Valdez
Above 3,000ftModerate
1,500 to 3,000ftLow
Below 1,500ftLow
Degrees of Avalanche Danger
Avalanche Problems
Problem 1
Our forecast area has received a trace of new snow at valley locations with 1-2 inches expected up high. This is an insufficient amount of snow to affect the hazard. The main avalanche problem continues to revolve around old wind slabs created at the beginning of the month.
There have been several reports of natural and human triggered wind slab avalanches less than one foot in depth directly following the 4/1 wind event. The sensitivity of this layer has since decreased and the distribution of wind slabs that could be human triggered has moved from specific to isolated. Human triggered avalanches remain possible less than 1 foot in depth in very steep wind exposed terrain at upper elevations. Keep in mind that even small avalanches can have big consequences is steep and/or consequential terrain. Pay attention to the depth and sensitivity of wind slabs in the area you choose to travel.
Persistent weak layers exist below the very hard snow that is the 3/17 interface as well. These are unlikely to be affected by human triggers today. Recent mild weather and a lack of recent snowfall has allowed the snowpack to gain strength. These weak layers have the potential to reactivate later in the spring. This potential will be dictated by future weather.
Likelihood:
- Almost Certain
- Very Likely
- Likely
- Possible
- Unlikely
Size:
- Historic
- Very Large
- Large
- Small
Trend
- Increasing
- Steady
- Decreasing
Problem 2
Wet loose activity will be limited today due to clouds keeping the solar aspects cooler. Clouds during the first half of the day will limit the amount of time the suns energy can melt snow at the surface. If the sun comes out this afternoon, the possibility to see wet loose activity will be increasing. Todays activity is expected to be low volume and less widespread.
The size of the terrain being exposed will directly correlate to the size of natural activity that is possible. Small slopes will likely only produce roller balls and low volume wet loose activity. While large steep solar aspects have the potential of entraining significant amounts of snow and producing very dangerous, large wet loose avalanches. Steep areas near rocks will be the first to warm up during the day. Step downs to slab activity will become increasingly possible as the Spring moves on and the sun becomes more intense.
Assesment and avoidance of this avalanche problem is relatively easy. Pay attention to the amount of warmth that is being transferred into the snow surface (Is it becoming moist-wet?). Avoid traveling on or being exposed to steep solar aspects where the surface snow is becoming moist-wet during the heat of the day.
Likelihood:
- Almost Certain
- Very Likely
- Likely
- Possible
- Unlikely
Size:
- Historic
- Very Large
- Large
- Small
Trend
- Increasing
- Steady
- Decreasing
Problem 3
Weak snow exists at the base of our snowpack. This weak snow is currently unlikely to be affected due to the strength of old wind affected snow at the 3/17 new/old interface. Depth hoar may become a concern later in the season if our area returns to a period of major snowfall and the very strong wind damaged layer at the new/old interface starts to break down and lose strength within the snowpack. As very hard wind slabs break down within the snowpack a person or machines weight will have a more direct affect on weak layers at the bottom of the snowpack. In addition, the increasing intensity of the sun will be putting pressure on deep layers during the heat of the day.
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.
4/2- D1.5 skier triggered wind slab avalanche. NW aspect/~4000′.
4/1- Multiple skier triggered D1 avalanches were reported on a variety of aspects. These were wind slabs in the 4-8 inch range.
3/31- Skier triggered avalanche reported at high elevation of the Maritime climate zone. This failed on surface hoar that was buried on 3/30. No skier involvement. Crown depth was 4-8 inches.
3/24- Ski cuts were reported as being productive, with avalanches up to D2 at the 3/21 interface.
3/18-21- Several D1-D2 human triggered avalanches have been reported. For the most part these have been outside our forecast zone and appear to be more likely in areas with either a weaker underlying snowpack (continental zone) or where storm totals were higher (SE of Thompson Pass). Remote triggers have also been reported as the Hamilton storm slab has settled and gained cohesion.
3/17- Multiple D1-D2 natural storm slab avalanches were reported and observed along the road corridor. These all failed within the storm snow with the exception of one deep persistent avalanche reported on Billy Mitchell.
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, warnings and advisories
NONE
NWS Point forecast for Thompson Pass
Date Wednesday 04/05/23 Thursday 04/06/23 Time (LT) 04 10 16 22 04 10 16 22 04 Cloud Cover OV OV OV OV OV OV OV BK SC Cloud Cover (%) 100 95 95 90 90 90 90 60 45 Temperature 22 25 30 27 24 26 30 24 19 Max/Min Temp 31 24 30 18 Wind Dir NE NE NE NE NE E SW NW E Wind (mph) 3 5 4 4 3 3 4 2 3 Wind Gust (mph) Precip Prob (%) 50 50 40 60 60 60 60 40 30 Precip Type S S S S S S S S S 12 Hour QPF 0.08 0.08 0.17 0.12 12 Hour Snow 0.0 0.7 1.4 0.4 Snow Level (kft) 0.0 0.1 0.6 0.3 0.1 0.2 0.3 0.1 0.0
Click on link below for Thompson Pass weather history graph:
Date:
04/05 |
24 hr snow | HN24W* | High temp | Low temp | 72 hour SWE* | April snowfall | Seasonal snowfall | Snowpack Depth |
Valdez | Trace | 0 | 37 | 30 | 0 | 0 | 236 | 51 |
Thompson Pass | Trace | 0 | N/O | N/O | 0 | 0 | 428 | N/O |
46 mile | Trace | 0 | 37 | 24 | 0 | 0 | ~115** | 54 |
*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 above 3000 feet and low below. Wind slabs that formed on the 1st are gaining strength and new snow over the last 24 hours is insufficient to elevate the hazard. Shallow wind slabs may remain reactive in isolated locations above 3000 feet less than one foot in depth. The hazard at low elevation will move to moderate later in the day if skies clear, creating the potential for wet loose activity.
Posted by Gareth Brown 04/05 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.