[MCR] Persistent Weak Layers 2007-2008

With assistance from the CAC forecasting team, I have prepared an article on this year's persistent weak layers that exist in many areas of the western Canadian mountains. The paper can be found here:  http://www.avalancheinfo.net/Media/Persistent%20Weak%20Layers%20and%20the%20Winter%20of%202007-08.pdf

Persistent weak layers that create a deep slab instability are a complex issue that is difficult to describe and discuss in the limited space of an avalanche bulletin. I hope this article will serve as a valuable reference for anyone planning activities in BC or Alberta this winter.

Karl Klassen
Mountain Guide
1735 Westerburg Road
Revelstoke,  BC
Canada
V0E 2S1
250-837-3733
kklassen@rctvonline.net

[MCR] Purcell Mountains, Powder Creek Jan 20-27

Spent the last seven days, Jan 20 – 27, ski touring at Powder Creek Lodge in the Purcell range near Kaslo BC.

 

The first six days of the tour were clear cold and calm, overnight low temps  –20 degrees, daily highs –8. Previous NE winds had created widespread, variably distributed surface slab development in open areas from below treeline to the alpine. We had best luck with ski quality on north and west slopes treeline and below. The alpine zone was super variable ski quality.

 

Snowpack and Avalanches:  The cold temps made for good facetted powder where not wind affected.

The windslabs, which ranged from soft (4F) to hard (P),  5 – 30cm thick, settled and bonded well as the week progressed, giving a couple very small results with ski cutting. No significant cracking, propogating, or whumphing. The early December crust is buried down 130cm at 1900m, hard to no results in snowpack tests. The crust does not exist above this elevation in the Powder creek tenure, though the interface from this date is discernible as a layer of rounding facets. One natural sz 2.5 avalanche occurred mid week on this layer, over a metre deep and 200m wide, on a steep sunny SW facing bowl at 2100m. On Jan 25 there was a sz 2 natural 50cm crown, out of a steep chute, also on a solar aspect at 2100m.

  With this snowpack and stable weather we were able to gain confidence throughout the week, attaining some great alpine ski touring objectives with a thought to minimizing our exposure to over head cornice hazard, solar slopes in the PM, and really rowdy unsupported terrain.

 

The thing now is that last night we received 20cm of low density snow, and more snow is forecast. This sits on a surface hoar layer that formed this week, all aspects and elevations, average size 5mm. The SH sits on a suncrust on steep south slopes.

 This newly buried layer is sure to be a concern when the fresh snow on top settles out and densifies, or the wind creates slab conditions.

 This synopsis will apply to the greater Kootenay Boundary region as the weather patterns have been similar over the area.

 

 Joel McBurney, SG

 Nelson BC

 

 

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[MCR] (no subject)

Selkirk Mountains - Rogers Pass - Mt. Sir Donald basin - Jan.25-08

 

Skied 3 days in the Pass this week today being the latest.

 

Biggest observation is the variability in the current snow surface – I was finding variable wind slabs in the alpine or 20 cm. of loose surface snow (faceted) depending on exposure to wind, some places were totally sheltered and provided great skiing – today there were sun crusts on steeper south through southwest aspects but not on the lower inclined slopes.

 

Then there is the surface hoar – inevitable after so many clear nights – observed 5-10mm. crystals in the valley bottom diminishing to 3-5mm. or less once you reached treeline – on the steep southerly aspects the surface hoar is sitting on the crust – not a great combination once loaded with new snow.

 

As well there was a delicate layer forming on the surface, comprised of large new snowflakes (stellars) that were falling out of the broken skies.

 

Also of note is the number of skiers in the Pass – so lots of lines have been skied over the last week. By the way you could see that surface hoar had grown in some of the old tracks.

 

No recent Avalanche activity everything we saw looked to be several days old.

 

The snow in the forecast will for sure be falling on a poor interface so I know I will be tip toeing around for a while if we receive any significant amount of snow.

 

Safe Travels

 

Scott Davis

Best Ever Adventures

E-mail: sdavis@alpineadventure.com

Check out the website: www.alpineadventure.com

(250)837-9630

Box 2795 Revelstoke, B.C.

