Sunday-Wednesday 3/25-3/28

Issued: Sun, Mar 25, 2018 at 8AM

Expires: Wed, Mar 28, 2018

Bring your families and kids out to Beacons & Eggs. Saturday March 31 10am-noon. Salmon Berry Ski Hill at Mile 6. Learn and practice backcountry safety skills with some Easter fun.

Above 2,500ft Moderate

1,800 to 2,500ft Low

Below 1,800ft Low

Degrees of Avalanche Danger ?

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

Avalanche Danger Rose ?

Avalanche Problems ?

Problem Details

Sunday Monday Tuesday
& Wednesday
2-moderate 2-moderate 2-moderate

DANGER SCALE

 

 

WIND SLAB:
Elevation:   Above 1000′
Aspect:   Lee of ridges, gullies, ridgetops
Terrain:   All terrain exposed to northerly winds
Sensitivity:   Stubborn
Distribution:   Specific
Likelihood (Human Triggered):   Possible
Size:   Small – Large
Danger Trend:   Decreasing
Forecaster Confidence:    Good

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

LIST OF AVALANCHE PROBLEMS <here>

SNOWPACK DISCUSSION:

The March 19-22 northerly wind event has left the mountains raked over with much bare rock in between the hard, wind blasted slopes. Gullies got filled in with deep, smooth windslab. Alpine snow textures vary from undulating foot high sastrugi to tiny patches of less hard sand-dune like surfaces with many areas peeled back to old crusts.

What windslab was formed (a lot of snow sublimated into the atmosphere), is settling in and appears to be bonding to old snow. The last snow ended March 19.

In our recent test pits above 3000′ where wind slab is not formed, the top meter (3′) of snow is showing no signs of propagation.

Anticipating our next snow coming in Monday: if temperatures are cool, it may not bond with the current snow surfaces.

The warm daytime temperatures and longer solar radiation is causing southerly aspects to thaw, beware of the possibility of roller balls or small wet loose avalanches out of rocky steeps.

Check out our public observations <here>

Recent Avalanche Activity

March 22: A few pockets of windslab released on steep west facing gully walls and rollovers including a D2 wind slab on S facing slope at 3500′ near milepost 29.

March 21: Natural wind slabs to size D2, including onto the highway at Milepost 23.
March 19-20: Numerous natural wind slab releases to size D2 observed between Mileposts 22 and 29 across Thompson Pass with the initial onset of the present extreme northerly wind event, transporting available soft snow.

 

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F): 15 / 21
Ridgetop Wind Forecast (direction/mph): NE / 5-15
Snowfall (in):  0″
WIND & TEMPERATURE
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction  10 / NE   23 / NE
Max Wind Gust (mph) / Direction  12 / NE  32 / ENE
Temperature Min / Max (*F)  27 / 43  9 / 23

Weather Forecast:    Beautiful spring day. 20sF. Light to moderate north wind. Clear skies Sunday with cloud coming in Monday. A few flurries Monday night with a few inches snow accumulating through Tuesday.

Additional Info & Media

SNOW HISTORY: Valdez 3/25 AM Thompson Pass 3/25 AM
24 Hour Snow / Water Equiv. 0”/ 0.0″ 0″ / 0.0″
Storm Snow /Water Equiv. (3/15-19) 19” / 0.41″ 40″ / 1.5″
Current Snow Depth 32″ 84″
March Snow / Water Equiv. 20.5″ / 2.61″ 49″ / 3.6″
Total Winter Snowfall / Water Equiv. 132.59″ / 27.2” 372″ / 36.6″
Snowload in Valdez 55 lbs/sq. ft.

 

SNOW DEPTH & WATER SURVEY (3/4/2018) Depth Snow Water Equivalent
Milepost 2.5 Valdez  32.2″  9″
Milepost 18 42″ 11″
Milepost 29 Worthington Flats 62.4″ 21.2″
Milepost 37 Tsaina River bridge 58.4″ 14.2″
This survey is done the first week of each month.

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, Intermountain Forecasts, Maritime Forecasts.
Sarah Carter

Forecaster: Sarah Carter