Bollettino valanghe

Continental

Valdez Avalanche Center
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2 · Moderato
Limite del bosco
1 · Debole
Sotto il limite
2 · Moderato
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In sintesi

The avalanche hazard is Moderate at low elevations due to the possibility of wet loose activity, and at upper elevations due to the potential to encounter wind slab up to 1 foot in depth in isolated areas.  The hazard is low at mid elevations where a stable snowpack exists.

Public avalanche forecasts are issued Wednesday- Sunday at 8 am

Problemi valanghivi

  • Wind Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Isolated areas of windslab up to a foot thick may be encountered mostly at upper elevations today.  Observations throughout our forecast area from the last week have shown few signs of instability in most areas. The exception is small areas of instability where the wind has stiffened and deepened old storm snow.  These include slopes below high-elevation ridges in wind-channeled terrain or cross-loaded gullies. Watch for signs of wind-loaded snow such as fresh wind lips, and areas that have a pillowed look or rippled texture especially if you travel in complex or unfamiliar terrain. 

    For better stability and riding quality, seek out areas that are unaffected by wind, luckily these areas are pretty easy to find right now.

     

    Signs of instability within a small pocket of wind loaded snow. Loveland Basin 2/19

    Photo: Gareth Brown

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–2

    Small wet loose avalanches will be possible at elevations below 1500 feet, where warm temperatures are expected to occur today.  Overcast skies are expected, but if the sun does pop out, wet, loose activity will be more pronounced on solar aspects.  If you travel at lower elevations pay attention to how temperature is affecting the upper snowpack. In areas where snow becomes sticky and produces rollerballs, the wet loose hazard is increasing. 

     Observations from Keystone Canyon on Wednesday showed only a very thin melt-freeze crust at the surface with ~6 inches of dry snow beneath.  If this crust is able to break down during the heat of the day, dry snow will become susceptible to wet loose activity.  Wet loose activity is expected to be confined to the 6-10" of settled new snow that has fallen over the last week.  

     When assessing wet loose hazards, it is essential to take the hazard in relation to the terrain you are exposing yourself to.  Are there terrain traps? Are there consequences if I were to be swept off my feet by even a small avalanche? 

    The size and shape of the terrain above you along with the amount of loose snow available to slide, directly correlates to the size of the wet loose activity that can occur. Terrain traps and exposure below you compound consequences.

Avalanche Discussion

Observed Avalanche Activity last 72 hours: 

Numerous small wet loose slides at low/mid elevation on the South side of Thompson Pass

For information about the previous Deep slab avalanche cycle, click the avalanches tab below the bottom line statement once you have entered the full forecast for a partial documentation of activity.

Three Pigs natural avalanche information click link here.

For a more detailed Keystone Canyon observation with full pit profile click link here.

Forecast Discussion:

Our area received a few small pulses of snow between 2/14-16.  Totals added up to 8-16" and has now settled down to 6-10" dependant on location and elevation.  This new snow accumulated on buried surface hoar up to 3k, with very developed grains between 1500'- 2500' depending upon location.  Despite the weak snow at the interface at specific elevations, shallow slabs (~6") have not yet created an issue except potentially for consequential low-elevation terrain.  Above 3k the new snow is well bonded to old wind-affected surfaces with a notable low amount of spatial variability. 

Benign weather with light winds and trace amounts of snowfall have typified the weather over the last few days and are expected to continue in the short term.  This has allowed a period of good stability with avalanche problems being minor wet loose activity at low elevations and small pockets of wind slab in isolated locations at upper elevations.  We are not currently tracking any persistent weak layers beneath the new/ old interface of 2/14 (hard wind affected snow).

Special note for Ice Fest:  At low elevations in Keystone Canyon there ~6 inches of dry snow above a rain crust from late January. Below this crust is a layer of facted snow.  These facets showed signs of propagation in ECT tests when isolated.  This has not been listed as a specific avalanche problem as it is unlikely for a person to cause the rain crust to fail on a slope of any reasonable size due to its connective strength.   There is a concern though, that this layer could produce human-triggered avalanches up to 1 foot in depth on steep unsupported slopes where the continuity of the rain crust could be compromised and act as a slab.

The deep slab avalanches that occurred in late January are now believed to be a dormant problem that will require a significant change in weather to reactivate.

 

Additional Information:

Active rockfall has been recently reported in Keystone Canyon.

A weather and snowpack season history is available by clicking on the Season Summary tab which is located below the bottom line statement once you have entered the full forecast.

Season Snowfall Data

Location 24 hour Snowfall Inches- 2/22 24 hour Snow Water Equivalent Inches Height of Snow February Snowfall Inches Season Total Snowfall Valdez   1    N/O    50     10      Thompson Pass    1    N/O   N/O    9    ~500 Nicks    0    0    136    6 N/O 46 Mile    0     0   22    4 N/O

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