Valdez

Forecast Expired - 12/30/2022

Above 4,000ftModerate

2,000 to 4,000ftModerate

Below 2,000ftModerate

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Wind Slab:

Currently, in many areas 6-12 inches of uncohesive (no slab)  snow sits atop a layer of unreactive wind damaged snow.  Human triggered avalanches up to 1 foot+ deep will be possible on lee aspects that have been loaded with this new snow by recent winds, creating cohesive snow (slab).  Wind slabs could exist on a variety of aspects due to changing wind directions.  Although, will be more sensitive on slopes loaded by E-SE winds, as this has been the most current direction of winds.  

 

Stability assessment should be fairly straightforward today.  Watch for where and if recent wind has redistributed new snow.  Hard snow over soft at the surface, shooting cracks, and collapsing are all indicators of a wind loaded slope with the potential to produce an avalanche. Terrain to be cautious of includes: lee side of high elevation ridge lines, cross loaded gullies and steep convex terrain. 

 

The hazard will be lower in areas where surface snow is unaffected by wind.

 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Persistent Slab:

Faceted snow near the base of the snowpack has been identified in all three forecast zones. In most locations above brush line, faceted snow is capped by pencil-knife hard wind affected snow.  This has created a strong bridging affect above 3000′,  making a person or machines weight unlikely to directly affect these layers. 

It has been 12 days since the last significant snowfall event, and stability tests that directly target these layers have not been producing significant results lately.

Persistent weak layers are tricky to assess and are notorious for surprising people.  As long as temperatures remain cold and our snowpack is thin, these weak layers will continue to lose strength.  It is likely that facets will reactivate in the future when stress is being applied through dramatic changes in weather such as: significant snow accumulation or rapid warming.  Maintaining safe travel protocols such as skiing one at a time and avoiding traveling in or above terrain traps will increase your safety margin.  

 The most likely areas to trigger a persistent slab avalanche would be in steep terrain that was protected from previous strong winds that have occurred this season. This could be below brushline in steep open places, or in areas of terrain that are typically spared from outflows.  The Continental zone remains suspect as this area has a weaker snowpack and generally receives less wind, which would decrease the bridging affect mentioned above.

 

 

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

No recent avalanche activity has been recorded in the last 7 days.  

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

...POTENTIAL FOR STRONG LOW TO BRING WINDS AND WINTRY MIX TO
SOUTHCENTRAL THIS WEEKEND...

We are monitoring the potential for an impactful weather event to
occur across Southcentral this weekend.

Weather models have not been consistent over the last 48 hours,
which has resulted in lower forecast confidence, however, all
models are keying in on a strengthening area of low pressure that
will move from the north Pacific into the western Gulf sometime late
Saturday night into early Sunday.

This low has the potential to bring strong, gusty easterly winds
to much of the northern Gulf, including Kodiak Island.
Accompanying this area of low pressure is a deep fetch of moisture
which will introduce warmer temperatures. This may result in a
wintry mix of precipitation including rain, snow, freezing rain,
sleet, or a combination of all throughout the event.

At this time, we are not certain about the exact timing, amount
of precipitation, or which locations will see which types of
precipitation. All of this depends on the track the area of low
pressure will take, and we are continuing to analyze that
information.

Please monitor the forecast in the coming days. We will be making
frequent updates as we work to refine these details.
NWS Point forecast for Thompson Pass
Today
Partly sunny, with a temperature falling to around 8 by 11am. Northeast wind 10 to 15 mph, with gusts as high as 25 mph.
Tonight
Mostly cloudy, with a low around 3. Northeast wind around 15 mph, with gusts as high as 30 mph.
Friday
Mostly cloudy, with a high near 17. Northeast wind around 15 mph, with gusts as high as 30 mph.
Friday Night
Snow likely, mainly after 9pm. Cloudy, with a low around 16. East wind 10 to 15 mph becoming south after midnight. Winds could gust as high as 20 mph. Chance of precipitation is 60%.
Saturday
A 40 percent chance of snow. Mostly cloudy, with a high near 24. South wind around 10 mph becoming east in the afternoon.
Saturday Night
Snow, mainly after 3am. Low around 17. East wind 5 to 10 mph becoming light and variable after midnight. Chance of precipitation is 90%.
Detailed forecast for Thompson Pass Mid elevation (2000-4000 Feet)
Date               Thursday 12/29/22       Friday 12/30/22         
Time (LT)          06    12    18    00    06    12    18    00    06
Cloud Cover        BK    BK    BK    OV    OV    OV    OV    OV    OV
Cloud Cover (%)    65    55    70    80    80    80    85    90    85
Temperature        15    10     9     5     9    14    17    19    19
Max/Min Temp                   16           5          17          16
Wind Dir            E    NE    NE    NE    NE     E     E    SE    SE
Wind (mph)          6     8     9     9     9     3     3     4     3
Wind Gust (mph)          20    25    26    27    24    20            
Precip Prob (%)     5    10     5     0     5    10    30    60    40
Precip Type                                             S     S     S
12 Hour QPF                  0.00        0.00        0.00        0.08
12 Hour Snow                  0.0         0.0         0.0         1.0
Snow Level (kft)  0.0   0.0   0.0   0.1   0.2   0.0   0.2   0.1   0.2
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:

12/29

24 hr snow HN24W* High temp Low temp 72 hour SWE* December snowfall Seasonal snowfall Snowpack Depth
Valdez ~3 N/O 32 26 ~.3 59 94 39
Thompson pass  1 .05 27 23 ~.55 89 190 24
46 mile N/O N/O 11 5 N/O ~25 ~34** 29

 

 

*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.  Once again, the hazard today  primarily involves windslabs.  Avalanche hazard will be concentrated to areas where the new 6-12 inches of low density new snow has been loaded by recent winds.  Human triggered avalanches up to 1 foot in depth are possible in specific terrain, natural avalanches are unlikely.

Posted by Gareth Brown 12/29  7:30 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.