Friday-Monday 4/14-4/17

Issued: Fri, Apr 14, 2017 at 8AM

Expires: Mon, Apr 17, 2017

Tonight!!! April 14: VAC Full Moon Spring Fling FUNraiser with Acoustic Avalanche at the Tsaina Lodge.   Grab a date and come boogie! Fire dancing, DJ and raffle too!

Recent wind out of the NE has moved large amounts of loose snow and and formed fresh wind slabs on lee aspects terrain features….evaluate bonding and possible weak layers underneath.

Spring conditions are here with rising hazard in the afternoon! As the sun warms and weaken snow on steep southerly faces, plan your day appropriately….limiting exposure to avalanches from above.

Above 2,500ft Moderate

1,800 to 2,500ft Moderate

Below 1,800ft Moderate

Degrees of Avalanche Danger ?

1. Low
2. Moderate
3. Considerable
4. High
5. Extreme

Avalanche Danger Rose ?

Avalanche Problems ?

Problem Details

FRIDAY SATURDAY SUNDAY & MONDAY

DANGER SCALE

 

WET AVALANCHES:
Elevation:
   Below 5000′
Aspect:
 South, southeast, southwest
Terrain:
Steep terrain near rocks and vegetation.
Sensitivity:
   Touchy when warmed.
Distribution:
   Specific.
Likelihood (Human Triggered):
   Possible
Size:
  Small-Large
Danger Trend:
   Increasing quickly each day with warming temperatures, falling at night
Forecaster Confidence:
   Good

PERSISTENT SLAB:
Elevation:
  Above 2500′
Aspect:
 All
Terrain:
Slopes > 35*
Sensitivity:
   Stubborn on northerlies, Touchy when warmed by sun
Distribution:
   Widespread
Likelihood (Human Triggered):
   Possible
Size:
  Small – Large
Danger Trend:
   Decreasing
Forecaster Confidence:
   Fair

 

AVALANCHE PROBLEM SCALE DESCRIPTORS:

Sensitivity: Non-reactive, Stubborn, Responsive, Touchy
Distribution: Isolated, Specific, Widespread
Likelihood: Unlikely, Possible, Likely, Nearly Certain
Size: Small, Large, Very Large (size scale <here>)
Danger Trend: Increasing, Steady, Decreasing
Forecaster Confidence: Good, Fair, Poor

AVALANCHE PROBLEM TOOLBOX <here>

SNOWPACK DISCUSSION:

Continental (Interior) Specific:  

Winds have just backed down after 2 days of strong NE flow. Many areas of soft snow has drifted and blown onto southerly aspects, forming fresh wind slab, sometimes resting on sun crust and triggering easily.

Dig and look for surface hoar, buried April 9, that was found all the way up to ridgeline. It was seen still standing under new snow near the summit of Girls Mountain and is likely existent in many areas…since it formed widespread prior. No reports yet of avalanches on this weak layer, so let us know if you see something.

It has been 5 days since some snow has fallen and over a week since the last significant snow storm. Quite the variable scenario exisits out there, from sun crust to firm wind board to nice pockets of preserved and faceting snow. Lower to mid elevations are going isothermal quickly with this warm weather. Timing is the name of the game this time of year, plan accordingly and monitor the evening freezing and afternoon warming closely.

Generally speaking the base of the snowpack in the interior region consists of sugar snow (basal facets). This is poor support for the rest of the snowpack and leads to the possibility of the entire season’s snowpack ripping out in a massive avalanche. These slides are most likely to be triggered in the afternoon sun.

Sharing your observations creates an informed community.

Recent Avalanche Activity

Continental (Interior) Specific: 

  • March 31: skier triggered size D2 avalanche at 3500′ North aspect. 40-60cm storm slab failed on buried near surface facets with a old windslab as the bed surface. A possible sympathetic released lower on the same slope, with a crown depth 60-100cm, harder slab.

Recent Weather

See Maritime Zone for updated weather.

Additional Info & Media

Weather Quicklinks:

SNOW CLIMATE ZONES:

  • coastal-zone-iconMaritime (Coastal) – from the Port of Valdez to Thompson Pass, all waters flowing into Valdez Arm and everything south of Marshall Pass.
  • intermountain-zone-iconInter-mountain (Transitional) – between Thompson Pass and Rendezvous Lodge.
  • interior-zone-iconContinental (Interior) – the dry north side of the Chugach (north of 46 Mile, including the Tonsina River).

Photo of Thompson Pass

thompson-pass-ski-runs

Interactive Map of Valdez Forecast Areas w/ Many Resource Layers (Trevor Grams)

climate-zones-topoclimate-zones-satellitegoogle-earth1

Run Map of Thompson Pass Area (Sean Wisner) (2MB download)
VAC Run Map Thompson Pass

NEWS: Our region is “one of the snowiest places on earth” – Serendipity / Rendezvous snowfall record set in 1963 <here>.

Free smart phone avalanche forecasts at: http://www.avalancheforecasts.com/

Posted in Continental Forecasts.

Forecaster: Kevin Salys