Valdez
Above 3,000ftConsiderable
1,500 to 3,000ftConsiderable
Below 1,500ftHigh
Degrees of Avalanche Danger
Avalanche Problems
Problem 1
Temperatures have remained above freezing for most of the last 4 days, with over 3 inches of rain falling in the town of Valdez. This has saturated the snowpack to the point where natural avalanches are likely at low elevations in the Port of Valdez. It is possible that facets at the ground are becoming lubricated and could produce full depth avalanches. Stay clear of avalanche runout zones as avalanches have the potential to run full path. Travel in avalanche terrain below 1500′ in the Maritime zone is not recommended.
Likelihood:
- Almost Certain
- Very Likely
- Likely
- Possible
- Unlikely
Size:
- Historic
- Very Large
- Large
- Small
Trend
- Increasing
- Steady
- Decreasing
Problem 2
Dangerous avalanche conditions continue to exist today. Storm slabs have been building in depth over the past 4 days above freezing line. At this point we are unclear as to how high the freezing line went during the peak heat of the storm. Our snowpack will need time to adjust to its new load. Human triggered avalanches are likely today 1-3+ feet in depth.
The depth of these slabs will vary greatly depending upon the climate zone in which you intend to travel. In our Maritime climate zone storm slabs above 2000 feet could be 3-4 feet deep. On Thompson Pass storm slabs of 2-3 feet deep may be present, and in the Continental zone slabs around 1 foot deep could be encountered. These estimates are based upon the below amounts.
Storm total inches of water since warm up began on 1/21:
Valdez: 3.24 inches
Thompson Pass: 1.8 inches
Continental “46 mile” : .26 inches
Our snowpack will need time to adjust to these storm slabs in all of our forecast zones and the avalanche hazard will remain considerable in the short term. Even though less snow accumulated in the Continental zone, the hazard will still be considerable due to a weaker snowpack being in place. In all three forecast zones, moderate southeast winds on 1/24 has redistributed new snow along high elevation ridge lines and wind channeled terrain. Lee sides of ridge lines, cross loaded gullies and convex terrain will be the most likely areas to trigger an avalanche. Although any large open slopes steeper than 30° should be suspect today.
Small test slopes and hand shear tests are a good and quick way to determine how well new snow has bonded. Cautious route finding and conservative decision making will be necessary for safe travel in avalanche terrain today.
Likelihood:
- Almost Certain
- Very Likely
- Likely
- Possible
- Unlikely
Size:
- Historic
- Very Large
- Large
- Small
Trend
- Increasing
- Steady
- Decreasing
Problem 3
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. 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 rock 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.
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
Detailed forecast for Thompson Pass (mid elevation 2000-4000′)
DATE TUESDAY 01/25 WEDNESDAY 01/26
TIME (LT) 06 12 18 00 06 12 18 00 06
CLOUD COVER OV OV OV OV OV OV OV OV OV
CLOUD COVER (%) 100 90 70 90 95 95 100 100 100
TEMPERATURE 27 28 24 20 19 23 20 17 18
MAX/MIN TEMP 29 18 23 16
WIND DIR SE SE SE SE SE E E NE NE
WIND (MPH) 12 12 8 6 4 4 6 8 10
WIND GUST (MPH) 28
PRECIP PROB (%) 80 70 40 30 50 70 70 80 90
PRECIP TYPE S S S S S S S S S
12 HOUR QPF 0.14 0.04 0.16 0.18
12 HOUR SNOW 1.4 0.0 1.2 2.9
SNOW LEVEL (KFT)0.6 0.4 0.0 0.0 0.0 0.1 0.0 0.0 0.0
Snow and Temperature Measurements
| Date: 01/25 | 24 hr snow | HN24W* | High Temp | Low Temp | Weekly SWE (Monday- Sunday) | January Snowfall | Season Snowfall | HS (Snowpack depth) |
| Valdez | 1 | .37 | 33 | 31 | 1.16 | 52 | 135 | 41 |
| Thompson Pass | ~9 | N/O | 30 | 26 | – | 85 | 250 | 42 |
| 46 Mile | 0 | .03 | 44 | 33 | .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
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 High at low elevation and considerable above 1500′. The snowpack at lower elevations in the Port of Valdez has become saturated to the point where natural avalanches are likely. Travel in avalanche terrain below 1500′ in the Maritime climate zone is not recommended. Above 1500′ Human triggered storm slabs are likely 1-3+ feet in depth.
Click the + Full Forecast button below for a list of current avalanche problems, travel advice, weather resources and more.
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