V0E 2S0

 

[MCR] Pilsner avalanche

Hello

 

Driving by Field today and noticed a recent slab that avalanched on the approach to Pilsner Pillar.  It was a size 1.5 and would have been nasty as it went down through the trees.  I couldn't see any tracks from climbers (possibly animal triggered??) and it was on a bit of a steeper roll (left side, halfway between the top of the trees and the base of the route).  It looked like the crown was quite deep (60-90cms) and it slid sometime in the last 48 hours.  The slopes above the route looked quite loaded.

 

Take care out there..

 

Mike Stuart
ACMG Alpine Guide

[MCR] Urs Hole Avalanche

Noticed a fresh avalanche today out of the start zone above Urs Hole on
Cascade. It was a Class 2.5 slab that looks like it ran over the climb. It
was a clear sunny day with cool valley bottom temperatures, but the
temperatures at higher elevations were much warmer. Likely the trigger was
due to solar warming. Something to think about right now when choosing
routes with sunny start zones above them.

Brian Webster
UIAGM Mountain Guide

_______________________________________________
These observations and opinions are those of the person who submitted them. The ACMG and its members take no responsibility for errors, omissions, or lapses in continuity. Conditions differ greatly over time and space due to the variable nature of mountain weather and terrain. Application of this information provides no guarantee of increased safety. Do not use the Mountain Conditions Report as the sole factor in planning trips or making decisions in the field.
Please check out http://acmg.ca/mcr for more information.

[MCR] Coast Range - Cereise Ck.

Up at Cereise Ck yesterday.

 

Brrrrr

 

Cold temps hovering around -15C.

Strong outflow winds from the E and NE most of the day producing windslabs in alpine and open treeline features. Due to strength of winds, windslabs forming lower in the slope that you would expect.

I would suggest being very cautious for the next few days until these windslabs settle out.

 

The top 20-30 cm were becoming more facetted with these cool air temps. Whenever this clear spell ends, and the next snowfall comes, I expect this layer will be cause for concern.

Suncrust and windcrust managing to limit good skiing options, but we found excellent mid-boot-high pow in shallow trough features just above T/L and boot-top in tree glades.

Ran into another group that skied a higher gulley feature off Joffre ridge - apparently terrible skiing!

 

Brian Gould
Mountain Guide

[MCR] Pretty Nuts, Jan 20th

Warmer over in the Kicking Horse yesterday. Pretty Nuts in fine shape
although we didn't climb the WI 4 option on the left on pitch 2,
looked like small pillars and sporty. Seems like the place to park is
at the Golden end of the massive concrete retaining wall that starts
100 meters Goldenwards from Pretty Nuts, a small pull out on the
riverside of the highway there. We parked at the chain-up area 300
meters farther away and closer to Golden (just to the east of Lady
Killer) and on the riverside of the highway.

Happy trails

Barry Blanchard
Mountain Guide
Yamnuska Mountain Adventures
_______________________________________________
These observations and opinions are those of the person who submitted them. The ACMG and its members take no responsibility for errors, omissions, or lapses in continuity. Conditions differ greatly over time and space due to the variable nature of mountain weather and terrain. Application of this information provides no guarantee of increased safety. Do not use the Mountain Conditions Report as the sole factor in planning trips or making decisions in the field.
Please check out http://acmg.ca/mcr for more information.

[MCR] Selkirk Lodge

Just Got back from a week of guiding at Selkirk lodge with Robson Gmoser.  Lots of snow up there.   250 to 300 cm at tree line and about 350 to 400 cm on the glaciers.  It snowed about 60 cm during the week.

Our Main concern was the Strong winds up high which formed Wind Slab.  The skiing was excellent once you got down 300 feet from  the ridge tops.  We had no concern of deep instability because there was so much snow.  We still stayed away from big Alpine features, and anywhere where it looked shallow.

Be safe!

Marco Delesalle
IFMGA Mountain Guide

[MCR] Fairy Meadows Hut, Adamant Range, Northern Selkirks

Just back from 8 days of great ski touring at the Fairy Meadows Hut with James Vickers!

 

Travel was good with about 200cm at treeline, and from 240cm to over 300cm on most of the glaciers.  The largest crevasses were still thinly bridged and wind scoured areas were also quite thin,  so we took fairly conservative lines while skiing on the glaciers as well as traveling roped up a fair bit.

