Solid Delivery by Mother Nature

Some pretty solid numbers coming in for everyone in the Wasatch. Alta Collins up to 1.43" of water and 16" of snow through 7 AM, with the latter reflecting lower densities overall than I expected for this storm in Sunday's post.  A look at reports from around the area shows solid numbers from Sundance to Snowbasin, including the Wasatch Back, although the high snow level may have resulted in some mixed precipitation at the base of Sundance.

The time series of temperature and dewpoint from the base of Snowbasin shows the classic "ice cube" effect with temperatures hovering right near 32˚F throughout the period, a consequence of the melting of heavy snowfall preferentially cooling the temperature to the melting point.  

We are moving into a bit of a break this morning, although snowshowers may continue at times in the mountains.  The next storm moves in this afternoon and looks to continue into tomorrow.  

The next storm features a bonafide trough passage and possibly a frontal band pushing through northern Utah from the west.  The 12Z HRRR forecasts this band to be over western Utah at 6 PM MST this evening (0100 UTC 11 January).  

Our HRRR-derived forecast guidance for Little Cottonwood shows a total accumulations from 5 AM this morning until 5 PM Wednesday of 2.54" of water and 25" of snow.  If you deduct everything before this morning's break, the totals from about noon today through 5 PM Wednesday is 2.21" of water and 22" of snow.   

The GFS-derived product is from six hours earlier (the 1200 UTC GFS isn't available yet), but the totals from noon today until 5 PM Wednesday are 1.31" of water and 17 inches of snow.  

Much like yesterday and last night, this storm is still a mild one through this evening.  Snow levels will likely be near 6000 feet today, before dropping overnight to the valley floor.  Forecast snow to liquid ratios for the storm are generally in the 10 to 15 to 1 range for Alta-Collins, which is near average, with a trend toward higher values, meaning the snow is likely to be right-side up come tomorrow.  

Based on these model forecasts, I'm expecting an additional 1.25-2.25" water and of 14-22" of snow at Alta-Collins from noon today through 5 PM Wednesday.  

Backcountry trailbreaking tomorrow could be beastly and the avalanche conditions may be such that the safer low-angle terrain doesn't provide enough hill for good skiing.  Much may depend on how supportable last night's snow is and how right side up things are with the next storm.  These are definitely not Goldilocks conditions.