Good morning. This is Wendy Wagner with the Chugach National Forest Avalanche Information Center on Friday, January 27th at 7am. This will serve as 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).
The avalanche danger remains MODERATE for triggering a wind slab avalanche on slopes with recent wind deposited snow. Slabs that formed during yesterday’s moderate winds may still be sensitive to a person’s weight today. Additionally, watch for shallow soft slabs (formed in the denser snow that fell yesterday) that may crack out from you on steeper slopes.
Winds kicked up a bit yesterday for the first time in a couple of days – averaging 20mph and gusting into the 30’s on the Turnagain Pass ridges. One report commented on wind effect and loading in exposed locations above treeline but no avalanche activity has been seen. Obscured skies kept observations limited yet weather stations suggest the wind was more behaved in the Girdwood and Summit areas.
Today, wind slabs, which likely formed yesterday and still sensitive to the weight of a person, will be the primary concern. These are most likely to be found just off the ridgelines, on rollovers and cross loaded near sub-ridges and gullies. Watching for rounded wind pillows and drifts as well as cracking around your snowmachine and board(s) will be the best way to identify these ‘slabs’. Small to medium fresh cornices may be possible to break off today as well.
Areas without wind and below treeline may see some cohesiveness in the upper 4-6″ of the pack from the denser snow that fell yesterday. This has probably settled out in most areas, but where it has not a shallow soft slab could be triggered, yet the slope angle would need to be quite steep. CNFAIC Staffwise, a generally LOW danger exists in areas that have not seen wind effect.
Note: There is scattered buried surface hoar in lower elevation drainages (below 1500-2000′). This is more prominent in the Girdwood Valley and northern side of Turnagain Pass and, what seems to be, less so in the southern Turnagain region. Our investigations yesterday on Max’s Mountain found it moderately reactive around 1500′. Collapsing, but no cracking/avalanching has been seen/reported on this layer to date – yet the layer exists and a person could get a surprise on a lower elevation rollover.
Snow showers covered most of the Girdwood and Turnagain Pass area yesterday with anCNFAIC Staff 4″ of cold (and slightly more dense) snow accumulating. Temperatures were chilly in the single digits and winds picked up from the east, averaging around 20mph and gusting into the 30’s for most of the day at the Sunburst weather station.
Today, the low pressure that has been parked in PWS, which has spilled easterly ridgetop flow our way and allowed for light snow showers, will weaken and move south. Winds have already decreased and are variable around 5-10mph. Skies have cleared overnight and temperatures have dropped to below 0F at almost every weather station this morning. Skies should continue to clear through the day, temperatures will stay cold and light variable winds are expected on the peaks.
CNFAIC Weather Page and the NWS forecast
Kevin will issue the next advisory Saturday morning. If you get out in the backcountry we want to know what you are seeing. Please send us your observations using the button at the top of this page or give us a call at 754-2369. Thanks and have a great day.