 

In terms of avalanches we had about 60cm of new snow through the week accompanied by some high winds at times.  Our main concerns were wind slabs in lee features and on steep rolls.  Below the wind slabs the snow pack was quite strong with no major concerns for deeper layers as of last week.  Some weak areas around rocky outcrops and moraines were also avoided.

 

A great place to spend a week hunting powder!

Cheers, Conrad Janzen
IFMGA Mountain Guide
403.678.8336(cell)// 403.760.0887(home)

A person should have wings to carry them where their dreams go, but sometimes a pair of skis makes a good substitute. -Hans Gmoser-

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[MCR] Valkyr addition

I should add that the Valkyr Range is south of Nakusp, directly above the town of Fauquier and the Lower Arrow Lake. More information on conditions and weather can be found at www.wisegoat.ca

Mark Klassen

Mountain Guide

[MCR] Kootenays - Valkyr Range

The last 5 days have been spent in the Valkyr range of the southern Selkirks. 

Light snowfalls, light to moderate W-NW winds and temps of -6 to -18.

We have been on the windward side of the range and as such the snowpack depth has been variable, from 120-200 cm. The main layer of concern is a thick layer of weak 4 Finger facets lying atop a Pencil to Knife resistance ice crust on the ground. A thick mid-pack Pencil resistance slab lies above the facets. The Dec 5 layer is not very evident here, and the significant shears we have seen have been failing in the aforementioned facets, moderate to hard compression tests with a sudden compression fracture character. However, there have been no natural avalanches noted and no whumpfing or cracking.

There is also considerable wind effect in the alpine and wind slabs are a concern at higher elevations.

We are staying on small features, supported terrain, and staying away from starting points in thin spots.

We are rating danger as Moderate at all elevations, with a concern of high consequences if an avalanche fails in the facet layer near ground.

Mark Klassen

Mountain Guide

[MCR] curtain call picture jan 17

Picture of curtain call Jan 17, 2008.

 

Garth Lemke

ACMG ass. ski guide

JNP Public Safety Warden

[MCR] Observation sub peak Mon, Jan 14

Third day of an Avalanche Safety Training II course. We toured up to
the 8000 foot level on the northern Observation Sub Peak (Alpine Ski
Tours in the Canadian Rockies by Chic Scott guidebook page 95): Temp
of -2 C at Bow Summit @ 10:30. -3 C @ 7184 feet @ 12:00. Compression
tests of moderate (CTM5) on a clean planar shear 20 cm down at the
interface of 1f and 4f layers, SW aspect, 20 degree slope, height of
the snowpack was 86 cm. Moderate SE winds scouring and transporting
snow at treeline. We skied 20 degree slopes below treeline.

Barry Blanchard
Mountain Guide
Yamnuska Mountain Adventures
_______________________________________________
These observations and opinions are those of the person who submitted them. The ACMG and its members take no responsibility for errors, omissions, or lapses in continuity. Conditions differ greatly over time and space due to the variable nature of mountain weather and terrain. Application of this information provides no guarantee of increased safety. Do not use the Mountain Conditions Report as the sole factor in planning trips or making decisions in the field.
Please check out http://acmg.ca/mcr for more information.

[MCR] Gibraltar Wall, Jan 14

Climbed at Gibraltar wall near Canal Flats today. Overall a little thinner than normal, but still plenty of options on good ice. The first pitch left side is not in, second pitch left side is typically thin and delicate looking, upper left side filled out and blue. We ascended the middle line, good climbing and gear up to WI 4.

 Mostly an overcast day with temps hovering around freezing, above zero when the sun would peek out.

 Snowing heavily from Creston to Nelson on the PM drive home.

 

 Joel McBurney  SG

 

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[MCR] Rockies Ice climbing conditions

We just finished a 4 day ice climbing school (Jan 9-12) and offer these observations:

- Balfour Wall - good shape, good toproping.
- Louise Falls is in good shape and the pillar is perhaps a bit easier than usual.
- Carlsberg in classic grade 5 conditions and quite wet at the bottom.
- Guiness Gully thin and barely protectable on pitch one still, but the climbing is not too hard.
- Moonlight/Snowline in good shape with screws the whole way.  2 low for 0 looks awesome but hard to protect.
- Arterial Spurt thin grade 3 with stubby screws to protect 5 thin, rambly pitches.
- Ghost River - the driving was fine as someone else has dug through the drifts already.  Valley of the Birds was excellent with all routes in good shape up to the Eagle.  Also, Weathering Heights in good shape and the other routes in the Planters Valley still well formed.

