[pct-l] Sierra Snow

[steve_peterson at sbcglobal.net (Steve Peterson)]

In light of the recent NOAA discussion, I feel compelled to reveal that in 
mid-November I noticed that, in stark contrast to last year, there had been no 
significant snowfall in the Sierra.

Stop laughing--there's more: I wondered if this might tell us anything about the 
rest of the year. You might be inclined (as I was) to think, "Naw, way too early 
to tell--too much can happen in the next six months."

But we'd be wrong. Don't ask how I discovered this, but there is a strong 
correlation between snow water content at Tuolumne Meadows (TUM) on Dec 1 and 
the day the Upper Tyndal Creek snow sensor (UTY) (near Forester Pass) reads zero.

The average "zero day" at UTY is 12 June. The average snow water content on 1 
Dec at TUM is 3.76". An astonishing 80% of the time (over the past 26 years), if 
the water content at TUM is less than 3.76", the zero day at UTY is *before* 12 
June, and if the water content at TUM is more than 3.76", the zero day at UTY is 
*after* 12 June!

It's also somewhat proportional--that is, if the water content is a little less 
than 3.76" then the zero day is (generally) a little earlier than 12 June, and 
if the water content is a lot less than 3.76", then the zero day is a lot 
earlier than 12 June, but this correlation isn't as strong as the simple 
earlier/later correlation.

The years the correlation didn't hold, three years the zero day was later than 
12 June even though the water content at TUM was less than 3.76", and twice the 
zero day was earlier than 12 June even though the water content at TUM was 
greater than 3.76".

Now that Dec 1 has come and gone, I can report that the TUM water content as of 
1 Dec this year is 1.54" which would indicate that there is a very good chance 
(80%) that the UTY zero day will be earlier than average. Judging by past data, 
an amount of 1.54" would likely get us a zero day somewhere in the last few days 
of May through the first few days of June.

For comparison purposes, in 2004, the UTY zero day was 1 June; in 2003, it was 5 
June. Thus, you could expect that this year's hiking experience will be similar 
to those of 2003 and 2004.

But of course, there were those three exceptional years :-)

--Steve (Don't need no stinkin' NOAA)