Gentle Vertical Snowfall

We recently moved from the Palouse region of Eastern Washington to the a semi-forested bench in the Clearwater River Canyon.  There's a short list of things that the Palouse is known for:  it's among the nation's most fertile farmlands; the endless waves of rolling hills; home of the Washington State Cougs; and finally, the relentless steady winds that seem to swing mid run-or-ride to ensure a constant headwind.  One of the most enjoyable things about moving into the Clearwater Canyon has been a respite from those winds.  It's a small thing, but after many years on the Palouse, I'm not sure the last time I've seen the snow fall vertically.  

It's a sight you'll almost never see on the Palouse.  

He didn't verbalize this precisely, but I think Mister Cooper was similarly impressed with the gentle vertical snowfall.

SHORT:   Chief Joseph Wildlife Area Hike

I had a break from a seemingly endless stream of DVM admissions interviews, so we took advantage of a mild January day in the *unofficial* Washington Hells Canyon Area (specifically the Chief Joseph Wildlife Area and adjacent BLM land).   On the map, this area merely appears on the fringe of northern Hells Canyon, but actually it's in the heart of some of the most spectacular, under appreciated, and rarely explored canyon country in the US. I'll elaborate in a future post.   

On a rough path up to Lime Hill, looking east towards the Snake River

Snake River, just east of Rogersburg (WA)

Fun With Moscow Mountain SNOTEL Data

 

Begrudging snowshoe up to Paradise Point on Moscow Mountain (Winter 2017)

I’m not proud of it, but aside from the occasional Nordic ski or snowshoe, my main winter activity consists of tracking snow accumulation in the region and counting down the days to Spring and snow-free trail.  Data from the Moscow Mountain SNOTEL seems to faithfully reflect the mountain snow totals across the inland northwest, and—when combined with data from the Sourdough Gulch SNOTEL in the Northeastern Blue Mountains—is a good metric for predicting which trails within the region might be accessible for NON-winter activity.  

Looking north from Paradise Point (Winter 2017)

A related activity is comparing the current snow-depth totals on Moscow Mountain to the historical averages (i.e., “how terrible is this winter compared to previous terrible winters?”).  Let's take a moment to consider how much snow typically accumulates on Moscow Mountain during winter.  The following was pooled from data collected over the last 20 winters (2001-2020) from the Moscow Mountain SNOTEL site# 989 (elevation 4,700').  

Below is a plot of the average snow depth (with 95% confidence intervals) reported by the MM SNOTEL site for the months of Nov-May from 2001-2020:

The average maximal snow accumulation is just below 60 inches, usually occuring in late February / early March.  Note that the MM SNOTEL site is on the east side of Moscow Mountain, which receives significantly more snow than the more frequently accessed west side of the Mountain.  Of course, just looking at the average snow depth ignores the annual variability in snow accumulation that undoubtedly occurs.  To get some sense of the variability, here are the individual data sets for each year (2001-2020), with the maximum and minimum snow years highlighted.

The highest peak snow accumulation between 2001 and 2020 was 98 inches on March 21st 2002, and the lowest peak snow accumulation topped out at 23 inches on January 17th 2005. Not coincidentally, winter 2004-05 was purported to have the lowest snowpack in the WA and OR cascades since winter 1940-41 (http://www.skimountaineer.com/CascadeSki/CascadeSnow2005.html) NOTE:  NOT SECURE WEBSITE   

Visually inspecting the data above, it is apparent that early in the snow season the data is more tightly grouped around the mean snow depth, but as snow accumulates the data becomes more widely distributed about the mean.  This phenomenon is more apparent by looking at the daily snow-depth variance (i.e., the average of the squared deviation from the mean snow accumulation for each day of the snow season) .  

Generally, the snow-depth variance tends to increase as the average snow-depth increases and minimizes as snow depth decreases--which is not surprising.  However, it's interesting to note that instead of a gradual increase in the snow-depth variance, most of the increased variance is accounted for by two dramatic variance inflections (yellow boxes): the first is between late January and early February, and the second is between early and late March.  

So back to the original question:  how does winter 2020-21 compare to previous winters? The obvious caveat to this question is that we are only ~40% into this region's statistical snow season.  Nevertheless, here's an early compairison:

As of now, winter 2020-21 is looking pretty average (current snow accumulation on Jan 23 2021 is 40 inches, compared to a date-matched mean snow depth of 42.3 inches).   

One notable feature of Winter 2020-21 to date was the relatively large mid November accumulation. The MM SNOTEL recorded a 15 inch accumulation by Nov 14th--the largest mid-November accumulation recorded by the MM SNOTEL in the last 20+ years.  

 

So what does this all mean? Although current snowpack is at average levels, we are just entering the first of two high variance inflections.  It's likely that the amount of snow accumulation during the first high-variance inflection (i.e., beginning late January) differentiates between light or heavy snowpack seasons, and the second high-variance inflection (beginning early March) subsequently differentiates between historically high snowpack or an early run-off.  

 Tukeespe Hike

Tukeespe is a wildlife area outside of Cavendish Idaho and is managed by the Nez Perce Tribe.  It's located on Cream Ridge, which divides the Louse Creek drainage (to the north) and the Clearwater River Canyon (to the south).  Louse Creek Canyon is a spectacular gorge, plunging steeply from the Tukeespe grasslands.  We love visiting this area and are extremely grateful that the Nez Perce Tribe has made this accessible to visitors. The trails are primitive and are infrequently used.  It's a nice opportunity to explore a spectacular area in solitude.  

At one of the Tukeespe trailhead areas.  

Louse Creek Gorge