Other than in Field we stayed away from avalanche hazard and so didn't have to think about it too much.  Mostly when we did think about it we focused on what big slopes had already avalanched (or not), and what faced into the sun and would warm up through the day.  We did not expect large natural avalanches but it seems like with some minor change in weather (warmer, more snow, wind) we might see this start again.  None of us were keen to cross large, steep slopes and human triggering can be expected.

In Field we are generally wary of warmth and/or rainfall to trigger avalanches in those gullies and this was not the case yesterday (Sat).

Grant Statham, Percy Woods, Brian Webster
Mountain Guides

[MCR] Icefall lodge area, Jan 6-12, 2008

Just back from a week at the icefall lodge area in the western
Rockies, west of the Lyells. We arrived at an interesting time on
January 6th just after a cycle which seemed to show some results in
isolated areas viewed from flight in. Most of the activity was at
lower elevations with some isolated paths running to valley bottom in
the drainage of the hut. Our tests showed some moderate tests in the
upper pack which tightened up over the week. These were mostly in the
upper 40cm of the snow pack
Though visibility wasn't great all week we did not observe any slabs
activity in any of our travels on any adjacent slopes. We were pretty
cautious over the week not really pushing the terrain and using safe
travel. In shallow areas faceting was evident with one settlement
noted on a SE aspect near some rocks.
The snowpack at 1900 metres at the lodge was 160cm. We had about
10-15cm over the week with almost no wind affect anywhere. the
temperatures were very steady all week at around -10 to -15 with
little to no sun affect over the days. Some sluffing on steep terrain
was noted from some low density snow, and in the top 10-15cm, mostly
the last few days
Things would have been much different if we had any wind!.
See reports over the last week it seems like we were in a pretty
sheltered little part of the mountains.
Peter Amann

Peter Amann
Mountain Guiding
Box 1495, Jasper AB, T0E 1E0
780 852 3237
cell 780 931 2521
www.incentre.net/pamann/
pamann@incentre.net

_______________________________________________
These observations and opinions are those of the person who submitted them. The ACMG and its members take no responsibility for errors, omissions, or lapses in continuity. Conditions differ greatly over time and space due to the variable nature of mountain weather and terrain. Application of this information provides no guarantee of increased safety. Do not use the Mountain Conditions Report as the sole factor in planning trips or making decisions in the field.
Please check out http://acmg.ca/mcr for more information.

[MCR] Rogers Pass - Bonney Trees

Skied in the Loop Brook/Bonney Trees area today.

Overcast. Nil precip. -11 and calm at midday at 2050 m. It was windy on the peaks and cliffs of Swanzy and Bonney though, with snow transport up there. One rumble was heard, it could have been an icefall, cornice fall or avalanche but we couldn't see anything moving.

The Dec 5 crust was felt by probing, 80 cm down at 1600 m in the forest. At 1800 m we couldn't feel the crust anymore in a 250 cm snowpack. No wind effect in the moraines or on the glacier. It seemed to us that the Dec 5 crust is very elevation dependent in Rogers Pass and this has been confirmed in discussion with other professionals in the area. It seems to be mostly a below treeline issue here.

It has felt a little bit like the eye of the storm the past few days in Rogers Pass, just good skiing with minimal snow stability concerns, while everywhere around us it seemed like the world was falling down with recent reports of large avalanches in the Rockies, Kootenays, Okanagan and Purcells. Mostly it seemed to come down to terrain choice for us. We originally planned on skiing in the Rockies but because of the poor snowpack decided to go to the Pass instead. Then we picked areas that were sheltered from recent winds to avoid the reported wind slabs. Then on our runs we skied lines that had some steepness but were a series of short, well supported slopes and steered clear of  locally thin areas. With conditions the way they are it seemed to be a time to ski standard "classic" lines and refrain from "exploring" too much.

Keep them slippery side down!

Mark Klassen

Mountain Guide

[MCR] Cascade Avalanche

I was in the Cascade Waterfall area near Banff today and witnessed a
very large avalanche come pouring out of the bowl above the route.

