The Alta snowstake cam suggests we're getting more action that may have been advertised by the models with perhaps 6-7 inches on the stake earlier this morning before the ski patrol wipe (kudos to my friends at OpenSnow for producing the Alta Snow Stake time laps so I could grab this image).
And then another inch was added since then (not shown).
The automated sensors are coming in a bit below that with about a 6" increase in the total snow depth and 6" on the interval board (ignore the spurious 34 reading at 08:00).
Those numbers are a bit higher than advertised by the HRRR and GFS over the past few runs. Below are the forecasts for Alta-Collins going back to 0000 UTC 12 December for snowall amounts through 9 AM this morning. Only one of the HRRR runs went for 6" and the most recent was only an inch. The GFS was a bit more optimistic overall, but never got above 4.5 inches.
0Z 12 Dec HRRR: 1.1”
6Z 12 Dec HRRR: 6.0”
12Z 12 Dec HRRR: 3.3”
18Z 12 Dec HRRR: 2.4”
0Z 13 Dec HRRR: 1.0”
6Z 13 Dec HRRR: 1.0”
0Z 12 Dec GFS: 0.0”
6Z 12 Dec GFS: 3.7”
12Z 12 Dec GFS: 2.5”
18Z 12 Dec GFS: 3.4”
0Z 13 Dec GFS: 4.5”
6Z 13 Dec GFS: 4.5”
Consider yourselves blessed. Let's hope the snow keeps coming as we need all we can get.
Is this an example of the "blower pow" the models struggle to capture? still snowing nicely in Alta and the sun is poking through
ReplyDeleteLooks like something around 25:1. That is on the upper end of what our machine learning models *could* predict. The forecast snow-to-liquid ratios for 1 AM to 9 AM were 13:1 to 19:1 depending on the hour, so the forecast SLRs were low. That's a common occurrence when we're in the 20:1 or higher snow to liquid ratos.
DeleteIt's been a while since I have thought about this calculation, but Utah Avy reported 0.2" SWE. Is the density 6" / 0.2" = 30%? That seems wrong. Sorry for the nube question. What am I missing here? I need a refresher...
ReplyDeleteThe Utah Avy report comes out earlier than 9 AM. They reported 5" with .2 water, which would be 25:1 snow-to-liquid ratio or 4% water content.
DeleteI understand now! Thank you for the refresher!
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