Boletín de aludes

Yukon

Feb 4 – 6, 2020Avalanche Canada
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Archivado · caducó 7 years ago

Peligro de aludes

Thu
Fri
Alta montaña
3 · Notable
Límite del bosque
3 · Notable
Bajo el límite
Sin grado

Lo esencial

With another storm on the horizon another round of wind slabs is likely in the making. Best riding will continue to be protected areas that aren't scoured, at lower elevations where there's visibility. Thanks everyone for your great sunnyweekend MIN posts! ilya

Problemas de aludes

  • Wind Slabs

    • Alta montaña
    • Límite del bosque
    • Bajo el límite del bosque
    Probabilidad
    Likely
    Tamaño
    1–2.5

    Fresh snow combined with strong winds have formed a widespread storm slab / wind slab problems. 

Avalanche Summary

Last weeks storm reports include wind-loading the Racine paths such that avalanche hazard (and avalanches) closed the highway. The MIN has photos of a size three natural avalanche on Log Cabin. Otherwise only a few reports of smaller wind slabs.

Confidence

Moderate - Uncertainty is due to the timing, track, & intensity of the incoming weather system.

Weather Forecast

The weekend clearing was short lived as there's another storm on the doorstep ....

Monday Overnight: Snow starting late in the day and intensifying overnight with 10 to 15 cm expected. Unsurprisingly it'll come with strong southwest winds and warming temperatures all the way to around -10 C. 

Tuesday: Very similar to Monday with another 10 cm of snow, strong southwest winds gradually easing, and slight warming to around -5 C.

Wednesday: Continued unsettled weather with more new snow, more moderate to strong southwest wind, and continued moderate temperatures around -5 C. 

Thursday: Mix of sun and clouds, flurries or light snow, temperatures start to cool.

Snowpack Summary

The wind has shifted direction several times the past week; however, wind transport was predominantly driven by the southwest wind: big pillows of wind slab formed on north and east facing features. As expected wind scoured slopes abound above treeline with sastrugi and variations on that theme. More surprising good powder and riding was found on lee or more wind protected / sheltered areas.

Snow depths at White Pass increased last week and have now settled in around 150 cm at our wind protected Fraser study plot. Deeper locations (higher terrain west of the highway) have more than 200 cm. It's reasonable to expect a thin snowpack composed mainly of sugary facets in the Wheaton Valley, and thinner wind-scoured alpine areas.

Here's a non-technical snowprofile from the Fraser study plot from the end of January.

Terrain and Travel

  • Expect slab conditions to change drastically as you move into wind exposed terrain.
  • If you are increasing your exposure to avalanche terrain, do it gradually as you gather information.
  • Watch for signs of instability like whumpfing, hollow sounds, shooting cracks or recent avalanches.
  • Back off if you encounter whumpfing, hollow sounds, or shooting cracks.

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