Archived North Rockies Report 28 January 2016

[Comment]
This region has only a blog, not a daily advisory. This entry was the most recent one posted on
January 29 when there was a fatal incident.
[End Comment]

Avalanche Problems & Travel Advice:

The primary avalanche problem for this upcoming weekend is:

Persistent Slabs - on buried surface hoar

Travel Advice

    Limit your exposure to overhead hazard from slopes above. Simple, low angle terrain should 
	provide great riding this weekend.
	
	Manage your group so there’s only one person on a slope at a time. Ensure other groups in the 
	area don’t cut onto slopes above you.
	
	If you have the skills, pull out your shovel and investigate the layering before riding a slope. 
	If you find one of those pesky persistent weak layers, it’s weighty evidence that there’s a 
	problem. If you don’t find the layer, a question remains whether it’s really not there or if you 
	just looked in the wrong spot. Hmmm, now what do you do???

Weather Recap & Current Snowpack

The past week was warm with treeline temperatures a few degrees on either side of freezing. It was 
also stormy with new snow accumulations of 30 to 50 cm of recent snow. Despite the new snow, total 
snowpack depths may not have changed much due to rapid settling (compression) with the warm 
temperatures.

Throughout the region storm slabs and wind slabs developed in the surface layers; these weaknesses 
should gain strength relatively quickly. Areas like Pine Pass, Torpy, Renshaw, and possibly 
Tumbler Ridge have buried surface hoar in the mid-pack; my sense is this is a classic layer for 
concern. Sadly, there was a fatal avalanche in the Torpy region on Saturday Jan 25 which likely 
triggered this layer. Otherwise the snowpack appears to get harder with increasing depth which 
generally is a good thing (aka stable layering).

Weather Forecast

The pattern is set to change starting Friday when the warm & moist SW flow shifts to the west or 
even northwest flow by the weekend. That means cooling temperatures and an end to storm-snow 
accumulations. For the weekend, and early next week (say till Wednesday Feb 02), that northwest 
flow means temperatures around -10 C, a mix of sun & clouds, and light snowfall (especially on 
the Alberta side of the Rockies) of no more than 5 to 10 cm on any given day. 

Looking Forward to the Weekend

Cooler temperatures and no new storm-snow accumulations is good news for the snowpack, especially 
after a couple of days of adjustment. Assuming the wind remains light, surface layers should gain 
strength fairly quickly. Small amounts of blower pow should make for great riding.

If the wind freshens to where it can transport recent snow into drifts on lee or cross-loaded 
terrain (behind ridges, ribs, in gulleys, or behind any terrain feature that acts as a snow 
fence at treeline and alpine elevations) localized wind slabs become a concern.

Where buried surface hoar (a persistent weak-layer) was reported within the top 100 cm of the 
snowpack, the corresponding avalanche problem is going to persist. It won’t miraculously heal 
with a few days of cooler and drier weather. Surface hoar problems seem to be consistently 
reported from places like Pine Pass, Torpy, Renshaw, and possibly Tumbler Ridge riding area. 
It seems to be less of a problem in deep snow areas like Kakwa. 

ilya storm