[pct-l] Heavy Snowpack Prediction

[CHUCK CHELIN]

Good morning, Chris,



As important as water is to the economy of California it is understandable
that they would have massive quantities of data and the very best available
seasonal predictive methods.  California water resource managers are
primarily concerned with reservoir reserves, but to predict reserves it is
necessary to closely follow the mountain snowpack accumulation in the
numerous major river drainage systems, mostly flows that drain the Sierras.



As with most technical investigations, the difficulty is seldom due to a
lack of data but due to an inability to understand and appreciate the
significance of the data we know have.  Two significant data sources are the
Department of Water Resources, California Data Exchange Center Menus:
http://cdec.water.ca.gov/cgi-progs/products/ , and,
http://cdec.water.ca.gov/cgi-progs/lsproducts  Those hundreds of esoteric
reports are nauseating in their abundance and detail, and reading them will
likely require more time than actually hiking the PCT.



You can find data concerning the presence of El Niño and La Nina ocean
conditions through the years but the question remains how those conditions
equate to actual snowpack accumulation in the mountains.  One very practical
graphic history of western snow accumulation can be found at National
Resources Conservation Service (NRCS) Mountain Snowpack Maps for the Western
United States:  http://www.wcc.nrcs.usda.gov/cgibin/westsnow.pl  At this
site look at the May selection button for the various El Niño and La Nina
years in question.  The mountains of California, Oregon, and Washington show
an astounding swing in snowpack accumulation among the last 10-15 years.  Roll
the dice and guess what will prevail in 2010.



The data I like to follow for the current year’s Sierra snowpack is a graph
that plots the seasonal snowpack reporting between October 1 and the
following September 30.  The 2008-2009 seasonal graph can be seen at:
http://cdec.water.ca.gov/cgi-progs/products/PLOT_SWC.2009.pdf   I haven’t
yet found the posting of the 2009-2010 graph.  It will probably be titled
http://cdec.water.ca.gov/cgi-progs/products/PLOT_SWC.2010.pdf , but we are
now only two days into the new water season.  The current year’s chart is
usually updated approximately daily, and I like to view the progress of the
current year compared to selected previous years.  The graph may evolve high
or low, but the important question is what the snowpack level may be at the
calendar point when I intend to enter the South Sierras.

Good luck.  I find it great fun to follow the seasonal graphs.


Steel-Eye

Hiking the Pct since before it was the PCT -- 1965

 http://www.trailjournals.com/steel-eye

 http://www.trailjournals.com/SteelEye09

On Thu, Oct 1, 2009 at 11:46 AM, Paul Bodnar <paulbodnar at hotmail.com> wrote:

>
> I just looked at the snow pack levels from 1958 to 2009 at Bighorn Plateau
> (BGH) in the High Sierra and found that the average snow pack was 60 inches.
>  This translates to an average Kennedy Meadows Day of June 19 (Kennedy
> Meadows Day= June 1 + April Snow Depth at BGH/3.5).  Looking at El Nino
> years, 1958, 66, 78, 88, 93, 95 and 03 I found that the snow pack was on
> average 71 inches, with an average Kennedy Meadows Day of June 22.  Looking
> at the Strong El Nino years, 1973, 83, 92, and 98 I found that the snow pack
> was on average 90 inches, with an average Kennedy Meadows Day of June 27.
>
>
>
> On an encouraging note, the snow pack in 1992, a Strong El Nino year, was
> just 37.3 inches, a Kennedy Meadows Day of June 13.  So predicting the snow
> pack for any specific year based on El Nino would be difficult.  However, on
> average the snow pack appears to be greater on El Nino years.
>
>
>
> Paul
>
> > From: saintgimp at hotmail.com
> > To: freecook at prodigy.net; pct-l at backcountry.net
> > Date: Thu, 1 Oct 2009 10:47:56 -0700
> > Subject: Re: [pct-l] Heavy Snowpack Prediction
>  >
> > Chris wrote:
> > >
> > I've read a couple of predictions recently of heavy snow in the Sierras
> this
> > coming Winter due to the El Nino in the Pacific.  Has anyone else heard
> > anything similar, or have experience from prior El Nino years?  Does El
> Nino
> > normally result in a heavy snow pack?
> > >
> >
> > I don't know anything about predictions for the Sierra, but El Nino years
> > typically result in smaller snowpacks in Washington because the jetstream
> > often splits and runs storms to the north and south of us.
> >
> > Eric
> >
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