Buried surface hoar is expected to be widespread in the Thompson Pass region. Buried surface hoar is a notoriously weak snow grain that is historically responsible for many accidents with instability potentially lingering for long amounts of time.
This layer has been identified on all aspects and elevations. In most locations this weak layer is buried by about 1 foot of uncohesive (no slab) snow. In these locations this weak snow is stubborn to unreactive so far. In specific locations where northeast winds have loaded slopes deeper, this layer is under more stress and human triggered avalanches are possible 1-2 feet in depth. Several natural avalanches were observed on wind loaded slopes that failed at this layer on 1/19. Propagation in stability tests was observed on 1/21 at 5200′ on Cracked Ice where storm snow was deeper and slightly wind pressed at the surface.
Today areas of concern will be the lee side of high elevation ridge lines, any wind loaded slopes and areas where more than a foot of snow exists above this weak layer. It is unclear at this point if this weak snow remains preserved in the Maritime climate zone where a significant warm up has occurred.
There will not be a forecast posted on Monday or Tuesday. Expect for the hazard of this avalanche problem to increase as our area receives more precipitation and rising temperatures.
Weak snow exists near the base of our snowpack in all three climate zones. These weak layers have not been thoroughly tested by significant snowfall since the New Years storm. Benign weather the last few weeks has allowed this weak snow to become dormant with no major natural activity since 12/16.
Conditions may change this week as our area is expecting fairly consistent precipitation will rising temperatures that may bring rain up to 2500′ by Wednesday. Deep slab avalanches will become more likely as this change in weather occurs. Deep instabilities are difficult to assess. As snow levels rise and precipitation potentially becomes heavy later this week, avoidance of avalanche terrain is often the most reasonable mitigation practice for this problem.
Rounding facets near the base of our snowpack from Cracked Ice at 4000′ on 1/11.
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
1/21- Several D2 natural avalanches were observed on wind loaded slopes that failed at the 1/14 BSH interface. These probably occurred on 1/19. Avalanches were observed on Hippie Ridge South aspect, RFS Northwest aspect, Cracked Ice Northwest aspect and Python (Cherry couloir) East aspect. These all appeared to be 1-2 feet deep.
1/20- Numerous large (D2) wet loose avalanches released from steep planar slopes in the Port of Valdez. These were caused by a foot or more of snow falling with temperatures rising to 40° F at sea level directly following. No step downs noted.
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.
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
NWS Point forecast for Thompson Pass
Date Sunday 01/22/23 Monday 01/23/23
Time (LT) 06 12 18 00 06 12 18 00 06
Cloud Cover OV OV OV OV OV OV OV OV OV
Cloud Cover (%) 90 100 100 95 100 90 95 95 100
Temperature 21 24 24 20 24 27 29 28 28
Max/Min Temp 26 20 30 27
Wind Dir E E NE E SE S S S S
Wind (mph) 8 10 10 9 10 16 20 20 13
Wind Gust (mph) 32
Precip Prob (%) 70 80 80 70 90 90 90 100 90
Precip Type S S S S S S S S S
12 Hour QPF 0.14 0.19 0.30 0.37
12 Hour Snow 1.8 3.4 3.7 4.1
Snow Level (kft) 0.6 0.4 0.5 1.0 1.5 1.5 1.6 1.5 1.3
Click on link below for Thompson Pass weather history graph:
*HN24W- 24 hour Snow water equivalent in inches
*SWE– Snow water equivalent
**46 mile seasonal snowfall total begins December 1st.
Click on the link below for a running summary of the seasons weather history.
Valdez Weather History
The avalanche hazard is moderate at all elevations. Human triggered avalanches 1-2 feet deep are possible in areas previously loaded by northeast wind. Old wind slabs are sitting on weak snow that will cause instability to last longer than what is typical. No forecast will be posted on Monday-Tuesday. Expect for the avalanche hazard to increase as more stress is applied to weak snow near the surface through precipitation and rising temperatures.
Posted by Gareth Brown 01/22 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.
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