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Re: Snow water content vs depth

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  • richard long
    Is that Sawmill Lake or Sawmill Pass you are looking at? I can t see a station for Sawmill Pass, but there is one for Sawmill Lake.  In any case, I don t
    Message 1 of 14 , Apr 24, 2013
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    Is that Sawmill Lake or Sawmill Pass you are looking at? I can't see a station for Sawmill Pass, but there is one for Sawmill Lake.  In any case, I don't believe Sawmill Pass is really an equivalent indicator for Glen Pass, which is about 12K, and more of a west side Sierra pass that holds snow longer than Sawmill on the main crest.  I am attaching a photo from Lone Pine Lake(10K- Whitney trail) taken this past weekend. Snow levels are low for this time of year south of Forester, but there is still some snow.
    Regards,

    Richard Long
  • Chris
    Richard - it was Sawmill Pass. I believe the CDEC acronym is SWM. Nice photo btw - looking forward to seeing similar scenery in person in a couple months.
    Message 2 of 14 , Apr 24, 2013
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      Richard - it was Sawmill Pass. I believe the CDEC acronym is SWM. Nice photo btw - looking forward to seeing similar scenery in person in a couple months.

      Chris

      --- In johnmuirtrail@yahoogroups.com, richard long <rcarllong@...> wrote:
      >
      > Is that Sawmill Lake or Sawmill Pass you are looking at? I can't see a station for Sawmill Pass, but there is one for Sawmill Lake.  In any case, I don't believe Sawmill Pass is really an equivalent indicator for Glen Pass, which is about 12K, and more of a west side Sierra pass that holds snow longer than Sawmill on the main crest.  I am attaching a photo from Lone Pine Lake(10K- Whitney trail) taken this past weekend. Snow levels are low for this time of year south of Forester, but there is still some snow.
      > Regards,
      >
      > Richard Long
      >
    • richard long
      Interesting that the SWM sensor elevation is stated as 10,200 on the site. Sawmill Pass is about 11,400 . I don t recall seeing the sensor while I was there,
      Message 3 of 14 , Apr 25, 2013
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        Interesting that the SWM sensor elevation is stated as 10,200' on the site. Sawmill Pass is about 11,400'. I don't recall seeing the sensor while I was there, but I always assumed it was closer to the lake, which is about 10000'. Please pass on the info if you get there this year and see the sensor, I like that area, and keep an eye on that reading.  In regards to the original question about crampons, if you are going in a couple of months, I believe it is highly unlikely that you would need crampons this year, unless there are some late storms. The last 500' before the pass narrows and has more shade, and  tends to hold some snow, but I doubt there will be much if any there in late June  this year. But that is just my opinion.

        Richard Long
      • nedtibbits
        Hey, just to add... Mountain Education will be on the JMT between Crabtree and Kearsarge May 13th to the 16th. We will let everyone know what the on-trail
        Message 4 of 14 , Apr 25, 2013
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          Hey, just to add...
           
          Mountain Education will be on the JMT between Crabtree and Kearsarge May 13th to the 16th. We will let everyone know what the on-trail conditions are like when we get back!
           
           
          Ned Tibbits, Director
          Mountain Education
          www.mountaineducation.org
           
          Sent: Thursday, April 25, 2013 9:27 AM
          Subject: [John Muir Trail] Re: Snow water content vs depth
           
           

          Interesting that the SWM sensor elevation is stated as 10,200' on the site. Sawmill Pass is about 11,400'. I don't recall seeing the sensor while I was there, but I always assumed it was closer to the lake, which is about 10000'. Please pass on the info if you get there this year and see the sensor, I like that area, and keep an eye on that reading.  In regards to the original question about crampons, if you are going in a couple of months, I believe it is highly unlikely that you would need crampons this year, unless there are some late storms. The last 500' before the pass narrows and has more shade, and  tends to hold some snow, but I doubt there will be much if any there in late June  this year. But that is just my opinion.

          Richard Long

        • Chris
          I received this personal email from someone in our group (did not provide a name) which seems very informative so I thought it would be good to share with the
          Message 5 of 14 , Apr 25, 2013
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            I received this personal email from someone in our group (did not provide a name) which seems very informative so I thought it would be good to share with the JMT group as a whole.

            Chris

            * * *

            Chris, actually there are a few things going on to think about when looking at snow depth and snow water content. Yes, snow consolidates (becomes more dense) over time due to self weight of the snow above, freeze/thaw cycles, and other processes. Consolidation will compact the snow and therefore reduce the depth of snow depth, but consolidation does not affect the equivalent water content in the snow. The water content is set once the snow accumulates on the ground, it is what it is. The water content of the snow can only change by getting more precipitation or by melting enough to cause runoff. The snow blanket sensors on the internet can be misleading, especially as to depth. But in your example, since the water content increased, it indicates more precip occurred during the time frame you looked at. Since the depth decreased, the precip was probably rain, which helped consolidate the snow pack. Whether or not it turned to fluffy slush or icy crust depends on the local conditions (direct sun, evening temps etc).

