|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|
Wet Loose: Spring is here and with it comes daily fluctuations in the avalanche danger with sun and warming. Timing is everything. Clear skies overnight have created a surface crust adding strength to the snow. As the day heats up and the crust melts and loses strength, the danger rises – making it possible to trigger a wet avalanche on steep sun exposed terrain features. Today looks similar to yesterday with daily temperatures expected to reach the mid-40F’s by early afternoon and little to no wind. Remember solar noon is around 2pm and this is when wet avalanches can begin to release, either naturally or by a person. Once the snow becomes wet and ‘mushy’ and your skis or snowmachine start trenching into wet snow, it’s time to find supportable surfaces. Even a small wet avalanche can turn into something larger in bigger terrain.
Wet Slab: There remains some uncertainty around the possibility of triggering a wet slab avalanche as warm temps today make the snow wet in the mid elevations. Earlier this week many natural wet loose and wet slab avalanches occurred below 2000′ where rain saturated the snowpack. As water drains out of the snow and we experience several days of re-freezing overnight this is becoming less likely, but not out of the question.
Cornices: Daily warming and sunnier weather can make cornices more unstable. As always, give cornices plenty of space and limit exposure underneath them.
Widespread natural wet avalanche cycle occurred below 3000′ throughout our region. Note the wet slab at 1500′ on South face of Tincan.
Pay attention to how supportable the snow feels in the afternoon as surface crust melt and the snow becomes wet. Yesterday it was easy to post hole up to your waist on Southerly aspect below 2000′.
Most of the large wet avalanche from 4/10-4/11 on Seattle Ridge were on the Southern end of Turnagain Pass where a generally thinner snowpack exists. Some of these avalanches released near the ground.
Triggering a lingering storm slab or a persistent slab is becoming less likely with time. However afternoon warming adds an element of uncertainty as surface crusts break down and destabilize the snow on solar aspects. Yesterday a group of 3 skiers experienced a collapse (whumpf) at 3000’ on a SW aspect of Tincan, and the day before a skier triggered a storm slab on a West aspect of Johnson Pass near 4900’. We know of older weak snow (facets) buried within the top 2’ of the snowpack and we don’t have a lot of info about how this snow is adjusting in the upper elevations. Northerly aspects with dry snow (without a surface crust) may harbor this set up. Basically triggering slab avalanche 1-2’ deep should still be on your mind if venturing into steeper terrain in upper elevations.
Yesterday was clear and sunny and no precipitation was recorded. Temperatures reached 50F near sea level and mid 40F’s in the mid elevations. Ridgetops were in the mid 30F’s during the heat of the day. Temperatures crept into the upper 20Fs at ridge tops and mid 30F’s at lower elevations. Winds were light from the Northwest 5-15mph.
For today expect sunny skies and another warm day. Temperatures should again reach the low 50F below 1000′ and 40F’s along ridgelines. Winds will be calm to light (0-10mph) from the NW. Temperatures are expected to be in the low 30F’s overnight.
For Sunday and Monday sunny weather will remain with diurnal temperatures swings, cooling overnight and warming during the day . Ridgetop winds are supposed to remain light from the Northwest. There is a possibility for light rain starting Wednesday associated with a low-pressure developing near the Aleutians.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||41||0||0||68|
|Summit Lake (1400′)||37||0||0||24|
|Alyeska Mid (1700′)||40||0||0||65|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||*N/A||NW||5||21|
|04/21/21||Turnagain||Observation: Sunburst||Schauer/ Behney Forecaster|
|04/19/21||Turnagain||Avalanche: Triangle, Seattle creek||Will Morrison|
|04/18/21||Turnagain||Avalanche: Turnagain Pass Road Obs||Andy Moderow|
|04/18/21||Turnagain||Observation: Seattle Ridge, approximately 300 yards south of the up track||Brent Byrne|
|04/17/21||Turnagain||Avalanche: Road obs||Johnston-Bloom / Moderow Forecaster|
|04/16/21||Turnagain||Avalanche: Seattle Ridge||Wendy Wagner Forecaster|
|04/16/21||Turnagain||Avalanche: Turnagain Pass, non-motorized side seen from Seattle Ridge||CNFAIC Staff Forecaster|
|04/16/21||Turnagain||Observation: Sunburst||Lance breeding|
|04/15/21||Turnagain||Observation: Tincan||Schauer/ Rothman Forecaster|
|04/13/21||Turnagain||Observation: Turnagain Pass Road Obs||A Schauer Forecaster|
Status of riding areas across the Chugach NF is managed by the Glacier and Seward Ranger Districts, not avalanche center staff. Riding area information is posted as a public service to our users and updated based on snow depth and snow density to prevent resource damage at trailhead locations. Riding area questions contact: firstname.lastname@example.org
|Area||Status||Weather & Riding Conditions|
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.