Lawinenlagebericht

Crowsnest North

Apr 12 – 13, 2023Avalanche Canada
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Lawinengefahr

Fri
Sat
Hochgebirge
2 · Mässig
Waldgrenze
1 · Gering
Unterhalb
1 · Gering
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Kernpunkte

As the freezing level falls overnight and then warms during the afternoon, you will find that conditions change rapidly through the day. Be cognizant that daytime warming can rapidly destabilize the upper snowpack.

Lawinenprobleme

  • Storm Slabs

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    Tuesday snowfall overlies a warm and moist surface and is likely to be bonding well. Expect during periods of daytime warming potential for increased sensitivity to triggering will exist as the storm slab settles rapidly.

    Past strong southwest alpine wind could be stripping ridges down to rock, or rapidly loading leeward terrain.

    Use extra caution around ridgecrests, rolls, and on convex slopes. Retreat to mellower terrain if you find signs of instability like shooting cracks, whumpfs, or recent avalanches.

  • Loose Wet

    • Hochgebirge
    • Waldgrenze
    • Unterhalb der Waldgrenze
    Wahrscheinlichkeit
    Likely
    Größe
    1–2

    Past moderate rainfall up to 2500 m, has unconsolidated the upper snowpack. Expect a good recovery and refreeze overnight, however the expected daytime warming will continue to support loose wet avalanches as a problem at lower elevations and especially on south aspect terrain when the sun makes an appearance.

    Watch for signs of a loose, wet snowpack, like snow pinwheeling or snowballing down the slope, or surface snow that looks and feels like a slurpy.

Avalanche Summary

On Tuesday, field teams reported observing a number of large (size 2) wet loose avalanches that started in steeper terrain and ran down onto 30 degree slopes but not running full path.

On Monday in neighboring Waterton National Park, numerous loose wet avalanches up to size 2.5 were reported on all aspects and elevations during the warm, wet storm.

If you have any observations from this region, let us know what you are seeing by submitting a report to the Mountain Information Network.

Confidence

Moderate

Snowpack Summary

In the alpine and around treeline, 5-10 cm of new snow covers rain soaked surfaces. These surfaces are beginning to refreeze with the overnight cooling .Prior to the weekend storm, dry snow only remained on shaded (northerly) slopes.

The mid snowpack is generally settled and strong at treeline and above.

A melt-freeze crust that was buried in mid January can be found 60 to 100 cm below the snow surface.

A weak layer of large, sugary crystals persists at the base of the snowpack. This layer has not produced recent avalanche activity in this area, but professionals continue to monitor for signs of it becoming active.

Weather Summary

Overnight cooling followed by afternoon rising freezing levels and warming is likely to unconsolidated and rapidly settle the upper snowpack especially on south aspect terrain when the sun appears. Prepare to continually evaluate the conditions, and change plans as necessary.

Wednesday Night

Cloudy. Trace amounts of snow. Freezing level descending to 1000m, Alpine temperature low of -9°C. Moderate to strong southwest ridgetop wind.

Thursday

Clearing with some cloud. 1-5 cm of snow. Freezing level rising to 1700m, Alpine temperature low of 0°C. Light southwest ridgetop wind.

Friday

Cloudy. 1 to 5cm of snow. Freezing level rising to 1800m, Alpine temperature low of 1°C. Light Northeast ridgetop wind.

Saturday

Mostly clear with some afternoon clouds, no new precipitation. Freezing level rising to 2000m, Alpine temperature low of 2°C. Light to moderate west ridgetop wind.

More details can be found in the Mountain Weather Forecast.

Terrain and Travel Advice

  • Continue to make conservative terrain choices while the storm snow settles and stabilizes.
  • Be alert to conditions that change with aspect and elevation.
  • Be alert to conditions that change throughout the day.
  • Watch for unstable snow on specific terrain features, especially when the snow is moist or wet.
  • The more the snow feels like a slurpy, the more likely loose wet avalanches will become.

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