Wednesday – Saturday 3/29-4/1

Issued: Wed, Mar 29, 2017 at 8AM

Expires: Sat, Apr 01, 2017

18” of new snow over the last 72 hours. Be aware of what is above and around you as natural avalanches large enough to bury and kill a person are possible.

Avalanche Center Tsaina Lodge Spring Full Moon Bon Fire FUNraiser

Friday April 14 presenting Acoustic Avalanche

Above 2,500ft Considerable

1,800 to 2,500ft Considerable

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

WEDNESDAY THURSDAY FRIDAY & SATURDAY

DANGER SCALE

 

STORM SLAB

Elevation: All
Aspect: All
Terrain: All
Sensitivity: Responsive
Distribution: Widespread
Likelihood (Human Triggered): Possible
Size: Small – Large
Danger Trend: Increasing
Forecaster Confidence: Good

WIND SLAB:

Elevation:   Above 2000′
Aspect:  Lee to northerly and easterly winds
Terrain:   Near ridges, gullies, rollovers
Sensitivity:   Responsive
Distribution:   Specific
Likelihood (Human Triggered):   Possible
Size:   Small – Large
Danger Trend:   Increasing
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:

Maritime (Coastal) Specific: 

The storm is warming up with temperatures reaching above freezing yesterday in town. Significant precipitation has fallen over the last 72 hours in the maritime regions with close to 2 feet above 500′ on Sugarloaf Mountain. You are most likely to trigger a storm slab avalanche today, with wind in the mix this slab could be over 3 feet thick. Human triggered avalanches were reported on the road run yesterday. Be aware of what is above you, as heavy storms like this commonly produce larger natural avalanches that could bury and kill a human.

Find more photos and observations at the bottom of the page. Sharing your observations creates an informed community that everyone benefits from at some point.

Recent Avalanche Activity

Maritime (Coastal) Specific: 

  • March 28 human triggered avalanches on the road run
  • Expect fresh windslab/stormslab to be sensitive, especially where it is building on old hard surfaces
  • March 25 reports of upper elevation (>4500′ elevation) human triggered windslabs to a foot thick releasing off steep slopes.

Recent Weather

WEATHER FORECAST for NEXT 24 HRS at 3,000 ft:
Temperature Forecast (Min/Max *F):  23 / 29
Ridgetop Wind Forecast (direction/mph):  SE / 14-25
Snowfall (in/water equivalent):  3-11″ / 0.88″
WIND & TEMPERATURE
PAST 24 hours
Ferry Terminal Thompson Pass
Average Wind Speed (mph) / Direction  3 / NE  18 / SE
Max Wind Gust (mph) / Direction  5 / NE  28 / SE
Temperature Min / Max (*F)  29 / 34  22 / 28

Weather Forecast:  Warmer temperatures today with the potential of rain in town. It seems that later this week temperatures have the potential to rise into the 40s. Winds are continuing to blow from the southeast, enough for moderate snow transport. The first bit of sun coming out will be early next week, if at all.

Additional Info & Media

SNOW HISTORY: Valdez 3/28 AM Thompson Pass 3/29 AM
24 Hour Snow / Water Equiv.  3.12”/.55″ 8″ /0.8″
Storm Snow /Water Equiv. (3/27)  10.53″ /.00″ 18″ /1.8″
Current Snow Depth 45.63″ 42″
March Snow / Water Equiv. 14.04″ /1.17″ 29″ / 2.2″
Total Winter Snowfall / Water Equiv. 236.93″ /22.09” 312″ / 29.9″
Snowload in Valdez 52.0 lbs/sq. ft.

 

SNOWFALL at OTHER STATIONS:
LAST 24 HRS (3/29 AM)/STORM TOTAL (3/27)/STORM WATER EQUIV.:
Nicks Valley at 4200 ft (in): 4″ / 7″ / 0.7″
Upper Tsaina at 1750 ft (in): 3″ / 5″ / 0.6″
Sugarloaf at 550 ft (in): 5″/ 15″ / 1.6″
SNOW DEPTH & WATER SURVEY (2/28/2017) Depth Snow Water Equivalent
Milepost 2.5 Valdez  41.8″  12″
Milepost 18 42.7″ 11.5″
Milepost 29 Worthington Flats 63.6″ 18.6″
Milepost 37 Tsaina River bridge 49.3″ 12.5″
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 Maritime Forecasts.
Kyle Sobek

Forecaster: Kyle Sobek