[MCR] Ice Fall at Johnston Canyon

[Public Mountain Conditions Report]

To add to the recent list from Haffner and Evan-Thomas, this busy  
morning at Johnston Cyn we were treated to another reminder about the  
need for awareness of overhead ice hazard right now. In the canyon  
the sun is beginning to hit the upper sections of the climbing lines  
-- and the typically healthy curtain of hanging daggers right of the  
main falls -- just after 10am. I had just finished my briefing about  
where not to linger when a massive (i.e. 1000kg+) exclamation point  
detached itself from the highest hanging curtain and punctuated my  
sentence. Fortunately, at that moment, everyone was well away, so  
only my syntax was injured, but after the powder cloud and nearby  
strafing subsided, there were definitely a few other exclamations  
uttered....

For me, this event was just reinforcement of the fact that the recent  
wide temperature swings of calm bluebird days (-30C on the ground at  
1000 hrs, +3C at the lip at 1230 hrs) and the slight-but- 
strengthening wind-less inversion that's been happening are something  
to be reckoned with.

As some extra value, over these last few days I've been out, in  
addition to the am/pm temperature differential and the inversion, the  
solar effect of the late Feb sun has also been feeling significant.  
At 1300hrs, while the temperature in the creek was -10, it felt more  
like +5 in the sun at the tops of the climbs 30m higher. Screws at  
that point had a lifetime of about 15-20min before they were fully  
melted out.  So, it's a good time to start perfecting your V-threads.

Just stay out from under the icicles while you do it.

Carl Johnston
Yamnuska Mountain Adventures
RG, AAG
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