Valdez

Forecast Expired - 01/27/2022

Above 4,000ftConsiderable

2,000 to 4,000ftConsiderable

Below 2,000ftModerate

Degrees of Avalanche Danger

Avalanche Problems

Problem 1

Wind Slab:

Our main concern today will be areas where the most recent storm snow has been redistributed by southeast wind onto lee aspects.  Instabilities will exist in specific locations including cross loaded gullies and the lee side of ridge lines.  Watch for signs of wind loaded slopes like fresh wind lips/cornices, pillowed snow surfaces and shooting cracks.

 

Another round of snow will begin to move in today.  Only light snowfall is expected today before increasing in intensity overnight.  New snow and wind will be adding weight to already sensitive wind slabs.

On 1/25 storm slabs were found to be right side up with signs of instability existing in areas where southeast winds had formed slabs 1-2 feet in depth on the lee side of terrain features.  Fresh wind lips and the lee side of test slopes were reactive on 1/25 up 2 feet deep.  Dangerous conditions likely exist in high elevation start zones on the lee side of ridge lines.  Pay attention to how the surface snow has been redistributed by wind in the area you are traveling.  Areas where surface snow is stacked up into deeper and more dense pockets will have a higher likelihood of producing an avalanche.  There is a chance that smaller avalanches could step down to weak/faceted snow deeper in our snowpack (see problem 2)

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Problem 2

Deep Slab:

In many locations developed facets exist in our mid to lower snowpack.  These facets have been stressed by warm temperatures and heavy precipitation.  These weak layers will need time to adjust to the added weight that the recent storm delivered.  In many areas above 3000′ these facets have been capped by knife hard wind slabs making them more difficult to affect.  Pole probing often along your route is a good way you can determine what’s overlying faceted snow in our lower snowpack.  

 

Storm slabs may be able to step down to these weak layers creating very large destructive avalanches.  The most likely place to encounter this avalanche problem is in the Continental zone in thin rocky areas where weak faceted layers are more easily affected.  

 

 

(2mm grid) Photo of chained facets found in the low elevation area of Girls Mountain 1/13.  In many areas these facets are capped by knife hard wind slabs making them difficult to affect and detect.

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

In many locations developed facets exist in our mid to lower snowpack.  These facets have been stressed by warm temperatures and heavy precipitation.  These weak layers will need time to adjust to the added weight that the recent storm delivered.  Smaller avalanches may be able to step down to these weak layers creating very large destructive avalanches.  The most likely place to encounter this avalanche problem is in the Continental zone in thin rocky areas where weak faceted layers are closer to the surface, making them easier to affect.  

 

 

(2mm grid) Photo of chained facets found in the low elevation area of Girls Mountain 1/13.  In many areas these facets are capped by knife hard wind slabs making them difficult to affect and detect.

 

 

 

 

 

 

Likelihood:

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

Size:

  • Historic
  • Very Large
  • Large
  • Small

Trend

  • Increasing
  • Steady
  • Decreasing

Avalanche Activity

1/22-  Clouds made observing avalanche activity difficult, although numerous large wet loose slides were observed on south aspects of Town Mountain in the Port of Valdez.

1/13- Multiple large natural avalanches were noted following the snowfall on 1/13.  Most were near high elevation ridge lines, although mid elevation storm slabs were noted on north aspect of Catchers Mitt and south aspect of Mile high.  Other avalanche not shown in photos include Goodwills north aspect and Oddeyssey north aspect.

 

1/1-1/4-  The new years day wind event created an avalanche cycle that was difficult to document due to crowns being rapidly reloaded by 80 mph winds.  Below are photos of a couple very large slides that were still visible in the Hippie ridge area.  Naturals were also noted on Three Pigs, 40.5 Mile, Crudbusters, Python Buttress.

 

12/29-  Multiple natural wet loose D1-D2’s were observed in the Port of Valdez with no step downs noted.

12/23- Berlin Wall north face ~5000′ HS-N-R3-D2-O.  It is possible this occurred on 12/21, although it was not observed until 12/24.

