Portage/Placer: Skiers triggered two small but wide-propagating avalanches, suspected to be on a weak layer of surface hoar and stellars buried 1-1.5′ deep. They also saw a natural avalanche that they thought had stepped down to the same weak layer on Byron (photo below).
|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|
Wind slabs are once again the primary concern today, as moderate southwest to southeasterly winds overnight and early this morning will build a fresh round of small but reactive wind slabs with the low-density snow that was on the surface yesterday. The key terrain features to watch out for will be steep slopes near ridgelines, convex rollovers, and steep gullies. Because the soft snow on the surface is so light, it won’t take much wind to move it around. This was the case yesterday in the Summit Lake area, where we noticed snow blowing off some ridgelines with weather stations only registering winds at 5-10 mph. Luckily this problem is relatively easy to identify and thus avoid. Be on the lookout for stiffer snow on the surface, and pay attention to warning signs like shooting cracks, collapsing, and fresh avalanche activity. This will require taking a few seconds to hop off your machine or step off the skin track and poke around in the snow to see how it feels. If you are trying to get on steeper terrain, be sure to follow safe travel protocols. This includes only putting one person at a time on steep slopes and watching your partners from safe spots out of the way of avalanche hazard.
We might see a slight increase in winds late this afternoon, especially at the higher elevations. Pay attention to changing conditions, with the potential for more sensitive wind slabs developing if the winds do pick up even a little bit. Keep an eye out for blowing snow along ridgelines as well as the red flags mentioned above.
Cornices: Strong winds over the past week have created very large cornices. Skiers reported natural avalanche activity triggered by a cornice fall up Virgin Creek earlier in the week (details here), and we have seen debris from cornice falls throughout the area. Be sure to give cornices plenty of space if you are travelling along ridgelines, and limit the time you spend below them.
Loose Dry Avalanches: Sluffs will run fast on steep terrain with soft snow sitting on top of firm surfaces left from last week’s strong winds. These are unlikely to bury a person, but can be dangerous if they were to carry you over consequential terrain like rocks, cliffs, or trees.
Debris from an avalanche triggered by a natural cornice fall up Virgin Creek earlier in the week. Photo: Peter Ostroski. 02.11.2022
For some time now we have been mentioning the potential for deeper avalanches failing on layers of facets surrounding crusts from New Year’s and all the way back to the Halloween storm. These layers are concerning in areas with a thinner snowpack, which are most likely found on the fringes of our advisory area (Lynx Creek, Silvertip Creek, Crow Pass area) and outside of the advisory are in Summit Lake. We saw natural and human-triggered avalanches failing on these layers during the strong wind event in the middle of last week (details here), and have found concerning snow pit results over the past few days in the Crow Creek and Summit Lake areas. The same layers have not given any cause for concern recently in the rest of the Turnagain, Placer, and Girdwood areas. Keep this distribution in mind, especially if you are planning on getting out in the zones that have thinner and more problematic snowpack. Without a big loading event, these layers will be stubborn to trigger, but the potential is still there. This requires adjusting terrain accordingly, and avoiding steep and consequential slopes for the time.
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Yesterday: High temperatures were in the mid 20’s to mid 30’s F under broken skies with some sun poking through periodically. Brief rounds of light snow brought a trace throughout the area, with light winds at 5-10 mph and gusts of 10-20 mph from the southwest during the day trending easterly later in the afternoon and overnight. Low temperatures were in the 20’s F.
Today: It is looking like another round of quiet weather is on tap for our area today, with light winds out of the south in the morning trending westerly later in the day. Sustained speeds are expected at 5-10 mph near ridgetops with gusts of 10-15 mph this morning backing off during the day and picking up again late in the afternoon and early this evening. Skies should be mostly cloudy with some sun making an appearance. Some periods of light snow may bring a trace of accumulation.
Tomorrow: Mostly clear skies overnight will allow temperatures to drop into the low teens, along with calm to light winds out of the west. Cloud cover increases during the day tomorrow, and chances for precipitation start to pick up late in the day. It is looking like the next round of precip will once again hit harder to the north of us, favoring the Hatcher Pass area, but we can expect to see around 3-5″ overnight Monday with snow to sea level. Daytime high temperatures will be in the 20’s F.
PRECIPITATION 24-hour data (6am – 6am)
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||31||0||0||90|
|Summit Lake (1400′)||25||0||0||38|
|Alyeska Mid (1700′)||32||tr||tr||90|
RIDGETOP 24-hour data (6am – 6am)
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||25||SE||4||16|
|05/17/22||Turnagain||Avalanche: Sunburst||CNFAIC Staff|
|05/17/22||Turnagain||Observation: Tincan Ridge||Joe Kurtak|
|05/11/22||Turnagain||Avalanche: Cornbiscuit and Magnum west faces||CNFAIC Staff Forecaster|
|05/07/22||Turnagain||Observation: Granddaddy||Kit Barton|
|04/29/22||Turnagain||Observation: Sunburst wx station||AS/ MM/ AM/ NH|
|04/28/22||Turnagain||Observation: More Turnagain Pass/Summit Lake wet slab activity||Alex Marienthal|
|04/27/22||Turnagain||Observation: Magnum||Sykes / Buttrick Forecaster|
|04/27/22||Turnagain||Observation: Girdwood/Summit/Turnagain Road obs||A S|
|04/24/22||Turnagain||Avalanche: Seattle Ridge – large glide avalanche on Repeat Offender path||CNFAIC Staff Forecaster|
|04/24/22||Turnagain||Avalanche: Seattle Ridge uptrack||Martin Schmidt|
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.