2/22: – Natural avalanches D2-2.5 on the east face of Mt. Tiekel were observed.
2/21: Multiple natural and human triggered avalanches were observed 2/21.
Natural near the toe of the Worthington glacier.
2/20: Two side by side avalanches were observed on the NW shoulder of the Python buttress ~3500′. Crown 2-300′ across and ~3’+ deep, these slides ran into the flat ~800 vertical feet. These slides were triggered by DOT mitigation work 2/19.
2/20: 2 paths on Three Pigs at mp 42 slid naturally to the middle to lower portion of their aprons, D2.5. Low clouds prevented ability to see what elevation they originated from.
2/20: A Natural avalanche was reported on the north shoulder of Mt Tiekel at ~4500′. Details were limited but the entire slope avalanched and crown was reported to be 2 meters deep. R5-D2.5~.
2/19: A Natural avalanche at 32 mile buried the Richardson higway under 10 feet of snow for ~100′. This caused the highway to close for the majority of the day. Details on the slide were limited due to poor visibility on 2/19.
2/14: Dry loose D1-2 natural avalanches were observed running over the wowie zowie ice climb in Mineral creek.
2/13: Natural and human triggered D1 avalanches were observed in keystone canyon.
2/12: A D3 avalanche at mile post 38 hit the Richardson highway and closed the road. Released on a south aspect in the upper elevation start zones, ~5500′, and stepped down around 4-4500′. Further DOT mitigation efforts on Three pigs and 40.5 mile produced no results.
2/11: Small avalanche observed on NW aspect of Dimond “promise land”, ~5500′ , R1-D1.5, wind loaded pocket just off ridge line.
-Several avalanches observed on steep benches below 2500′ on S aspect hippie ridge around MP 35. Only ran height of bench ~100′, but had long connected crowns suggesting these failed on a Persistent weak layer. Crowns ~2′ deep.
2/10: Skies cleared yesterday, from 46 mile to Thompson Pass very few natural avalanches were seen from the 27 inches of snow that fell from 2/8- 2/10.
2/8: Many full path avalanches were reported running around Valdez glacier lake.
2/6: 2 remote triggered avalanches on RFS at 1800-2000′.
Photo of 1st remote trigger listed
-Natural avalanches observed on south aspect at mile 40, ~1800′, 1-2 feet deep and ~100′ wide. SS-NL-R2-D1.5-O. These were triggered by small snow sluffs.
2/2: Numerous Small pockets of unsupported terrain released naturally in the tsaina valley below 2000′, 2′ deep.
1/27-1/30: Naturals were observed on RFS, N aspect ~6000′,
Avalanches were also observed on -40.5 mile, ~5000′ ,W aspect, 60 m crown
– 2 paths on Three Pigs, ~5000′, SE aspect, ran into the top 1/3 of aprons.
– 3 slides on Billy Mitchell ranging from 3000′-6000′, NW- N aspect. The most significant was on the upper bowl of cry babys, ~5000′, ~200 m crown, 1-2 meters deep.
1/23- Found fresh debris in a gully off point 3848′ behind the airport. D2, ran ~2000′.
~ 1/10- There have been several natural windslabs that have released in the Thompson Pass region:
-South slope of catchers mitt, near 27 mile icefall,~3500′, ~300m wide ,~3′ deep, ran 500′ HS-N-R3-D2.5. Photo shows extent of crown, which may have been bigger and is now filled in by wind transported snow.
2/24- Strong NE winds will continue for our area and will increase in intensity the night of 2/24 with speeds of 65 mph possible at Thompson Pass.
The Thompson Pass Mountain Forecast covers the mountains (above
1000 ft) surrounding Keystone Canyon through Thompson Pass to
This forecast is for use in snow safety activities and emergency
Temp at 1000` 15 F 8 F
Temp at 3000` -9- 4 F -7- 5 F
Chance of precip 0% 0%
(above 1000 FT) 0.00 in 0.00 in
(above 1000 FT) 0 in 0 in
Snow level sea level sea level
Wind 3000` ridges NE 25-40 mph NE 25-45 mph
Thompson Pass “DOT”
HN24W= total water received last 24 hours in inches
Thompson Pass weather history 19/20 season beginning 12/21 through 1/23. Click on links below to see full size image.
TP DEC 19
TP Jan 2020
TP wx chart through 2/19
Strong north east winds will affect our area decreasing surface stability and further stressing weak layers deep within our snowpack.
Our area has received up to 4′ of snow with strong south east- south west winds, and warm temperatures since 2/17.
In areas that have received natural avalanches old instabilities will have been flushed out. In areas that did not slide weak layers deep in the snowpack still exist. These weak layers will be difficult to affect due to their depth, but would produce very large avalanches if triggered.
The amount of new snow that we have received is sufficient to produce large avalanches that fail at the new snow/old snow interface. The new snow will need time to properly bond to the underlying snowpack. This bonding process will take time and large human triggered avalanches will be likely in the meantime. As you venture out into the mountains for the first time after this storm terrain progression will be a very important tool to utilize. Test small slopes with no consequence to assess snow stability before moving out onto steeper slopes.
Forecast Confidence is Low.
Resolution is Low
There have been limited observations from interior locations due to low snow at lower elevations. Use caution if you travel in these areas.
If you see something in the mountains that could contribute to this forecast, leave a public observation. The more observations we receive, the better we can tune our forecast. If you would rather not post an observation publicly, feel free to send me an email at [email protected]
Be aware that the elevation bands have changed on our website. Low is now below 2000′, Mid is 2000-4000′ and high is 4000′ and above.
Send in your best mountain recreation photos to [email protected] so we can post a photo of the week!
Photo of the Week
Thanks to Spencer Byson for sending in this photo!
The avalanche hazard is Considerable at all elevations. Strong north east winds are redistributing significant amounts of new snow onto lee aspect (SE-NW) in areas exposed to outflow winds. Wind slab avalanches 2-4′ deep are likely in terrain steeper than 30° that are receiving active wind loading. Avalanches initiated in the upper snowpack have the potential to step down into deeper layers of the snowpack and create very significant avalanches. Numerous natural and human triggered avalanches have been observed the last 2 days. Avalanches are the number 1 sign of snowpack instability. Be conservative in the mountains today .
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