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ARCHIVED - Forecasts expire after 24 hours.
Issued
Mon, January 8th, 2024 - 7:00AM
Expires
Tue, January 9th, 2024 - 7:00AM
Forecaster
Andrew Schauer
Avalanche risk The Bottom Line

The avalanche danger is CONSIDERABLE above 1000′. The weather should be mild today but the storm that finished last night brought 1.5-2 feet of snow that will still be sensitive to human triggers today. Don’t let the quiet weather fool you- it is still likely a person can trigger a large avalanche 2-4′ deep within new and windblown snow. Choose terrain carefully today, and keep the big objectives on hold while we wait once again for all of this new snow to settle.

The danger will be MODERATE below 1000′, where lower snow totals make the potential size of avalanches much smaller, and the odds of triggering avalanches a little lower.

Special Announcements

There will be intermittent traffic delays Monday January 8th, 2024 for Avalanche Hazard Reduction work from mileposts 90 to 100 on the Seward Highway, between Girdwood and Bird. Motorists should expect delays of up to 45 minutes between 9:00 am and 12:00pm. Updates will be posted on the 511 system.  http://511.alaska.gov/

Girdwood Forecaster Chat – Friday, Jan 19th! Mark your calendars for Andrew Schauer’s discussion on the different shades of MODERATE danger at the Girdwood Brewing Co. (6:30pm Jan 19). More details HERE.

Mon, January 8th, 2024
Alpine
Above 2,500'
3 - Considerable
Avalanche risk
Treeline
1,000'-2,500'
3 - Considerable
Avalanche risk
Below Treeline
Below 1,000'
2 - Moderate
Avalanche risk
Tue, January 9th, 2024
Alpine
Above 2,500'
3 - Considerable
Avalanche risk
Treeline
1,000'-2,500'
2 - Moderate
Avalanche risk
Below Treeline
Below 1,000'
1 - Low
Avalanche risk
Tue, January 9th, 2024
Alpine
Above 2,500'
3 - Considerable
Avalanche risk
Treeline
1,000'-2,500'
2 - Moderate
Avalanche risk
Below Treeline
Below 1,000'
1 - Low
Avalanche risk
0 - No Rating
1 - Low
2 - Moderate
3 - Considerable
4 - High
5 - Extreme
Avalanche risk Avalanche risk Avalanche risk Avalanche risk Avalanche risk
Travel Advice Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Dangerous avalanche conditions. Careful snowpack evaluation, cautious route-finding, and conservative decision-making essential. Very dangerous avalanche conditions. Travel in avalanche terrain not recommended. Extraordinarily dangerous avalanche conditions. Avoid all avalanche terrain.
Likelihood of Avalanches Natural and human-triggered avalanches unlikely. Natural avalanches unlikely; human-triggered avalanches possible. Natural avalanches possible; human-triggered avalanches likely. Natural avalanches likely; human-triggered avalanches very likely. Natural and human-triggered avalanches certain.
Avalanche Size and Distribution Small avalanches in isolated areas or extreme terrain. Small avalanches in specific areas; or large avalanches in isolated areas. Small avalanches in many areas; or large avalanches in specific areas; or very large avalanches in isolated areas. Large avalanches in many areas; or very large avalanches in specific areas. Very large avalanches in many areas.
Recent Avalanches

We triggered small wind and storm slab avalanches on Notch Mtn. on short but steep rollovers yesterday in the middle of the storm. Multiple large natural avalanches were also reported along the Seward Highway, and it is likely there was more natural activity that went unobserved in the middle of the storm. Hopefully we will get a better sense of the extent of this cycle over the next few days.

Small skier-triggered storm slab on a short but steep rollover on Notch Mtn. 01.07.2024