This, in combination with observations made today by other
professionals suggest that the Rocky's snowpack is exceptionally
delicate right now. I'd give any avalanche terrain a very wide berth
and let things settle our for a bit before climbing or skiing near
avalanche prone slopes.

Heads up out there.

--
Matt Mueller
ACMG Assistant Alpine Guide
_______________________________________________
These observations and opinions are those of the person who submitted them. The ACMG and its members take no responsibility for errors, omissions, or lapses in continuity. Conditions differ greatly over time and space due to the variable nature of mountain weather and terrain. Application of this information provides no guarantee of increased safety. Do not use the Mountain Conditions Report as the sole factor in planning trips or making decisions in the field.
Please check out http://acmg.ca/mcr for more information.

[MCR] Rogers Pass - Hermit

Skied in the Hermit today, January 7.

We saw a well settled snowpack in the area we were in. We probed at 2000m and couldn't feel
the Dec 5 crust, but did feel a slight weakness at 120 cm down in a 200cm deep snowpack. Digging
at 2200 m in a morainal feature (our high point) found 165 cm, the upper snowpack settling well,
Fist resistance at the top slowly strengthening to 1 Finger 80 cm down. Then there was a 3cm layer
of 1 Finger minus snow with larger grains (this must be the Dec 5 layer) before the snow became 1
Finger plus. No significant weak layers were felt with probing below this. No shears were found,
except for some resistant ones near the surface in the soft snow.

No cracking or whumpfing. There was what looked like a recent small size 2 off steep cliffs,
possible cornice triggered. It did not run far downslope.

There has been wind effect on the ridges and I can see this being a problem if these slabs were
overtop the low density recent storm snow. These areas seemed pretty obvious to us and easy to
avoid in this sheltered basin.

Mark Klassen
IFMGA/ACMG Mountain Guide

_______________________________________________
These observations and opinions are those of the person who submitted them. The ACMG and its members take no responsibility for errors, omissions, or lapses in continuity. Conditions differ greatly over time and space due to the variable nature of mountain weather and terrain. Application of this information provides no guarantee of increased safety. Do not use the Mountain Conditions Report as the sole factor in planning trips or making decisions in the field.
Please check out http://acmg.ca/mcr for more information.

[MCR] Anniversary Glacier Avalanche

I was skiing in the Cerise Creek drainage this weekend and observed a large natural avalanche worth noting. The East ridge of Matier above the Anniversary Glacier has avalanched and has run the full length of the valley below the glacier to end approximately 500 meters beyond the toe of the moraines. Debris has crossed Cerise Creek and removed a large swath of the 2nd generation trees on the east side of the creek, then turned the corner and ran down Cerise creek for another 100 meters. At least 300-400 meters of the standard approach to Keith's Hut is under 1 to 3+ meters of debris, including about a 200 meter section of Cerise Creek. Limited observations of the fracture line show it right at ridge top and it appears to be 3-4 meters in depth, possibly triggered by cornice failure during the recent high winds. There also appears to be a significant fracture line and avalanche on the moraine/boulder slopes underneath Joffre, most likely triggered by the impact of the first avalanche off of the East Ridge of Matier.  I could not see the middle steeper section of the Anniversary to see if it had slid as well.

 

I was in the parking lot at 0930 on Saturday Jan. 5th and heard a large event, but with poor visibility could not be sure if it was a large wind gust or an avalanche. When we reached the debris at noon there were a large amount of branches on the snow surface with little snow cover despite heavy snowfall, so I am fairly certain it ran at around 0930 that morning. Luckily there were no people on the approach at the time, though it is a very sobering sight to see such a commonly traveled route under so much debris. A good reminder to always question your choice of route, and what you are exposed to at that time, regardless of how "common" the route is.

 

Brian Jones

Mountain Guide

www.themountainschool.com

[MCR] Pemberton Area, Coast Mountains

I was skiing East of Mt. Curry above Pemberton today.  We found that the Dec 3/4th  layer got active mid storm probably yesterday and triggered many slab avalanches to size 2.5.  Many North facing rolls and steeper faces in the upper Tree Line slid.

The one fracture line I checked out was 130 - 170 cm deep. This slab slid 10 cm above the December ice layer in a layer of old facets. 

