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Perspectives on the 2015/16 Snow Season

Erik Steenburgh gets some freshies in the Big Cottonwood Backcountry

We are now into April and the time has come to reflect on the 2015/16 snow season and my view is that it has been OK, but not all that great, but coming on the heels of 2014/15, it seemed pretty good.

First, let's talk about the ingredients of a great ski season.  First, there needs to be considerable snowfall during the early season (October and November) to build up a base for resort skiing during the holidays and, more importantly for backcountry skiing when the sun is at its lowest angle around the winter solstice.  Building up an early base also helps minimize the development of depth hoar and related avalanche problems in the backcountry snowpack.  Second, the snow needs to come in storms that are modest in size, which keeps the resorts and backcountry fresh while minimizing avalanche hazard.  Finally, such storms need to keep coming through March.  

This year we had one out of three.  During the early season, snowfall was limited and through about 10 December, snowpack (green line below) and snowfall were well below average (blue line below is average, magenta line median).  Conditions were bony and we had a thin, weak snowpack that, although eventually strengthening, led to backcountry avalanche concerns.  

The pre-Christmas storm cycle saved our bacon and helped to turn the season around.  It also provided a low-elevation snowpack that greatly improved backcountry access, especially compared to 2014/15.  

We then lucked out through about mid February when a succession of modest storms made for fairly good ski conditions.  An interesting aspect of this season compared to last season is that at the end of January, the water content of the upper-elevation north facing snowpack at Snowbird was virtually the same (see graph above).  Nevertheless, the skiing this year was certainly better as the snow came in a series of storms rather than a smaller number of large dumps (note the staircase-like structure of the snowpack trace from last year - red line above).  

Tracks following one of the many modest "Goldilocks" storms in January and early February

By early February, a big late February and March would have probably made this a pretty good season, but it didn't happen.  We went into drought from mid Feb to early March, with the sun doing its damage to the south side of the compass.  Things have subsequently picked up, and there has been some good skiing, but the spigot never fully opened.

March brought some decent powder skiing, but not enough storms to raise it to an above average level

As things stand today, Snowbird sits at 89% of median snowpack water equivalent, which puts us just below about half of the years since SNOTEL records began in 1990.  Alta ski area reports 382 inches to date, compared to a long-term average for Oct-Mar of about 412 inches.  Thus, in both instances, we sit just below par.

So, my view is that this has been an OK but not great snow year and ski season.  I suppose I could update that in early May if things really opened up later this month, but its hard to persuade me with snow that late in the year.  I prefer my dumps in November and December.  

If you wish to argue that this has been a great ski season, let me show you a couple of examples of what a big snow year looks like.  Here's a SNOTEL plot with the 2010/11 and 2004/05 seasons overlaid.  How about nearly double snowfall and snowpack.  

After 5 years of below or just below snow, will 2016/17 finally bring the storms?  Let's hope so.

Add your perspectives to the comments.  

No Speed Limit Today

I haven't done much lift-served skiing this winter, but all indicators pointed to great conditions for high-speed zooming with no speed limit today and that's exactly what we found at Alta.  Conditions on the north-facing groomers were not to soft and not to firm, but just right.

We capped the three hours of cruising with lunch at the Lone Star, one of my favorite apres-ski spots.

I learned, however, that after skiing groomers, the half burrito is sufficient.  I need to save the full size for after long tours.  Full-size Lone Star burrito 1, Professor Powder 0.  Hopefully Syracuse will fare better against North Carolina tonight.

Splendid Weekend Ahead

The weekend weather is looking splendid with a high amplitude ridge in full control.

High temperatures in the valley will be in the 60s.  It will be a perfect weekeng for driving home from skiing in flip flops, drink a beer in the sun, and having a BBQ.  'Nuff said.

The Imperative to Ski Now

It's late March, there's deep powder to be had on the north half of the compass, and it is imperative you ski now.  The weekend is looking warm and ridgy, and perhaps some north aspect powder will survive, but probably not a lot.  Get out there ASAP.

Stuff We Know About This Storm and Stuff We Don't

It's always great to be greeted by post-frontal snowfall in the morning.

I've been taking a look at the various model forecasts and I have to say that this is one of the most complicated storms I can remember.  There are a variety of frontal positions, low-center tracks, and precipitation distributions and intensities being forecast by the various models and their ensembles that make forecasting details very difficult.

For simplicity, I'm going to use only the 0600 UTC NAM to illustrate some of the issues at play.  The red dot and yellow plus sign are located at the approximate location of Alta.  One can see the frontal band that is over us this morning in the early part of the loop,  Then a narrow band sets up very close to Alta, followed by more scattered precipitation.

Those precipitation features are very narrow and small in scale and predicting their intensity and position with any accuracy is very difficult.  One can imagine how a slight change in location is the difference between heavy snowfall and no snowfall at any given time, and that's assuming the model forecast has a reasonable handle on what Mother Nature will do.

If we look at the time series of 3-hour accumulated precipitation, we see quite a bit of "pulsiness" with some periods of moderate precipitation and periods of less precipitation.

One can look at the GFS, HRRR, or NCAR ensemble and find all sorts of variations in the timing and intensity of precipitation features over the next 48 hours or so.  Below is the NCAR ensemble.  The box-and-whisker plots in the bottom frame show the wider range of possible precipitation rates being forecast by the ensemble members each hour at Alta.  Total accumulations range from a bit under an inch to a bit over two inches.

So, let's start with what we know.  Winter has returned and we are going to see periods of snow over about the next 48 hour period.

What we don't know is the details of where and when the snow will come (other than some snow continuing this morning).  For Alta-Collins, I think the most likely range of totals by 6 AM Wednesday is 0.7 to 1.4 inches of water and 8-16 inches of snow.  We could do better or worse depending on how things develop.  I expect to see quite a bit of spatial variability in snowfall from this event (Powder Mountain is already reporting 5 inches).  Thus, be patient and go where and when it snows.  I expect there will be some good skiing to be had and a modest event would actually be better than a big one, at least for my skiing interests.