[MCR] South Coast conditions

[Public Mountain Conditions Report]

Two ACMG Ski Guide exams visited several locations in the Cayoosh  
Summit/Joffre area of the Duffy Lake road, Mystery Creek and the  
Spearhead traverse between April 16-24. Tours ranged in elevation from  
~1300m to ~2500m and all aspects were skied.

The beginning of the week saw weak to non-existant overnight freezes  
and an isothermal snowpack extending from roadside elevations (~1300m)  
up to treeline.  During the days, weak surface crusts formed overnight  
would breakdown quickly and avalanche hazard increased rapidly with  
daytime heating and solar input.  Weak and newly enlarged cornices  
(from a major storm event the previous week) were our major concern--  
from exposure to the cornices themselves and as triggers for slopes  
below.

Wednesday, April 22nd saw a major rainfall event with rain extending  
to 1800/2000m in most locations.  This saturated the upper 50cm of the  
snowpack and produced many loose snow avalanches on all aspects from  
below treeline to ridgetop.  A major natural avalanche on Chipmunk  
Mtn, (sz 4 with a 1-2m deep crownline extending 550m across) occurred  
during this period.

Thursday and Friday (22nd and 23rd) saw stronger overnight freezes and  
generally cooler temperatures during the days.  This resulted in the  
development of a 5-10cm thick crust layer at the snow surface which  
helped stabilize the snowpack.  However, weak and saturated snow still  
exists below this crust and when temperatures rise and solar input  
increases, expect this surface crust to weaken and stability to  
decrease rapidly.

Cornices remain a major concern, especially when exposed to sun and  
rising daytime temperature.  The major avalanche that occurred during  
the rain event also indicates that deep instabilities in the snowpack  
can "wake up" during periods of higher freezing levels and increased  
precipitation (rain).

Excellent spring skiing was found, specially after daytime warming  
softened the surface layers but hard boiler plate skiing was also  
experienced on North aspects above 2000m. The Singing Pass trail ski  
out was still passable as of Friday April 23 but is deteriorating  
quickly at lower elevations.

Thanks to all the candidates for their input.

Sylvain Hebert
ACMG Ski Guide
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