Avalanche Problem 1
  • Storm Slabs
    Storm Slabs
  • Aspect/Elevation
  • Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic (D4-5)
    Very Large (D3)
    Large (D2)
    Small (D1)
    Size
Storm Slabs
Storm Slab avalanches are the release of a cohesive layer (a slab) of new snow that breaks within new snow or on the old snow surface. Storm-slabs typically last between a few hours and few days (following snowfall). Storm-slabs that form over a persistent weak layer (surface hoar, depth hoar, or near-surface facets) may be termed Persistent Slabs or may develop into Persistent Slabs.
Aspect/Elevation of the Avalanche Problem
Specialists develop a graphic representation of the potential distribution of a particular avalanche problem across the topography. This aspect/elevation rose is used to indicate where the particular avalanche problem is thought to exist on all elevation aspects. Areas where the avalanche problem is thought to exist are colored grey, and it is less likely to be encountered in areas colored white.
Likelihood of Avalanches
Terms such as "unlikely", "likely", and "certain" are used to define the scale, with the chance of triggering or observing avalanches increasing as we move up the scale. For our purposes, "Unlikely" means that few avalanches could be triggered in avalanche terrain and natural avalanches are not expected. "Certain" means that humans will be able to trigger avalanches on many slopes, and natural avalanches are expected.
Size of Avalanches
Avalanche size is defined by the largest potential avalanche, or expected range of sizes related to the problem in question. Assigned size is a qualitative estimate based on the destructive classification system and requires specialists to estimate the harm avalanches may cause to hypothetical objects located in the avalanche track (AAA 2016, CAA 2014). Under this schema, "Small" avalanches are not large enough to bury humans and are relatively harmless unless they carry people over cliffs or through trees or rocks. Moving up the scale, avalanches become "Large" enough to bury, injure, or kill people. "Very Large" avalanches may bury or destroy vehicles or houses, and "Historic" avalanches are massive events capable of altering the landscape.

Signal Word Size (D scale) Simple Descriptor
Small 1 Unlikely to bury a person
Large 2 Can bury a person
Very Large 3 Can destroy a house
Historic 4 & 5 Can destroy part or all of a village
More info at Avalanche.org

Yesterday’s storm brought another round of intense snowfall and strong winds to the area, delivering 1.5-2′ snow in 24 hours starting Saturday night through Sunday night. Since the snow started Saturday night, stations are showing 1.5″ of snow water equivalent (SWE) at Turnagain Pass and up to 2.7″ in Girdwood. The rain line crept up to around 800′ at the beginning of the storm, but dropped to near sea level before it finished. Winds peaked yesterday morning, with a four hour window of recorded wind speeds between 99 and 102 mph on Sunburst ridge between 2 am and 6 am yesterday.

We’re expecting much milder weather today, with light easterly winds and maybe some scattered snow showers. Don’t let the quiet weather fool you– avalanche conditions remain dangerous and there is still a good chance that person can trigger a big avalanche. These quiet periods immediately after a storm are the times when avalanche accidents happen. Anticipate dangerous avalanche conditions today, and plan your day accordingly. With light winds and little to no precipitation expected, we’re not expecting to see natural avalanches today so the avalanche danger won’t be as obvious as it was yesterday. Keep your objectives modest, and your terrain choices conservative. With two feet of new snow on the ground, the skiing and riding conditions should be very good today. This is the kind of day to enjoy the new snow in low-angle terrain, and give it a little time to settle out before venturing into the steeps.

Deeper avalanches: The layer of weak, faceted snow that got buried with last week’s storm is the wild card. We’re not expecting it to be exceptionally reactive, but we will be assessing this over the next few days to make sure we don’t get caught off guard. For now, treat that layer with a little extra caution and be aware of the smaller possibility of very large avalanches failing on that layer.

We went up to Notch Mtn. yesterday to make sure the storm was arriving as scheduled, and we were not disappointed. We’re expecting a calmer day today, but conditions will remain dangerous with all of the new snow. Photo: Rich DiJulia, 01.07.2024