            The daily temp cycle in the Sierra's typically goes above and below freezing most days, which increases consolidation leading to "Sierra Cement." During the cold winter, the melting doesn't actually runoff, it just refreezes deeper in the snow. As the days warm up and get much longer than the nights, melting gets vigorous enough to start running off from the pack along the ground and increases rapidly as the air temps rise.

            Most hikers are generally more concerned about snow coverage moreso than water content, or even depth. By spring hiking season, it will usually be well consolidated Sierra Cement - firm in the morning, softening in the afternoon, especially in the sun. It really doesn't matter how much water is in the snow you are walking on. If it's more than a foot deep, than it might as well be 20 ft deep, you can only sink so much. The question is how much of the trail has snow - and the snow depth data is better to gauge that. There is also satellite data to help assess general conditions.

            Lastly, the depth of a creek or river varies throughout the day, depending on the path that the water takes on it's way down from the center of the snowpack (high on the mountain) to where you are crossing. As Ned wrote, creek stage (depth) is typically low in the early morning, but the lowest depth of the day can occur later in the day. It can be surprising in some places. The end of the day and early evening is typically the deepest, with maximum afternoon melt over and some time available for the water to arrive.

            If I sound like a know-it-all, I apologize. I'm a professional in the water resources business, but I still might write something misleading.

            --- In johnmuirtrail@yahoogroups.com, "Chris" <crhall41@...> wrote:
            >
            > I was checking out snow information on the CDEC web site and am somewhat unsure if my interpretation of the data is correct. For example the Bishop Pass site (BSH) shows that snow depth has dropped from 14 inches since March 25th (from 34" to 20") yet the snow water content has increased from 14.20" to 16.40". My interpretation is that warm weather has turned soft fluffy snow into compacted slushy snow.
            >
            > Mr Ditti/Others - can you confirm?
            >
            > thanks, Chris
            >
          • Chris
            Richard, John Ditti responded to me via email and confirmed your suspicion. The SawmIll site is not Sawmill pass rather is actually located north and
            Message 6 of 14 , Apr 25, 2013
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              Richard,
              John Ditti responded to me via email and confirmed your suspicion. The SawmIll site is not Sawmill pass rather is actually located north and downslope of Bishop Pass. It is at 10,200 ft elevation but is on the dryer east side of Sierra Nevada range thus the lack of snow. John also mentioned that the snow depth measurements are to be believed more than the water content measurements (as provided by the remote sensors).

              Chris

              --- In johnmuirtrail@yahoogroups.com, richard long <rcarllong@...> wrote:
              >
              > Interesting that the SWM sensor elevation is stated as 10,200' on the site. Sawmill Pass is about 11,400'. I don't recall seeing the sensor while I was there, but I always assumed it was closer to the lake, which is about 10000'. Please pass on the info if you get there this year and see the sensor, I like that area, and keep an eye on that reading.  In regards to the original question about crampons, if you are going in a couple of months, I believe it is highly unlikely that you would need crampons this year, unless there are some late storms. The last 500' before the pass narrows and has more shade, and  tends to hold some snow, but I doubt there will be much if any there in late June  this year. But that is just my opinion.
              >
              > Richard Long
              >
            • k2poohtri
              Hello Ned, I will be highly interested in your findings as I m planning on starting my SOBO at Tuoloumne on May, 31 (I know, the area your in is about 2 weeks
              Message 7 of 14 , Apr 29, 2013
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                Hello Ned, I will be highly interested in your findings as I'm planning on starting my SOBO at Tuoloumne on May, 31 (I know, the area your in is about 2 weeks out from when I start but any knowledge will help). I know it's a low snow year, but there's still snow and the still snow melt, hence high water flow.

                If you could please email me the trail conditions I would greatly appreciate it. k2pooh15@...

                Thanks,
                Korina

                --- In johnmuirtrail@yahoogroups.com, <ned@...> wrote:
                >
                > Hey, just to add...
                >
                > Mountain Education will be on the JMT between Crabtree and Kearsarge May 13th to the 16th. We will let everyone know what the on-trail conditions are like when we get back!
                >
                >
                > Ned Tibbits, Director
                > Mountain Education
                > www.mountaineducation.org
                >
                > From: richard long
                > Sent: Thursday, April 25, 2013 9:27 AM
                > To: johnmuirtrail@yahoogroups.com
                > Subject: [John Muir Trail] Re: Snow water content vs depth
                >
                >
                > Interesting that the SWM sensor elevation is stated as 10,200' on the site. Sawmill Pass is about 11,400'. I don't recall seeing the sensor while I was there, but I always assumed it was closer to the lake, which is about 10000'. Please pass on the info if you get there this year and see the sensor, I like that area, and keep an eye on that reading. In regards to the original question about crampons, if you are going in a couple of months, I believe it is highly unlikely that you would need crampons this year, unless there are some late storms. The last 500' before the pass narrows and has more shade, and tends to hold some snow, but I doubt there will be much if any there in late June this year. But that is just my opinion.
                >
                > Richard Long
                >
              • Ned Tibbits
                No problems, Korina, but would you email me again after I get back from our SAC trip to remind me of your need? Since we’ll be leaving in a week after the
                Message 8 of 14 , Apr 29, 2013
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                  No problems, Korina, but would you email me again after I get back from our SAC trip to remind me of your need? Since we’ll be leaving in a week after the SAC to do a one-week SIC, things get a bit busy in the turn-around!
                   
