Valdez

Forecast Expired - 01/20/2023

Above 4,000ftModerate

2,000 to 4,000ftModerate

Below 2,000ftLow

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Persistent Slab:

 Surface hoar was buried on 1/14, this has the potential to be a dangerous layer in the future, and has the ability to persist for long periods of time.  Currently, in most areas this layer is not buried deep enough to be a real concern.  

 

The potential to trigger avalanches exists in specific areas where the 1/14 BSH (buried surface hoar) is covered by wind slabs created on 1/17.  Winds could have created a slab that is stiff enough and deep enough to make this layer reactive to human triggers.  

 

The lee side of high elevation ridges and lee slopes in wind channeled terrain will be the areas where triggering a persistent slab avalanche about 1 foot in depth will be possible today.

 

In the next 48 hours the sensitivity for this problem should increase and the distribution will become more widespread.   Increasing temperatures and moderate to heavy snow will be building slabs atop weak snow that will be moving closer to the tipping point.  Snowfall is expected to be light today and will increase in the evening along with temperatures.

 

 

Surface Hoar from Girls Mountain at ~3000′ on 1/13 when it was still at the surface.

 

Likelihood:

  • Almost Certain
  • Very Likely
  • Likely
  • Possible
  • Unlikely

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Deep Slab:

Faceted snow at the base of our snowpack has not been reactive for 12 days, on 1/6 one outlier avalanche occurred at mid elevation near Thompson Pass (see avalanche activity section).  Prior to this, avalanches haven’t occurred since 12/16 at these deep layers.

 

A slowly building snowpack and recent benign weather have allowed our snowpack to slowly gain strength.  Rounding (strengthening) has been observed at these facets in all three forecast zones, but this process takes a lot of time.  At this point triggering an avalanche at this layer is very unlikely.  Once significant snowfall returns to our area, expect for the potential to affect these deep layers to increase.

 

Unlikely does not mean impossible, and triggering an avalanche deep in the snowpack would carry significant consequences.  The most likely place to affect these layers would be in thin, rocky areas in the Continental zone.  

 

 

Rounding facets near the base of our snowpack from Cracked Ice at 4000′ on 1/11.

Likelihood:

  • Almost Certain
  • Very Likely
  • Likely
  • Possible
  • Unlikely

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

Below is a summary of observed Avalanche activity from the last 7 days.  Avalanches that were noted earlier in the season can be viewed by clicking the link below.

If you trigger or observe a natural avalanche consider leaving a  public observation.

Valdez Avalanche Activity

1/17- Numerous wet loose point release were observed on solar aspects in the Port of Valdez.  Most of these originated from rocks were the suns energy permeated into dry snow and caused surface snow to become upside down.  No step down slab avalanches were observed.

 

-Small (D1) spin drift avalanches on the lee side of Tones Temple ridge triggered a small slab at the 1/14 BSH layer.

 

Weather

Check out our updated weather tab!  A collection of local weather stations are available for viewing with graphs and tabular data included.

NWS Watches and warnings

NONE
NWS Point forecast for Thompson Pass
Today
Snow. High near 21. Northeast wind around 15 mph, with gusts as high as 20 mph. Chance of precipitation is 80%. Total daytime snow accumulation of 1 to 2 inches possible.
Tonight
Snow. Low around 17. Southeast wind around 10 mph. Chance of precipitation is 90%. New snow accumulation of 3 to 5 inches possible.
Friday
Snow likely. Cloudy, with a high near 29. East wind 5 to 10 mph becoming light. Chance of precipitation is 70%. New snow accumulation of around an inch possible.
Friday Night
Snow likely, mainly before midnight. Cloudy, with a low around 13. Northeast wind 10 to 15 mph. Chance of precipitation is 70%.
Saturday
A 30 percent chance of snow before 9am. Cloudy, with a high near 27. East wind around 5 mph.
Saturday Night
Snow likely, mainly after 3am. Mostly cloudy, with a low around 12. Northeast wind around 5 mph becoming calm after midnight. Chance of precipitation is 60%.
Detailed forecast for Thompson Pass Mid elevation (2000-4000 Feet)
Date               Thursday 01/19/23       Friday 01/20/23         
Time (LT)          06    12    18    00    06    12    18    00    06
Cloud Cover        OV    OV    OV    OV    OV    OV    OV    OV    OV
Cloud Cover (%)    90    90   100   100    90    90    90    90    90
Temperature        15    18    21    21    24    25    25    19    22
Max/Min Temp                   22          19          29          14
Wind Dir            E    NE     E    SE    SE     E    NE     N     N
Wind (mph)         14    12    13    10     8     4    10     9    10
Wind Gust (mph)    26                                                
Precip Prob (%)    60    70    80    90    70    70    70    50    20
Precip Type         S     S     S     S     S     S     S     S     S
12 Hour QPF                  0.19        0.42        0.12        0.12
12 Hour Snow                  2.9         5.7         1.5         1.3
Snow Level (kft)  0.0   0.3   1.0   1.6   1.4   1.3   0.7   0.5   0.3
Click on link below for Thompson Pass weather history graph:

https://docs.google.com/spreadsheets/d/e/2PACX-1vR_Fl5087NrNCo2BtsSaum-gxrx1QioHSO4YqEmjW76LhuDu9ZsSxbBCTl6zkYIFarys-5eM_7P5GpV/pubhtml

 

 

 

Date:

01/19

24 hr snow HN24W* High temp Low temp 72 hour SWE* January snowfall Seasonal snowfall Snowpack Depth
Valdez 2 .2 34 21 .26 28 125 47
Thompson pass  2 N/O N/O N/O N/O 56 250 38
46 mile N/O N/O 6 -6 N/O 24 ~60** 36

 

 

*HN24W- 24 hour Snow water equivalent in inches

*SWESnow water equivalent

**46 mile seasonal snowfall total begins December 1st.

Additional Information

 

Click on the link below for a running summary of the seasons weather history.

Valdez Weather History

Announcements

The avalanche hazard is moderate above 2000′.  Human triggered avalanches are possible up to 1 foot in depth, in previously wind loaded terrain.  Fresh wind slabs formed Tuesday sit on weak snow that is expected to remain sensitive longer than what is typical.  Watch for signs of instability such as shooting cracks and use small test slopes to check the sensitivity of previously wind loaded terrain.  

Posted by Gareth Brown 01/19  8:00 am.

 

For a description of current avalanche problems, weather information, season history and more click the (+ full forecast) button.  Avalanche forecasts will be issued Wednesday-Sunday.

If you have pictures of recent natural or human triggered avalanches or notice signs of instability such as shooting cracks or collapsing, leave an observation to help improve forecast accuracy.