Valdez
Above 3,000ftModerate
1,500 to 3,000ftModerate
Below 1,500ftModerate
Degrees of Avalanche Danger
Avalanche Problems
Problem 1
North winds ramped up on 2/20 with gusts to 50 mph along ridge tops. Wind slabs were found to be initially sensitive up to 1 foot in depth on SE-NW aspects. On 2/21 slabs were found to be gaining strength and stubborn to triggers.
In many places these slabs were deposited on very low density snow, making slabs quite sensitive initially. This interface has been compressed since and sensitivity has decreased, although this problem may remain reactive in specific locations today up to 1 foot in depth. As slabs settle and gain strength the likelihood of triggering one of these decreases, but propagations could be wider due to the stiffness of the slab. Failure could occur once a person or machine is already on slope and initiate behind you. This problem will currently have a hollow drum like feel, shooting cracks will be a sign that avalanches remain possible.
Areas where the surface is unaffected by wind will provide better riding conditions and good stability.
Likelihood:
- Almost Certain
- Very Likely
- Likely
- Possible
- Unlikely
Size:
- Historic
- Very Large
- Large
- Small
Trend
- Increasing
- Steady
- Decreasing
Problem 2
Rain crusts that formed in late January have promoted faceting in the mid snowpack at low elevations (below 2500′). No natural or human triggered avalanches have been reported or observed that failed at this layer, although poor structure exists and stability tests have produced propagation at this interface.
As time goes on and this layer becomes deeper in the snowpack with additional snowfall, the likelihood of human triggers will be decreasing. It is still worth investigating this layer if traveling in steep/ consequential terrain at low elevations. Areas where the snowpack is thin will be the most susceptible to failures at this plane.
Likelihood:
- Almost Certain
- Very Likely
- Likely
- Possible
- Unlikely
Size:
- Historic
- Very Large
- Large
- Small
Trend
- Increasing
- Steady
- Decreasing
Problem 3
Weak snow continues to exist near the base of our snowpack in all three climate zones. 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). This layer is believed to be dormant as there has not been deep avalanche activity for 3 weeks, and only 2 observed in 2 months. 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. Unlikely does not mean impossible, if a person were to affect weak snow near the ground it would 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. An example of the difference in faceted snow that has been recently found can be seen below.
Depth hoar from Nicks Buttress ~4000′ North aspect 1/31. This was from an area where the snowpack 3 feet deep.
Rounding depth hoar on Cracked Ice / north aspect/ 3000′ on 2/11. This was from an area where the snowpack was 7 feet deep
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.
2/20- Numerous D1-D2 natural and human triggered avalanches were observed and reported up to 1 foot in depth on a variety of aspects. These occurred in areas where fresh wind slabs were present.
– D3 natural avalanche observed on Snoopys (Port of Valdez). NW aspect/ ~5000’/ ran ~3500 vertical feet with a track length of approximately 1 mile mapped on Google Earth. This was a hard slab avalanche the failed at weak layer in the mid snowpack. HS-N-R4 D3. No other avalanches of this size have been observed or reported in our forecast area.
2/15- The sun came out in full force after 6 inches of new snow and produced a significant amount of point release wet/loose activity near the coast on solar aspects. 2- D2’s were also noted in the mid and high elevation band of town mountain and Mile high.
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
Date Wednesday 02/22/23 Thursday 02/23/23 Time (LT) 06 12 18 00 06 12 18 00 06 Cloud Cover BK BK OV OV OV OV OV OV OV Cloud Cover (%) 50 55 85 95 100 100 100 95 100 Temperature 9 18 17 13 15 22 25 22 20 Max/Min Temp 23 13 26 19 Wind Dir NE NE NE SW S S S SE W Wind (mph) 4 6 2 4 8 10 6 3 4 Wind Gust (mph) 21 23 Precip Prob (%) 5 0 20 60 70 80 80 70 80 Precip Type S S S S S S S 12 Hour QPF 0.00 0.05 0.14 0.12 12 Hour Snow 0.0 0.5 2.0 1.5 Snow Level (kft) 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.1 0.1
Click on link below for Thompson Pass weather history graph:
| Date:
02/22 |
24 hr snow | HN24W* | High temp | Low temp | 72 hour SWE* | February snowfall | Seasonal snowfall | Snowpack Depth |
| Valdez | 0 | 0 | 36 | 13 | 0 | 69 | 214 | 63 |
| Thompson pass | 0 | 0 | 17 | 8 | 0 | 69 | 356 | 67 |
| 46 mile | 0 | 0 | 22 | -5 | 0 | ~16 | ~85** | 42 |
*HN24W- 24 hour Snow water equivalent in inches
*SWE– Snow 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.
Announcements
The avalanche hazard is moderate at all elevations. It remains possible to trigger wind slabs up to 1 foot in depth created by strong north winds 2/20. The sensitivity of wind slabs is decreasing, but remains a concern. The most likely places to encounter unstable snow will be on the lee side of ridge lines and cross loaded gullies. Wind slabs will likely have a hollow drum. Watch for signs of instability such as shooting cracks and/or recent avalanche activity.
Posted by Gareth Brown 02/22 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.