The Turnagain, Girdwood and Placer zones have entered the “Normal Caution” regime of backcountry hazards. What this means is triggering an avalanche is unlikely but not impossible. Watch for south facing slopes to become wet and punchy by the afternoon and keep in mind the following:
Today will be the 7th day of sunny and springtime weather. The warmest day so far was Monday 2/25 and today looks similar. Several wet loose avalanches were seen on South facing steep rocky slopes, like this photo of a mountain near Portage Valley. Keep close tabs on how the snow surface is heating up during the day.
Surface crust on steep Southern aspects is 1cm to 1″ thick. If this crust becomes wet and saturated avoid steep South aspects.
South of Turnagain – Summit Lake/Silvertip/Johnson Pass zones: A shallow snowpack with a generally poor snowpack structure exists in these areas. A variety of weak layers sit in the mid and base of the snowpack and were re-activated last Thursday by the outflow wind event. Many natural avalanches were seen on windloaded slopes in the Summit Lake area. Although whumpfing has been observed in the Summit area, no signs of instability may be encountered before a slab is triggered.
Again a quick recap of the weak layers sitting in the pack:
Valentine’s Layer: Small facets, 10″-16″ deep, last avalanches on 2/21 due to wind event region-wide. Not showing signs of reactivity in Turnagain/Girdwood/Placer currently. Layer was responsible for the 2/19 snowboarder remotely triggered slab on Seattle Ridge.
MLK Jr Layer: Buried surface hoar, 2-3′ deep, last avalanches seen in this layer 2/21 in the Summit Lake region. All natural slides.
Basal facets (large faceted snow near the ground): This layer has only been found in the Summit Lake region and produced at least one very large natural avalanche on Thursday, 2/21.
If you’re headed this way, remember the snowpack becomes more complex – evaluate terrain exposure and the snowpack as you travel.
Yesterday: Skies were clear and sunny. Winds were light from the Northwest. No precipitation fell. Temperatures were inverted, teens F rising to low 20Fs in valley bottoms with daily warming. Temps along ridge tops were in the upper 20s F rising to low 30s with daily warming. Overnight ridge top temperatures have been on the rise. Sunburst weather station temps have been above freezing 32F since midnight. Lower elevation temps have dropped into the single digits F and low teens F at sea level.
Today: Another clear and sunny day is in the forecast with high pressure centered over the Gulf of Alaska. The only difference today is temperatures are expected to be warmer, especially in the upper elevations. Temperatures are already at 34F at Sunburst and may rise to the upper-30s F. Sun and daily warming will cause inverted temperatures at sea level to climb into the 30s F. Winds will be light and variable.
Tomorrow: Looks similar with another day of clear and sunny weather. Unusually warm temperatures will persist through tomorrow. Highs at ridge tops will be in the mid 30s to low 40s F. Overnight temps will drop into the teens at valley bottoms with warmer temps in the upper elevations. Light and variable winds are expected.
|Temp Avg (F)||Snow (in)||Water (in)||Snow Depth (in)|
|Center Ridge (1880′)||27||0||0||59|
|Summit Lake (1400′)||15||0||0||28|
|Alyeska Mid (1700′)||21||0||0||54|
|Temp Avg (F)||Wind Dir||Wind Avg (mph)||Wind Gust (mph)|
|Seattle Ridge (2400′)||24||N||2||9|