We did not see cracking or hear any sounds that would indicate further instabilities during our runs or during some ski cutting. But the presence of all these slides was easily enough to generally keep us off steeper angled terrain. We did not see fracture lines from slab avalanche activity in the Alpine or  Below Treeline but our observations where limited to one drainage and hampered by lots of cloud. About 1.2 meters snow fell (at tree line) during the last storm all of F to 4F density.

The skiing quality was excellent.

 

Dave Sarkany

Ski Guide

[MCR] Selkirk Mountains - Revelstoke area - Jan.4-08

What a difference a day makes – all that low density snow that Mark Klassen reported has now seen an increase in humidity and rising freezing levels as well as strong winds at treeline and Alpine – in other words things were much slabbier out there. There were two skier triggered size 2 slabs off the north side of Mt. Mackenzie (the backside of Revelstoke’s new ski hill) – they were triggered from very steep and obviously wind loaded terrain – in other words not surprising at all.

 

Even though the snow was slabby it didn’t react to skiers in moderate terrain – I steered clear of any convex features.

 

Also of note is all this wind has formed some fairly large cornices for this early in the season.

 

Snowing again this evening in Revelstoke – borderline rain.

 

Cheers

 

Scott Davis

Mountain Guide

[MCR] Rogers Pass area

Spent Jan 2 and 3 in the Rogers Pass area. We skied Corbin Pass
(treeline S aspect) and McGill Shoulder (treeline W aspect). Max
elevation was 2100m.

Up to 10 cm low density snow fell during the 2 days. Max temps of
about -2. Light winds not transporting snow.

At Corbin there was up to 120cm of Fist resistance gradually
stiffening to Pencil resistance snow atop a few cm of 1 Finger
resistance rounding facets; this combination lay atop the December 5
crust which was also 1 Finger and had facetted but had larger grains
than the layer above. Some minor wind effect at ridgeline on McGill
shoulder but no real slabbing was noted once we dropped into our line.

The November crust was alive and well at the base of the snowpack at
Corbin, 50 cm of facetting crust lying on the ground.

We could not find any shears in 2 test profiles in the Corbin area.
No cracking or whumpfing and no recent avalanches observed.

We skied treeline like it was Moderate danger, mostly due to feeling
out of touch with the mountains after a week of eating and lazing on
the couch. We limited our exposure to large features and skied one at
a time when we were close under the bowl on McGill (we avoided skiing
in the bowl). Below Treeline felt like it was Low.

Mark Klassen
Mountain Guide

_______________________________________________
These observations and opinions are those of the person who submitted them. The ACMG and its members take no responsibility for errors, omissions, or lapses in continuity. Conditions differ greatly over time and space due to the variable nature of mountain weather and terrain. Application of this information provides no guarantee of increased safety. Do not use the Mountain Conditions Report as the sole factor in planning trips or making decisions in the field.
Please check out http://acmg.ca/mcr for more information.

[MCR] Icefields Parkway snowpack

Hello Everyone,

 

    I went ski-touring with two clients up towards Crowfoot Glacier,  via the Bow Hut approach canyon on Dec 30th. We dug a test pit on a West aspect at 2400m on a protected 30 degree slope in the trees below the moraines. It revealed a generally shallow (85cm) weak snowpack with an easy shear down 50cm on mature facets.

 

 Today Steve Holeczi, Tim Haggarty and I went skiing in the Hector Lake area ( about 10km SE of the previous location). We dug a test pit on a Southwest aspect at 2200m on a protected 33 degree slope. The snowpack here was 135cm average depth. The interface down 50cm was still visible although not as weak at this location. However we got a clean shear (SP) down a 100cm on another weak faceted layer. We were able to keep  our skiing to smaller features on supported slopes.

 

 

  The great snowpack of the 2006/2007 winter is but a memory now.  In the areas  I've skied this season,  Selkirks, Purcells  and Rockies, it seems to be a highly variable colder snowpack with persistent weaknesses. 

 

Its a good winter to use your skills,  and be highly aware of the integrity of the snowpack you are travelling on,  and the terrain on which you apply it. 

 

Have a fun and safe winter,

 

Andrew Langsford

Alpine Guide/Asst. Ski Guide

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