12/21- Numerous natural avalanches observed all along the north side of Thompson Pass, as a result of strong NE wind event along with a couple inches of new snow and rising temperatures.  Observed naturals on all aspects except windward slopes with crowns originating from 1000 feet to 5500 feet in elevation.  Most of these were hard slab avalanches.  Crown depths were difficult to discern due to reloading, although some crowns looked to be up to 2 meters in depth.

12/19- D 2.5 natural avalanches were observed on the north facing buttress west of Gully 1 and Schoolbus.  

12/14-  Several natural avalanches were observed although poor visibility prevented a full view of the action.  The most notable natural was observed in Nicks Happy Valley on a NW aspect ~4000′.  Crown depth was not visible.  Debris ran down the valley and piled up at the typical snowmachine pickup.

12/8- Large remote trigger/ sympathetic avalanche event occurred 12/8 with avalanches extending from Gully 1 to Nicks.  Avalanches were soft slabs that ranged in size from D1-D3.  Over 10 separate avalanches were counted with crown depths averaging 2-3′.  One avalanche had a crown length of half a mile while another was triggered over a mile away from the point of collapse.  See observation section for full report and more photos.

12/7- Only a few natural avalanches were noted during the last storm.  It is likely there were more during the storm, but crowns may have been filled in by subsequent wind and snow.

D2’s on Town mountain was observed ~3000′

A couple of D2’s were noted in N. Oddessey gully and Big Oddessey.

D2 on 40.5 mile peak ~5500′.

12/2-12/3- Several natural D2 avalanches were noted on south aspects of Three pigs, Hippie Ridge and Averys.  These windslab avalanches originated between 4000-5500 feet elevation.

Weather

NWS Watches and Warnings


None


 


Point forecast for Thompson Pass

Today
Snow likely, mainly after noon. Cloudy, with a high near 25. Light and variable wind becoming northeast 5 to 10 mph in the afternoon. Chance of precipitation is 60%. Total daytime snow accumulation of less than one inch possible.
Tonight
Snow. Areas of blowing snow after 9pm. Low around 19. Northeast wind 15 to 25 mph. Chance of precipitation is 80%. New snow accumulation of 1 to 3 inches possible.
Thursday
Snow. Areas of blowing snow. High near 22. Northeast wind around 30 mph. Chance of precipitation is 90%. New snow accumulation of 4 to 7 inches possible.
Thursday Night
Snow. Areas of blowing snow. Low around 12. Northeast wind around 30 mph. Chance of precipitation is 80%.
Friday
Snow likely. Areas of blowing snow. Cloudy, with a high near 19. Northeast wind around 30 mph. Chance of precipitation is 70%.
Friday Night
Snow likely, mainly before 9pm. Areas of blowing snow before 9pm. Cloudy, with a low around 10. Northeast wind around 30 mph. Chance of precipitation is 60%.
Saturday
A 30 percent chance of snow after 9am. Mostly cloudy, with a high near 16.
Saturday Night
A chance of snow before 3am. Mostly cloudy, with a low around 6.

 Detailed forecast for Thompson Pass (mid elevation 2000-4000′)

 
DATE             WEDNESDAY 01/26         THURSDAY 01/27          
TIME (LT)        06    12    18    00    06    12    18    00    06
CLOUD COVER      OV    OV    OV    OV    OV    OV    OV    OV    OV
CLOUD COVER (%)  80    95   100   100   100   100   100   100    95
TEMPERATURE      19    25    24    21    21    22    20    16    15
MAX/MIN TEMP                 25          20          23          14
WIND DIR          S     E    NE    NE    NE    NE    NE    NE    NE
WIND (MPH)        3     6     8     9    14    18    19    19    17
WIND GUST (MPH)              28    28    34                      35
PRECIP PROB (%)  40    60    70    80    90    90    80    80    70
PRECIP TYPE       S     S     S     S     S     S     S     S     S
12 HOUR QPF                0.10        0.24        0.46        0.26
12 HOUR SNOW                0.9         3.3         6.9         4.3
SNOW LEVEL (KFT)0.0   0.0   0.0   0.0   0.1   0.0   0.0   0.0   0.0
 

Snow and Temperature Measurements

 

Date: 01/26 24 hr snow  HN24W* High Temp Low Temp Weekly SWE (Monday- Sunday) January Snowfall Season Snowfall HS (Snowpack depth)
Valdez 52 135 41
Thompson Pass N/O  N/O 30 26 76 241 41
46 Mile Trace 37 25 .08 36 65**  24

 

All snowfall measurements are expressed in inches and temperature in Fahrenheit. 24 hour sample period is from 6am-6am. 