                   
                  Ned Tibbits, Director
                  Mountain Education
                  www.mountaineducation.org
                   
                  From: k2poohtri
                  Sent: Monday, April 29, 2013 1:22 PM
                  Subject: [John Muir Trail] Re: Snow water content vs depth
                   
                   


                  Hello Ned, I will be highly interested in your findings as I'm planning on starting my SOBO at Tuoloumne on May, 31 (I know, the area your in is about 2 weeks out from when I start but any knowledge will help). I know it's a low snow year, but there's still snow and the still snow melt, hence high water flow.

                  If you could please email me the trail conditions I would greatly appreciate it. mailto:k2pooh15%40gmail.com

                  Thanks,
                  Korina

                  --- In mailto:johnmuirtrail%40yahoogroups.com, <ned@...> wrote:

                  >
                  > Hey, just to add...
                  >
                  >
                  Mountain Education will be on the JMT between Crabtree and Kearsarge May 13th to the 16th. We will let everyone know what the on-trail conditions are like when we get back!
                  >
                  >
                  > Ned Tibbits, Director
                  > Mountain
                  Education
                  > www.mountaineducation.org
                  >
                  > From: richard long
                  > Sent: Thursday, April 25, 2013 9:27 AM
                  > To:
                  href="mailto:johnmuirtrail%40yahoogroups.com">mailto:johnmuirtrail%40yahoogroups.com
                  > Subject: [John Muir Trail] Re: Snow water content vs depth
                  >
                  >
                  > Interesting that the SWM sensor elevation is stated as 10,200'
                  on the site. Sawmill Pass is about 11,400'. I don't recall seeing the sensor while I was there, but I always assumed it was closer to the lake, which is about 10000'. Please pass on the info if you get there this year and see the sensor, I like that area, and keep an eye on that reading. In regards to the original question about crampons, if you are going in a couple of months, I believe it is highly unlikely that you would need crampons this year, unless there are some late storms. The last 500' before the pass narrows and has more shade, and tends to hold some snow, but I doubt there will be much if any there in late June this year. But that is just my opinion.
                  >
                  > Richard
                  Long
                  >

                • K2pooh15
                  Hello Ned, absolutely. Enjoy the trips and good luck with the short turn-around. :-) Korina Sent from my iPad ... Hello Ned, absolutely. Enjoy the trips and
                  Message 9 of 14 , Apr 29, 2013
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                    Hello Ned, absolutely. Enjoy the trips and good luck with the short turn-around. :-)

                    Korina
                    Sent from my iPad

                    On Apr 29, 2013, at 4:12 PM, "Ned Tibbits" <ned@...> wrote:

                     

                    No problems, Korina, but would you email me again after I get back from our SAC trip to remind me of your need? Since we’ll be leaving in a week after the SAC to do a one-week SIC, things get a bit busy in the turn-around!
                     
                     
                    Ned Tibbits, Director
                    Mountain Education
                    www.mountaineducation.org
                     
                    From: k2poohtri
                    Sent: Monday, April 29, 2013 1:22 PM
                    Subject: [John Muir Trail] Re: Snow water content vs depth
                     
                     


                    Hello Ned, I will be highly interested in your findings as I'm planning on starting my SOBO at Tuoloumne on May, 31 (I know, the area your in is about 2 weeks out from when I start but any knowledge will help). I know it's a low snow year, but there's still snow and the still snow melt, hence high water flow.

                    If you could please email me the trail conditions I would greatly appreciate it. mailto:k2pooh15%40gmail.com

                    Thanks,
                    Korina

                    --- In mailto:johnmuirtrail%40yahoogroups.com, <ned@...> wrote:
                    >
                    > Hey, just to add...
                    >
                    > Mountain Education will be on the JMT between Crabtree and Kearsarge May 13th to the 16th. We will let everyone know what the on-trail conditions are like when we get back!
                    >
                    >
                    > Ned Tibbits, Director
                    > Mountain Education
                    > www.mountaineducation.org
                    >
                    > From: richard long
                    > Sent: Thursday, April 25, 2013 9:27 AM
                    > To: mailto:johnmuirtrail%40yahoogroups.com
                    > Subject: [John Muir Trail] Re: Snow water content vs depth
                    >
                    >
                    > Interesting that the SWM sensor elevation is stated as 10,200' on the site. Sawmill Pass is about 11,400'. I don't recall seeing the sensor while I was there, but I always assumed it was closer to the lake, which is about 10000'. Please pass on the info if you get there this year and see the sensor, I like that area, and keep an eye on that reading. In regards to the original question about crampons, if you are going in a couple of months, I believe it is highly unlikely that you would need crampons this year, unless there are some late storms. The last 500' before the pass narrows and has more shade, and tends to hold some snow, but I doubt there will be much if any there in late June this year. But that is just my opinion.
                    >
                    > Richard Long
                    >

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