image of snow from JD

Image submitted by John Dittli

Still need at least two more similar (huge) storms to reach normal snowpack
There has been lot of hype about the recent storms and yes, indeed, the snowpack is looking good in Mammoth and the Central Sierra right now, with more than 50 percent of normal, or half, of what the Sierra normally gets IN AN ENTIRE WINTER already on the ground.
That said, many a winter has started off very well and then, the spigots shut off in January or February and never again turn on.
While no one is predicting that will occur, neither is anyone predicting it will not.
Should the storms stop, the Sierra could end up by April 1, the last day winter snowpack is measured by the state and by DWP, with only about half of what is normal for the winter. To explain this, snow surveyor for the state of California John Dittli may have said it best.
"At the beginning of each month from Feb-May, ground crews measure actual snow depth and density in hundreds of locations throughout the Sierra, twenty being at or above 10,000’ along the JMT (there is a reason we don’t take measurements higher, that is one of the nuances.)" he said on Jan. 6. "That data is then compared to data that has been collected monthly over the last 90 years to create a percentage of average over that time. There is no “guessing”, this is actual human gathered data (well actually there is some guessing discussed later).
"There are many nuances to Sierra snowpack that has always challenged arial sensing and to a certain degree remote ground sensing. Because of this, making any forecasts off such data becomes, at best, problematic. I’ll get into those nuances at a later date for those interested.
"For now, here is a graph that shows why making a forecast this early in the season is rather pointless regardless of the data source.
"While the December storms were big, the resulting snow pack was not all that unusual. In the past two decades there have been five other winters that have resulted in packs of relatively equal magnitude. Here is the kicker; of those, three ended up well below average and two above. That is to say, we currently only have half our annual snow and we are going into a typical January thaw that is likely going to keep us dry (Flat lined) to near months end, after that only time will tell."

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