ARCHIVED FORECAST - All forecasts expire after 24 hours from the posting date/time.
Thursday January 10th, 2019
Posted by Heather Thamm on 01/10/19 at 7:00 am.
Avalanche risk
The Bottom Line
Low Avalanche Danger
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

A generally  LOW  avalanche danger exists across all elevations bands for the Turnagain area. Triggering a slab avalanche is unlikely but not impossible. Glide cracks may release into avalanches. Limiting/avoiding exposure under them is prudent. Give cornices a wide berth and watch your sluff.

SUMMIT LAKE / JOHNSON PASS / LYNX DRAINAGE: Keep in mind buried weak layers exist in the middle and base of the snowpack. More potential for triggering a large slab avalanche exists in this zone. Choose terrain wisely and please read the Additional Concerns below.  

1. Low
Alpine
/ Above 2,500'
Avalanche risk
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
1. Low
Treeline
/ 1,000'-2,500'
Avalanche risk
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.
1. Low
Below Treeline
/ Below 1,000'
Avalanche risk
Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features.

Special Announcements

Check out our calendar  for upcoming avalanche classes and events in January! Lots of opportunities with all the avalanche education providers in the area.

Avalanche Problem 1
Normal Caution
Normal Caution means triggering an avalanche is unlikely but not impossible.
  • TYPE
    Normal Caution

Despite our generally stable conditions, it is still important to look for signs of instability as the mountains can surprise us at times. Periods of localized ridgetop winds over the last two days have transported some surface snow. Finding an isolated wind slab is not out of the question. The last avalanche triggered was over a week ago and cold temperatures have been helping the snowpack adjust. Observations and snowpack tests have been pointing towards a stabilizing snowpack.

Low danger does not mean no danger. Practice good travel habits, such as exposing one person at a time, watching your partners and grouping up in safe zones are key ways to minimize risk. Ease into steep terrain and factor in the consequences should you encounter one of the following:

  • Glide avalanche:  
    • Identify glide cracks and avoid spending any time under these features. Glide cracks are opening and have avalanched within the last week. Glides are completely unpredictable and not human triggered.
  • An outlier slab avalanche: 
    • Triggering a slab avalanche would most likely occur on an exposed ‘unsupported slope’ that sits above a cliff or steep rocky terrain. A wind slab or a pocket of buried surface hoar 1-3′ below the surface may be lurking in an isolated area.
  • Cornice fall: 
    • Remember cornices often break farther back from ridges than expected. Give them a wide berth.
  • Loose Snow Sluffs:
    • Be aware of fast moving surface snow in steep terrain. Sluffs are slowly becoming larger as the cold weather weakens surface layers.

 Glide cracks and wind textured snow on the SW face of Tincan Proper. Photo taken yesterday 1/9/18 compliments of Allen D. and Eric R. Glide cracks are present in a lot of popular terrain and can be hard to see until you’re suddenly near one.

Additional Concern
Persistent Slabs
Persistent Slab avalanches are the release of a cohesive layer of snow (a slab) in the middle to upper snowpack, when the bond to an underlying persistent weak layer breaks. Persistent layers include: surface hoar, depth hoar, near-surface facets, or faceted snow. Persistent weak layers can continue to produce avalanches for days, weeks or even months, making them especially dangerous and tricky. As additional snow and wind events build a thicker slab on top of the persistent weak layer, this avalanche problem may develop into a Deep Persistent Slab.
  • TYPE
    Persistent Slabs

South of Turnagain – Lynx Creek/Johnson Pass/Summit Lake zone:  A poor snowpack structure exists in these areas. The buried surface hoar that we have been talking about over the past week has been found as well as facet/crust combinations in the bottom of the snowpack. The last avalanche cycle was over a week ago during the New Year’s storm, and overloaded a variety of these weak layers in Summit Lake. Cold weather this weak has been helping stability around the area, but steep slopes without debris below remain suspect. If you’re headed this way, the snowpack becomes more complex – evaluate terrain exposure and the snowpack as you travel.

Mountain Weather

Yesterday: Skies were partly cloudy becoming overcast in the afternoon with a period of light snow showers. A trace of snow was observed. Temperatures were in the teens F in the upper elevations and dropped into the single digits overnight. Valley bottom temps increased from single digits F to teens throughout the day. Ridgetop winds were light 5-15 mph from the NW with a few hours in the 10-20mph range.  

Today: Expect clear skies and single digit temperatures in the upper elevations with slightly warmer valley temps. Temperatures in the alpine are expected to drop into the negative digits by this evening. Ridgetop winds should remain light from the NW winds. No precipitation is expected.

Tomorrow: Clear skies and single digit temperatures will continue through tomorrow before a weather pattern shift on Friday night. A series of fronts associated with a low-pressure system moves into the Gulf of Alaska bringing warm, windy and wet conditions by Sunday.   This is our next chance for snow with rain expected near coastal areas.

*Seattle Ridge weather station was heavily rimed and the anemometer (wind sensor) was destroyed. We are currently working to replace it.  

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

  Temp Avg (F) Snow (in) Water (in) Snow Depth (in)
Center Ridge (1880′) 15   0 0   54  
Summit Lake (1400′)  6 0   0   20  
Alyeska Mid (1700′) 10   trace   0   42  

RIDGETOP 24-hour data (6am – 6am)

  Temp Avg (F) Wind Dir Wind Avg (mph) Wind Gust (mph)
Sunburst (3812′) 8   WNW   5   23  
Seattle Ridge (2400′) 13   *N/A   *N/A     *N/A