Bollettino valanghe

Continental

Valdez Avalanche Center
Vedi sulla mappa

Pericolo valanghe

Alta quota
3 · Marcato
Limite del bosco
3 · Marcato
Sotto il limite
3 · Marcato
Non aggiornato — questo bollettino è scaduto 2 years ago. Stai vedendo condizioni passate, non il bollettino in corso.

In sintesi

The avalanche hazard will begin as low today on all aspects and elevations.  As the sun begins to melt the surface of the snow the hazard will increase to Considerable.  Human triggered and natural wet loose avalanches will become likely during the heat of the day.

Today is the last day of public avalanche forecasts.  Thank you to everyone who contributed to and used the information provided by Valdez Avalanche Center this season.  We look forward to next season !!

Problemi valanghivi

  • Loose Wet

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    1–3

    Wet loose avalanches are once again today's primary avalanche concern.   The low temperature on Thompson Pass was 36° last night.  Nicks had a low of 34, while low elevations north of Thompson Pass did receive a solid refreeze.  Warmer overnight temperatures will allow for wet loose conditions to occur earlier in the day than what has occurred the last few days and may be more significant.  Steep slopes with wet snow at the surface will be capable of producing wet loose avalanches.  Avoid travelling on or spending time below steep terrain where more than 4 inches of the surface snow is wet.

     This type of avalanche starts small and slow but can quickly grow and become dangerous, potentially burying or sweeping a person away, especially in steep, rocky areas or near cliffs.

    Today’s avalanche risk starts low in the morning and increases with the sun's warmth, first on east-facing slopes and later moving to south and west-northwest aspects as the day progresses. A slope that is frozen and stable in the morning might not be safe in the afternoon. 

    To stay safe, be mindful of the sun's path and avoid steep sunny slopes during their warmest times. Always consider the terrain below you, avoiding areas that could amplify the consequences of an avalanche, like cliffs and gullies.

    (4/25/2024)

    Natural wet loose and wet slab avalanches on South Three Pigs

    Photo: Gareth Brown

  • Wet Slabs

    • Alta quota
    • Limite del bosco
    • Sotto il limite del bosco
    Probabilità
    Possible
    Dimensione
    2–3

    The degree of natural avalanche activity is increasing with each sunny day.  Above freezing temperatures overnight at elevation will likely continue the increase in activity that has been recently observed.  Several large natural wet slab releases have been noted on steep south faces over the last few days.   Daytime heat is slowly penetrating deeper into the snowpack with each diurnal cycle.  As this process continues wet slabs are expected to continue to release on steep south aspects and may begin to happen on other aspects.

    There is still a lot of snow mass in the mountains.  Daytime high and low temperatures have increased significantly over the last week.  This change puts stress on the snowpack.  The first signs of stress are in the form of wet loose activity that occurs at the surface.  As heat can penetrate deeper into the snowpack it becomes more likely for stress to be relieved in the form of wet slabs as old interfaces deeper in the snowpack that were dormant become lubricated by meltwater and reactivate.  Identifying which slopes are prone to this kind of release is difficult.  What we can do is recognize that this type of activity will be most likely to occur during the heat of the day when more than 6 inches of the surface is wet and the snowpack begins to be unsupportable on foot.  Avoid steep terrain when these conditions are present.

    (4/24/2024)

    Wet slab release near the toe of the Worthington Glacier

    Photo: Gareth Brown

Avalanche Discussion

RECENT AVALANCHE ACTIVITY:  

Last 72 hours: Large wet loose and wet slab natural avalanche activity has been observed on steep south facing terrain, with notable activity on Three Pigs. 

DISCUSSION:

2 weeks of dry and sunny weather have allowed our snowpack to transition to spring conditions with diurnal swings in the hazard level dictated by solar input.  Snowpack stability will vary significantly depending on the time of day and aspect.  In areas where the snow surface is frozen, the hazard is low.  As the sun warms and melts the surface the hazard will increase to moderate and then Considerable depending upon the depth of wet snow that exists.

 The daily swing in avalanche hazard is currently very predictable making mitigation of this hazard far more straightforward than avoiding other avalanche problems.  The main hazard for users will be exposing themselves to steep terrain that is baking in the sun.  Keep in mind that triggering wet loose activity is not the only concern, but includes staying out of the way of the natural shedding process that occurs each day.  Avoid grouping up and spending time beneath large sunny slopes especially ones with cornices.

Wet slab activity is becoming more likely during the heat of the day as heat is beginning to penetrate deeper into the snowpack.  Wet slab releases involve far more mass than a typical wet loose release making them far more dangerous.

Additional Concerns:

This is the time of year when cornices begin to fail.  You can significantly reduce your overall exposure in the mountains this time of year by avoiding traveling on top of or under cornices.

Glide crack releases have been observed on the southern aspects of Town Mountain lately.  Glide cracks exist in isolated areas and will be a hazard throughout the season until they fail.  Avoid exposure to glide cracks.

Valdez season snowfall: 293  inches

Valdez April snowfall: 11 inches

Valdez height of snowpack: 53 inches

Thompson Pass season snowfall: 698 inches as of 4/5

46 mile height of snowpack: 48 inches

 

Regioni coperte