* 24 hour snow water equivalent/ SWE.

** Season total snowfall measurements for 46 mile began December 1st.

 

Season history graphs for Thompson Pass

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Click on links below to see a clear and expanded view of above Season history graphs

 

TP WX Nov 21

 

TP wx Dec 21

 

TP wx as of 1/6

Additional Information

Winter weather began early this season, with valley locations receiving their first snowfall on the last day of Summer (September 21st).  Following this storm, above average temperatures and wet weather occurred from late September through early November.  During this time period Thompson Pass received 96 inches of  snowfall by November 7th and Valdez recorded 7.73″ of rain.  

After the 7th of November our region experienced a sharp weather pattern change.  Temperatures dropped below seasonal norms and snowfall became infrequent.  Between the time frame of November 7th- November 28th Thompson Pass only reported 19″ of snow with 1.1″ of Snow water equivalent (SWE).  Temperatures remained below 0° F for most of the period.   This cold/dry weather caused significant faceting of the snowpack, with poor structure the result.

Moderate snowfall returned to our area the last day of November and deposited 6-12 inches of new snow.  The amount varied depending upon the locations’ proximity to the coast.  As the storm exited on the 2nd of December it was quickly replaced by moderate to strong northeast winds.  

On 12/5-12/6 Valdez received 2 feet of new snow with Thompson Pass reporting 16″.  Blaring red flags like collapsing, shooting cracks and propagation in stability tests were immediately present.  On 12/8 a significant remote/ sympathetic avalanche event occurred from Gully 1 through Nick’s Happy Valley. 

Strong outflow winds began on 12/11 with periods of light snowfall.  This has caused slab thicknesses to become variable in areas exposed to NE winds.

A fair amount of natural avalanche activity occurred during the 12/11 wind event mostly on southerly aspects.  The week following this wind event fairly benign weather occurred which allowed the snowpack to adjust and for stability to improve although snowpack structure has remained poor.  

On 12/21 our area received a couple inches of snow along with temperatures rising and strong outflow winds.  This combination of weather kicked off a fairly significant natural avalanche cycle.  Many of the slabs appeared to be deeper wind slabs that were created from the 12/11 wind event.  These failed on faceted snow created in November.  The event is yet another indicator of our poor snowpack structure and its inability to receive any major change in weather without the avalanche hazard rising in conjunction.

 

On 12/26-28 warm air moved in at elevation and caused light rain to fall up to ~4000′.  A very thin rain crust was formed in many locations that was unable to support a persons weight.

 

A prolonged period of strong north winds began on new years day with wind speeds reaching 80 mph.   As winds tapered to 30-40 mph on the 5th temperatures plummeted with lows exceeding -30 F in the Tsaina valley.

 

Snowfall returned to our area on 1/13 with a foot of snow reported on Thompson Pass.  An additional ~6 inches of snow were received on 1/15 with settled storm totals of 2.5 feet above 5000′.  

Moderate outflow winds kicked up on 1/16, but were short-lived and not wide spread.  This was followed by two days of calm and mild weather.

 

On 1/21 a big pattern change occurred with several large Pacific storms delivering rain up to 3000′ and heavy snowfall above.

Announcements

The avalanche hazard is considerable above 2000′, and moderate below.   The main concern today will be fresh wind slabs formed by moderate southeast wind.  The most likely place to encounter these will be the lee sides of ridge lines and cross loaded gullies.  Human triggered avalanches are likely 1-3 feet deep in specific locations.  Decreasing temperatures are beginning to refreeze a previously rain soaked snowpack and lowering the avalanche hazard  at low elevations.  

 

 

Click the + Full Forecast button below for a list of current avalanche problems, travel advice, weather resources and more.

 

Help to improve your local avalanche center and contribute an observation to the website.  You can also contact me directly at [email protected] (907) 255-7690.