Sunday, March 25, 2018

Some Snowpack Improvements and Losses Since Mid February

Mid February marked a turning point for the upper-elevation snowpack in the central Wasatch, which now sits at 70% or more of median for this date at all four SNOTEL sites (Snowbird, Brighton, Mill D North, Thaynes Canyon). 

Source: NWS
At Mill-D North and Snowbird, you can see the gap close between the median trace (purple line) and this season's trace (green line) from about mid February to the present. 

Source: NWS
Source: NWS
These sites are relatively high, however, so they tell an incomplete picture of the snowpack.  At lower and mid elevations, the situation isn't nearly as rosy.  Sadly, those elevations are poorly sampled with regular observations and it is difficult to quantify how far behind they are.  In addition, the central Wasatch are doing much better than the northern or southern Wasatch.   Some of the more depressing SNOTEL observations are provided by Ben Lomond Peak to the north and Timpanogos Divide to the south, which set well below median. 

Source: NWS 
Source: NWS
The high terrain of the central Wasatch are a favored region for snowfall and snowpack climatologically, but this year, the situation is even more strongly amplified.

4 comments:

  1. We should expect this to be the new normal as the climate warms .

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  2. Unrelated, but what are the factors that determine the amount of post frontal precipitation?

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    Replies
    1. There are many, including the depth and instability of the cold air and northwesterly flow, amount of moisture, existence (or non-existence) of some sort of forcing feature like a trough, etc. They don't call it the post-frontal crapshoot for nothing.

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  3. Aggregating the entire Provo Jordan River Basin, the March water supply Outlook report shows precipitation tanked at the Historical minimum (at 18).

    https://www.nrcs.usda.gov/wps/PA_NRCSConsumption/download?cid=nrcseprd1386639&ext=pdf

    Kurt

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