Today was “Melt-Out Day” on Mt. Hood

Have you ever wondered how long it takes all the snow in the Cascades to melt?  Of course it depends on the elevation, with higher elevations (cooler temps) taking longer.  Well today was the day the Mt. Hood Test Site saw the last of its snow melt.  Actually the snow depth sensor finally went to zero yesterday, but the “snow pillow” that measures snow water equivalent is still seeing a little.  I’m not a sensor expert, but decided today was close enough.

I’ve had some spare time at work the past few days, so I wanted to see if the date at that location is earlier or later than in the past.  You might be surprised at what it shows!  Data at that location at 5,400′ goes back to 1981.

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You can see the earliest was the drought year 1992 when the snow disappeared by May 25th.  The latest was just three years ago in 2011, when the last of the snow disappeared the 2nd week of August.  Now the data period is quite short; only about 30 years, so don’t try to draw any earth-shattering conclusions, but the trend is definitely for a slightly later melt-out in the past 9 years.

I think it’s fair to make these two statements as well:

1. At the 5,400′ elevation on Mt. Hood, the snow is not melting any earlier than in previous decades.  If anything it is sticking around longer.

2. The Cascade snowpack AT THAT ELEVATION and IN THAT LOCATION is sure not disappearing!

 

When I get some more time I think it would be interesting to see if lower elevation locations are similar, such as 3-4,000′ spots.

Chief Meteorologist Mark Nelsen

9 Responses to Today was “Melt-Out Day” on Mt. Hood

  1. High Desert Mat says:

    Another nice and warm day in Redmond with a high of 87 on my Davis vue, the one I won at the weather meeting last fall, and looks like many more to come. Finally summer is here and is going to stay this time according to all the current models. Sure would like some more t-storm days like we had yesterday, the ground and everything on it here is extremely and flammable right now.

  2. Dean Myerson says:

    And the date of meltout is not just a measure of snowpack (not saying you said it was), but of when the snow fell. We seem to have had a lot of late snow in recent year, and cool springs as well, making the meltout date be later than it would otherwise be.

    • Mark Nelsen says:

      That’s another good point. Total snowpack in late March or April could be getting thinner (not saying it is), but the melting is later.

  3. Tyler Mode says:

    I can tell you from being up there yesterday, the snow is still there in large patches! It just depends where it has drifted etc. I don’t have a pic of that site, but I was there. There is bare grass in some areas, and 3-6′ of snow in others.

    As for the lower elevation snow pack…I was up at Mt. Rainier a few weeks ago and was surprised how at 3,800′ there was no snow, but at 4,200′ there was a solid pack several feet deep.

  4. pdxgeologist says:

    Lots of stuff you could compare that graphic with: ENSO, PDO, Solar Cycle, Total Snowfall (early v. late season), etc…

    • Mark Nelsen says:

      Yeah, I was thinking it’s such a short period of data that the change to cold PDO could easily have caused the later melt-out the past 10 years.

  5. The Bad Forecaster says:

    Hi Mark

    Back in 2008 I did some research for Mount Rainier National Park Biologist Barbara Samora and went back through all the years to 1972 when the record snowfall of 1,122 inches ended that season. I averaged out the dates the last snow depth was measured before melt out and that date came out to July 15th. I was interning in the summer for the Student Conservation Association at Longmire all that summer in the GIS office as a natural resources planning intern. That next winter season I got hired as a ranger in the park in 2009-10 and worked one more winter after that one. I did the weather at the Paradise weather station on the weekends those two winters.

  6. Muxpux (Castle Rock 175') says:

    This time of year the snow cover is quite patchy. This must mean the solid cover is gone and now there’s just mounds of snow? I’d love to see a pic of the site.

  7. schmit44 says:

    Great research here. I always appreciate your detailed analysis Mark.

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