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[pct-l] SNOW PAGE

I added a couple more snow sensor stations to the Southern PCT Snow Page.
One is near Echo Peak and the other near Squaw Valley. These additions kind
of fill the gap for the northern part of the Sierras. With the talk of
folks skipping around the Sierras, I thought it would be useful to track a
couple sensors in the Lake Tahoe area. As always it can be found at:

http://www.bigsky.net/mdixon/snow/snow.htm

I too have been wondering about alternative plans due to the snow
conditions in the Sierras. The discussion on that topic has been excellent
so far. The latest word from the World Meteorological Organization (WMO) is
that El-nino will continue to have a major effect on weather patterns
through May of this year. This means that the snow levels are likely to
continue to increase at the higher elevations through April.

In response to TednDeb's post, even if precipitation falls in the form of
rain it won't melt much snow. Rain adds some energy to the snow pack, but
overall the effect of rain on snow is negligible. For example, it takes 8
inches of rain at 50 degrees F to melt just 1 inch of snow (water
equivalent). According to Linacre (1992), factors for melting snow in order
of importance are: 1. direct solar radiation 2. warm wind (convection) 3.
condensation and rain. Studies in California show that in April and May the
net irradiance (direct solar radiation) is about 3 times the convective
energy flux (wind). What does this mean for snow melt in an el-nino year?
If solar radiation is reduced due to cloudy days etc. then the snow pack
will receive significantly less energy overall on a daily basis. The result
is that the snow pack will persist until it reaches a point where
additional energy actually melts the snow, which will be much later in the
spring. Hope this answers your question.

Mark Dixon (Yeti)

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