Cloudy skies, cool temperatures and light winds will not impact avalanche conditions today and a Normal Caution (LOW danger) regime remains in place. The one exception is the glide avalanche. We have seen several small glide cracks release into avalanches in the Girdwood Valley and Turnagain Pass during the past two days. Although many of these slides are on the smaller side and in areas not commonly traveled, there are some current issues on Seattle Ridge. Several cracks have opened up along the ridge and one of these released Friday, Mar 1st. As far as the older glide cracks we’ve been monitoring in popular areas such as Magnum, Lipps, Cornbiscuit, these do not appear to be moving as quick. PSA: Help us keep track of these cracks and send us a photo!
Things to keep in mind if you are headed into the backcountry:
Surface conditions? In general, a stout sun crust has been found on southerly facing slopes. Otherwise, 4-8″ or so of soft re-crystalized (near surface faceted snow) sits over a firmer base on shaded aspects. In anticipation of the next storm, we are closely mapping the surface conditions as well as watching for new surface hoar growth.
The ‘State of the Glide Cracks’ along the front side of Seattle Ridge seen from the motorized parking lot.
South of Turnagain – Summit Lake and Silvertip zones: For anyone traveling in this area note that a shallow snowpack with a generally poor structure exists. A variety of old weak layers (facets and buried surface hoar) sit in the mid and base of the snowpack. It is uncertain as to how reactive these layers are at this point and if they could produce a slab avalanche. We do know whumpfing has been observed in the Summit area and last Thursday’s (2/21) wind event triggered many large slab avalanches breaking in deeper weak layers. Assessing the slab as well as the weak layer will be important. Old wind slabs in steep terrain sitting on weak snow are the most suspect places to trigger an avalanche.
Yesterday: Overcast skies with light easterly ridgetop winds blowing 5-10mph. Temperatures stayed a cool 15-20F in the upper elevations, while lower elevations warmed to the mid 30’sF. Overnight, valley bottoms have only dropped to the upper 20’sF due to cloud cover limiting most radiative cooling.
Today: Cloudy skies with a chance for a few snow flurries will be over the region as a weak low pressure moves overhead. No snow accumulation is expected. Ridgetop winds are forecast to be light and variable. Temperatures along ridgelines should remain in the 15-25F range and lower elevations are likely to warm back into the mid 30’sF.
Tomorrow: A brief ridge of high pressure builds in for Monday. This should clear skies, keep temperatures cool and bring light winds. It will also provide one good visibility day before a large scale trough pushes several fronts over Southcentral bringing periods of snow and wind for the later part of the work week. Stay tuned!
STATE OF THE SNOWPACK: Charts below show both Snow Depth and Snow Water Equivalent (SWE) for Turnagain Pass. Main take home here is Turnagain Pass’s snowpack is just over half (57%) of what it typically is as of March 2nd. Large snowfall events can really help out the pack quickly, as they did last year, and many of us are hoping for a few of these events for March and April 2019!
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||29||0||0||58|
|Summit Lake (1400′)||23||0||0||28|
|Alyeska Mid (1700′)||29||0||0||54|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||26||S||2||8|