A Pretty Good Storm

Mother Nature brought the goods over the past two days.  Here are 48-hour water equivalents for the period ending at 11 AM 5 January:

Ben Lomond Peak Snotel: 2.8"
Snowbasin Boardwalk: 2.42"
Brighton Snotel: 2.6"
Alta-Collins: 3.73"
Snowbird Snotel: 4.0"

The trace of accumulated precipitation at Alta-Collins for the period snows that most of this fell in the past 24 hours.  In fact, the water-equivalent precipitation for the 24-hour period ending at 11 AM this morning was 3.03".  I'm always impressed by storms that produce 3" of water in 24 hours.  

Source: MesoWest

It's worth noting that this was a storm period characterized by southerly to southwesterly flow that shifted to westerly during the trough passage this morning.  Below is the wind speed (red line), gust (green plus signs), and wind direction (blue circles) on Mt. Baldy for the same period as above.  Note the predominance of southerly to southwesterly flow until around 0300 MST when the flow veered to westerly.  

Northwesterly flow gets a lot of attention, but southerly and southwesterly flow can bring the goods to Alta too, typically in the form of big water.  Snowfall amounts in these events are typically "subdued" due to the low snow-to-liquid ratios, as was the case in this storm.  Out of the 3.73" of water, the total snowfall was only 21", which represents a snow-to-liquid ratio of only 5.6 to 1 (a whopping 18% water content).  Although not the Greatest Snow on Earth, that's some of the Greatest Base Builder on Earth and just what we need.

The snow depth at Alta-Collins is now 64" and we have eclipsed 10" of water equivalent at the Atwater (13.5") and Snowbird (13.2") SNOTELs.  Thus, I am officially declaring the start of "good early season ski conditions)" since I often use 60" of snow or 10" of snowpack water equivalent for that threshold.  

This may be hard to believe, but as of last night the Snowbird and Brighton SNOTELs were at 95% and 93% of median snowpack water equivalent for the date, respectively.  Elsewhere things are worse, even much worse at lower elevations, but the upper elevations continue to claw their way to respectability.