February 6th, 2010

Snow and Ice Report

Rocky Mountain National Park  


Unfortunately, conditions have been relatively static in RMNP the last few weeks with minimal new snow and relatively warm temperatures providing some added stability to an otherwise weak snowpack.   The ice has changed little in two weeks with warmer aspects the most dynamic and everything else slowly drying-out.

In the first week of February, less than an inch of snow accumulated at the Bear Lake Snotel station (9520') with high daytime  temperatures wavering between  21F and 41F in this time span.

As a result of little new snow and above freezing temperatures for much of the week, the CAIC has kept the avalanche danger rating for the Front Range mountains at MODERATE on the western aspects and CONSIDERABLE  on the northern through eastern aspects. 

The areas of highest avalanche potential are slopes with a shallow snowpack and less supported slopes in the upper 30 degree angle range where a generally weak snowpack still exists.  In RMNP this seems to be the situation more often in the treeline elevation range, which describes forested areas where wind loading and energized slab formation are more prevalent.

Although depth hoar (basal facets) are less common as a failure layer by this time of year, the relatively shallow snowpack has kept this scary weak layer close enough to the surface to be a layer of concern.  This strong ovor weak layaerin set-up will continue to be an issue until the snowpack is more consistently deep- hopefully before summer!

The warm weather of the Front Range has made climbing on south-facing crags in Eldo, Boulder Canyon, and even in the driveway of the Helmuth homestead perfect  for this time of year.  I spared the reader by leaving out all of the shirtless photos, but believe me, on these south-facing hills at 8,700', there have been many days when this has been very comfortable.

 
Sal Silvester and Randy Levensaler kicking steps in foot deep powder up the Dead Elk Couloir on Jan. 28th, 2010 on a ClimbingLife Guides Level 1 Avalanche Refresher Course.  A more than 15' deep snowpack in this specific location and cross-loading created perfect n0n-cohesive snow over a very thick and solid mid and lower snowpack.  

Much of the key to avoiding avalanche issues in the currently relatively shallow snowpack (1-2m) are finding those spots where the snowpack is exceptionally deep and where the wind has created strong layering, versus the strong over weak layering set-upm especially when the weak layer is composed of large, basal facets.  In this situation,  a deep snowpack is generally better. 

Click on outlined photos to enlarge.

Derek Drechsel pulling the trigger on some deep and steep skiing in the Dragontail Couloir on Feb. 5th, 2010 in preparation for our Alaskan Ski Expedition in April of 2010. We still have a few spaces left on this fantastic trip, please contact me at This e-mail address is being protected from spambots. You need JavaScript enabled to view it if you're considering joining us.

Again, deep is good, especially where slopes are structurally well supported and our main concern on this blustery day were  fresh slabs forming in the upper snowpack.  Hand shear tests cut with a ski pole along with ski cuts showed that this was not an issue during our time in the couloir.

Mountain conditions, especially in the winter and spring seasons are  incredibly dynamic and although this couloir was not our 'Plan A' for the day, through intuition (experience) and constant testing, we determined that it was a reasonable risk with considerable rewards.  Check-out the video from this fantastic ski day here.

Although I often post photos of snow test pits as a frame of reference for some typical conditions that can be found in RMNP, the point of these photos  is not to demonstrate that these are decision-making tools. My goal instead is  to illustrate some of the complex layering that is often present in the winter snowpack.

When I started studying snow from some of the top U.S. professionals in the late 1980's, I was lucky enough to be exposed to the inherent shortcomings of a purely scientific approach to decision-making in snow covered terrain.  These mistakes (which current science has proven true) were primarily based on the theory that test pits were a reliable method to determine snow stability. 

Gambling on the Super Bowl likely has greater predictive probability than gambling on a small sample of snow from a highly variable material to make a life or death decision.

My main point here, is that we do not use pits as primary decision-making tools and only human  folly would steer us in that direction.

Looking down the crux dihedral pitch of the North Face with the precipitous Chasm View below.

Above- Randy Levensaler dropping the knee in the Dead Elk Couloir on 12/28/10.

February through May are the biggest snow months in the Front Ranges,  so we have plenty of time yet for skiing season to come into shape and we're looking forward to daily forays on ski's in the months to come.

CU Professor Dan Sturgis getting in some great powder turns on a ClimbingLife Guides Level 1 Avalanche Refresher Course.  The primary goal of this field-based course is to increase each participants understanding of the dynamic nature and predictive potential of the winter snowpack.

Photos below are only representative of common conditions, they are not current.

Consult the CAIC website for current Avalanche Danger forecasts here.
 

LOW Avalanche Danger as of 2/6/10 (human caused unlikely) 

Loch Vale Ice
WI 2-5
M1-8




barely IN- bad year

LOW Avalanche Danger as of 2/6/10 (human caused unlikely)

Squid
WI 5



OUT -  too dry

Deep Freeze
WI- 5



OUT - too dry

LOW Avalanche Danger as of 2/6/10  (human caused unlikely)

Columbine Falls
WI 3-4



IN 

Necrophilia
WI 5, M5



OUT 

 
Black Lake Slabs
WI2

 

IN

The Crypt
WI-4



IN-

 NE Gully
WI3



IN

MODERATE Avalanche Danger as of 2/6/10 (human caused possible)

Flying Dutchman
WI-2



OUT

MODERATE Avalanche Danger as of 2/6/10 (human caused possible)

Martha
WI - 2, M-1



could be  IN 

Hallet's Chimney
WI-5, M-4

OUT - wait until spring

Field's Chimney
WI-5. M4



OUT

MODERATE Avalanche Danger as of 2/6/10 (human caused possible)

Alexander's Chimney
WI-4, M4



IN but thin 

and not complete

Smear of Fear
WI-5, M5



OUT

New Beginnings
WI-5, M5



OUT but forming

MODERATE Avalanche Danger as of 2/6/10 (human caused possible)

The Window
WI-5, M4



OUT

Vanquished
WI-5, M4



OUT

Hot Doggies
WI-5+



OUT but close to IN

CONSIDERABLE  Avalanche Danger as of 2/6/10  (human caused probable)

East Face, Notchtop
WI-3+, M3



IN - thin year

North American Avalanche Danger Scale

Danger Level
(& Color)

Avalanche Probability and Avalanche Trigger

Degree and Distribution of Avalanche Danger

Recommended Action
in the Backcountry

Natural avalanches very unlikely. Human triggered avalanches unlikely.

Natural avalanches unlikely. Human triggered avalanches possible.

Unstable slabs possible on steep terrain.

Use caution in steeper terrain and  on certain aspects. 

(ORANGE)

Natural avalanches possible. Human triggered avalanches probable.

Natural and human triggered avalanches likely.

Unstable slabs likely on a variety of aspects and slope angles.

Travel in avalanche terrain is not recommended. Safest travel on windward ridges and lower angle slopes without steeper terrain above.

Widespread natural or human triggered avalanches certain.

Extremely unstable slabs certain on most aspects and slope angles. Large, destructive avalanches possible. Large, destructive avalanches possible. 

Travel in avalanche terrain should be avoided and travel confined to low angle terrain well away from avalanche path run-outs.