardson

            “We be reading?” You be reading? LOL! I thought you were a native English speaker. Don’t worry, Wilson, I do believe in law and order, as does Robert Mueller. 😁

          • OWilson

            Then suck it up! Trump ain’t going nowhere!

            As usual, I’m open to a little wager, but in spite of my previous offers, you’d never put your moey where your mouth is, right, snowflake? :)

            By the way, sorry for using Ebonics, (which has roots in the regional dialects of 17th-century Great Britain – Slate)

            I’ll try to talk “white” in future to you silk stocking socialists! :)

          • Ed Norris

            Alternative viewpoints may be welcome in a discussion of politics, but when discussing science, alternative opinions must be supported by evidence. Something your constant trolling conveniently ignores. Science depends on a consensus of evidence. And your inattentiveness to the evidence is horrific and embarrassing. Lucky for you you are shameless. Meanwhile, less fortunately for the rest of us, we all suffer for your Dunning Kruger syndrome.

          • OWilson

            My comments above were factual.

            Which part don’t you understand?

            Just ask, stop the illiterate and infantile name calling and I will explain my comments!

            If you have a question about my comments in any other blog, please post them there!

            That’s two strikes for you!

      • rrocklin

        Yes and it is cold in my back yard.

        • OWilson

          This time of the year we call that winter! :)



ImaGeo is a visual blog focusing on the intersection of imagery, imagination and Earth. It focuses on spectacular visuals related to the science of our planet, with an emphasis (although not an exclusive one) on the unfolding Anthropocene Epoch.

About Tom Yulsman

Tom Yulsman is Director of the Center for Environmental Journalism and a Professor of Journalism at the University of Colorado, Boulder. He also continues to work as a science and environmental journalist with more than 30 years of experience producing content for major publications. His work has appeared in the New York Times, Washington Post, Audubon, Climate Central, Columbia Journalism Review, Discover, Nieman Reports, and many other publications. He has held a variety of editorial positions over the years, including a stint as editor-in-chief of Earth magazine. Yulsman has written one book: Origins: the Quest for Our Cosmic Roots, published by the Institute of Physics in 2003.


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