Avalanche Problem 2
  • Glide Avalanches
    Glide Avalanches
  • Aspect/Elevation
  • Certain
    Very Likely
    Likely
    Possible
    Unlikely
    Likelihood
  • Historic (D4-5)
    Very Large (D3)
    Large (D2)
    Small (D1)
    Size
Glide Avalanches
Glide Avalanches are the release of the entire snow cover as a result of gliding over the ground. Glide avalanches can be composed of wet, moist, or almost entirely dry snow. They typically occur in very specific paths, where the slope is steep enough and the ground surface is relatively smooth. They are often proceeded by full depth cracks (glide cracks), though the time between the appearance of a crack and an avalanche can vary between seconds and months. Glide avalanches are unlikely to be triggered by a person, are nearly impossible to forecast, and thus pose a hazard that is extremely difficult to manage.
Aspect/Elevation of the Avalanche Problem
Specialists develop a graphic representation of the potential distribution of a particular avalanche problem across the topography. This aspect/elevation rose is used to indicate where the particular avalanche problem is thought to exist on all elevation aspects. Areas where the avalanche problem is thought to exist are colored grey, and it is less likely to be encountered in areas colored white.
Likelihood of Avalanches
Terms such as "unlikely", "likely", and "certain" are used to define the scale, with the chance of triggering or observing avalanches increasing as we move up the scale. For our purposes, "Unlikely" means that few avalanches could be triggered in avalanche terrain and natural avalanches are not expected. "Certain" means that humans will be able to trigger avalanches on many slopes, and natural avalanches are expected.
Size of Avalanches
Avalanche size is defined by the largest potential avalanche, or expected range of sizes related to the problem in question. Assigned size is a qualitative estimate based on the destructive classification system and requires specialists to estimate the harm avalanches may cause to hypothetical objects located in the avalanche track (AAA 2016, CAA 2014). Under this schema, "Small" avalanches are not large enough to bury humans and are relatively harmless unless they carry people over cliffs or through trees or rocks. Moving up the scale, avalanches become "Large" enough to bury, injure, or kill people. "Very Large" avalanches may bury or destroy vehicles or houses, and "Historic" avalanches are massive events capable of altering the landscape.

Signal Word Size (D scale) Simple Descriptor
Small 1 Unlikely to bury a person
Large 2 Can bury a person
Very Large 3 Can destroy a house
Historic 4 & 5 Can destroy part or all of a village
More info at Avalanche.org

We’re still alarmed with the rate of activity with the ongoing glide cycle in the area. We have no idea if there were any more glide avalanches during yesterday’s storm, but there has been constant glide activity for over two weeks now. These avalanches are large and destructive, and it is impossible to predict the timing of a glide release for a given slope. Be sure to limit your exposure by spending as little time as possible under open glide cracks. We’ve seen many places where glide cracks are opening and releasing over common up tracks on the Seattle Ridge side of the pass, and common skin tracks on the skier’s side. If you notice a glide crack above a route you normally use, consider an alternate route whenever possible. If you can’t avoid the crack entirely, be sure to reduce your risk as much as possible by moving quickly and only exposing one person at a time to routes that travel below open cracks.

 

Weather
Mon, January 8th, 2024

Yesterday: We saw a strong system move through yesterday, bringing 1.5-2’ of snow in 24 hours starting around midnight Saturday night. Rain levels reached as high as around 800’ yesterday morning, dropping to near sea level before the precipitation finished. Winds peaked yesterday morning, with averages of 50-70 mph at ridgetops and 4 hours of gusts between 99 and 102 mph between 2 am and 6 am yesterday. Things calmed down just after sunset as precipitation tapered off and winds calmed down to 5-15 mph. High temperatures were in the mid 20’s to upper 30’s F with lows in the high teens to high 20’s F.

Today: We should see mostly quiet weather today, with some lingering scattered showers possible closer to the coast under partly to mostly cloudy skies. Winds will be out of the east at 5-15 mph with gusts of 10-20 mph. High temperatures will be in the mid to upper 20’s F with lows dropping into the low teens to 20 F.

Tomorrow: Expect to see a shift to a northwesterly flow tomorrow into Wednesday. It is looking like the northwesterly outflow winds should be mild for most of the advisory area at 10-20 mph, but Seward might be the exception with stronger winds of 20-30 mph and gusts of 40-50 mph.

PRECIPITATION 24-hour data (6am – 6am)

Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 27 20 1.2 100
Summit Lake (1400′) 24 3 0.3 N/A
Alyeska Mid (1700′) 29 18 1.48 94
Bear Valley – Portage (132′) 34 1 1.15 –
Grouse Ck – Seward (700′) 34 2* 0.2* 53

*Observations suggest Seward received 1-2 feet of snow at upper elevations that was not recorded at the Grouse Creek snotel.

RIDGETOP 24-hour data (6am – 6am)

Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 21 ENE 25 88
Seattle Ridge (2400′) 24 SE 9 36
Observations
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This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area. This advisory does not apply to highways, railroads or operating ski areas.
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