Valdez

Forecast Expired - 02/11/2023

Above 4,000ftModerate

2,000 to 4,000ftModerate

Below 2,000ftModerate

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Wind Slab:

Northeast wind ramped up to moderate-strong in our forecast area 2/9.  sensitive wind slabs were observed on Thursday at upper elevations in wind channeled terrain and on the lee side of ridges.  Stable conditions were observed in areas unaffected by wind.  

 

It will be possible to trigger a wind slab avalanche 1-3 feet in depth in specific areas.  Indicators of wind slab include, hard snow over soft and pillowed snow surfaces.  Shooting cracks, collapsing or recent avalanche activity are all signs that unstable snow exists that is capable of producing avalanches.

 

Winds are forecasted to switch to southeast by the afternoon and become strong by later tonight as another storm approaches our area.  This change in wind direction will be loading different aspects.

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Persistent Slab:

Below 2500′ 18-36″ of settled storm snow is sitting on the 1/25 rain crust.  This rain crust has lost strength since it has formed and has created a weak layer.  It will be possible for the 1/25 rain crust to act as a failure plane in steep terrain at low elevations.  

 

Watching for signs of instability such as shooting cracks and digging snowpits are a good idea if choosing to travel in steep terrain at low elevations.

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 3

Deep Slab:

Weak snow continues to exist near the base of our snowpack in all three climate zones.  This weak snow has recently been under increasing pressure as heavy snowfall and strong winds occurred 2/5-7.  The last recorded avalanche activity at this layer occurred during the 1/23-25 storm on Nicks Buttress / ~3500’/ north aspect (see avalanche activity section).  The amount of snow and wind our area just received was significant, and was a great strength test of weak snow near the base of our snowpack.  No avalanches have been observed that failed or stepped down to this layer during the latest storm.  Human triggered avalanches are currently unlikely to occur that fail on weak snow near the base of our snowpack.

 

Faceted snow near the ground has been found to vary significantly from place to place.  In most locations this snow has been found to be rounding (gaining strength) and unreactive in stability tests.  In thin areas of the snowpack these facets are significantly more developed.  The most likely places to affect weak snow near the ground will be in areas where the snowpack is thin.

 

If you find it is possible to push a ski pole to the ground in areas you travel.  Assume that a weak faceted snowpack exists in that location, that could act as a trigger point.

 

Depth hoar from Nicks Buttress ~4000′ North aspect 1/31.

 

 

 

 

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 an avalanche consider leaving a  public observation.

Valdez Avalanche Activity

 

2/7- DOT avalanche control work on 2/7 produced several D2-2.5 avalanches. All of these appear to have failed at the new snow/old interface without any step downs observed.  Avalanche activity mostly occurred in the mid elevation band 3500′-4000′ on the Buttresses of RFS, Cracked Ice, and Python.  The most significant results occurred on Berlin Wall at ~5000′ with a crown that looks to exceed 2 meters.  This was likely due to significant wind loading during the storm.

Very little natural avalanche activity was observed.

 

2/9- Several small (D1) natural avalanches were observed that failed on steep wind loaded terrain.

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, mainly after 3pm. Areas of blowing snow after noon. High near 16. Northeast wind 15 to 20 mph increasing to 25 to 30 mph in the afternoon. Chance of precipitation is 80%. Total daytime snow accumulation of around an inch possible.
Tonight
Snow. Areas of blowing snow before 3am. Low around 16. East wind 25 to 30 mph decreasing to 15 to 20 mph after midnight. Chance of precipitation is 100%. New snow accumulation of 3 to 5 inches possible.
Saturday
Snow. Areas of blowing snow between 9am and 3pm. High near 27. Southeast wind around 15 mph, with gusts as high as 35 mph. Chance of precipitation is 100%. New snow accumulation of 3 to 5 inches possible.
Saturday Night
Snow. Low around 15. Southeast wind 5 to 15 mph becoming northeast after midnight. Winds could gust as high as 30 mph. Chance of precipitation is 100%.
Sunday
Snow likely. Cloudy, with a high near 22. Northeast wind 5 to 10 mph becoming light and variable in the afternoon. Chance of precipitation is 70%.
Sunday Night
Snow likely, mainly before midnight. Mostly cloudy, with a low around 10. Light and variable wind becoming northeast 25 to 30 mph in the evening. Winds could gust as high as 35 mph. Chance of precipitation is 60%.
Detailed forecast for Thompson Pass Mid elevation (2000-4000 Feet)
Date               Friday 02/10/23         Saturday 02/11/23       
Time (LT)          06    12    18    00    06    12    18    00    06
Cloud Cover        SC    OV    OV    OV    OV    OV    OV    OV    OV
Cloud Cover (%)    40    95    95   100   100   100   100    85   100
Temperature         3    10    16    18    21    25    25    21    17
Max/Min Temp                   17          16          27          16
Wind Dir           SE    SE     E    SE    SE    SE    SE    SE    NE
Wind (mph)          6    13    24    16    13    14    13     6     5
Wind Gust (mph)    20    28    39    28          28    33            
Precip Prob (%)     0    40    80   100   100   100   100    90    60
Precip Type               S     S     S     S     S     S     S     S
12 Hour QPF                  0.09        0.30        0.35        0.13
12 Hour Snow                  1.0         4.7         4.7         1.8
Snow Level (kft)  0.0   0.0   0.0   0.2   0.5   0.7   0.6   0.4   0.1
 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:

02/11

24 hr snow HN24W* High temp Low temp 72 hour SWE* February snowfall Seasonal snowfall Snowpack Depth
Valdez 0 0 32 17 .45 37 182 64
Thompson pass  0 0 N/O N/O N/O 52 341 62
46 mile 0 0 20 -12 N/O 13 ~80** 48

 

 

*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 at all elevations.  Human triggered avalanches are possible in recently wind loaded terrain 1-3 feet in depth.  Hard snow over soft is an indication of wind loaded snow and shooting cracks are a bullseye sign that unstable snow exists.

Posted by Gareth Brown 02/10  6:30 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.