Avalanche Activity

In the past two days our region has seen a large amount of snowfall in short period of time and more snow is expected today and into the weekend. Strong storm force winds have also been a big factor and yesterday numerous large and very large natural avalanches were observed across the region. We urge backcountry users to avoid avalanche terrain -slopes steeper than 30 degree and all runout zones. Today’s weather is variable across the region with Turnagain Pass expecting 6-12” of new snow and Girdwood and Portage Valley 1-3 ft. In addition strong ridgetop winds will continue to actively load leeward slopes throughout the day. Expect Easterly winds to range from 30-40 mph increasing into the 60s mph this evening. Temperatures have remained above freezing at sea level. Expect rain/snow line around ~1000 ft. Wet avalanches are likely below treeline in Portage Valley and summer trails with avalanche terrain above should be avoided like Byron Trail.

***Today periods of broken skies and partial clearing are a possibility the further you get from the coast. If the sun makes an appearance solar radiation will also be adding stress to the snowpack. This is an additional reason to not get lured into avalanche terrain – even if the skiing/riding conditions are tempting to do so.

• Storm Totals (Wed 9PM – Friday 6am):
• Turnagain Pass 1800’:  36” (3.1” SWE)
• Girdwood-Alyeska Midway 1700’: ~30” (2.25” SWE)
• Summit Lake 1400’: 35” (~3” SWE)
• Portage Valley 70’: 1.75” rain (~3-4 ft in upper elevations)

These snow totals are resting on 2-3 ft of storm snow from last weekend that covered up weak faceted snow and buried surface hoar. Not only is this a recent storm snow an issue, but triggering a deeper instability 3-5+ ft deep is also a serious concern. To compound this situation an active weather pattern will continue for Eastern Turnagain Arm tonight and into the weekend with another powerful storm expected Saturday evening. This means dangerous avalanche conditions will continue through the weekend.

Johnson Pass, Summit Lake and further South 2-3 ft of snow fell in very short period of time (roughly 12 hours) producing numerous large avalanches running full path length. Summit Lake and areas in the interior Kenai Peninsula have a very poor snow structure with variety of old weak layers (facets and buried surface hoar) in the mid and base of the snowpack. Not as much precipitation is expected in this zone today, BUT strong winds will continue to load slopes. Very large natural avalanches are possible and human triggered avalanches are very likely. Expect similar conditions throughout the interior Eastern Kenai Mountain region all the way to Seward.

Forecast produced by Heather Thamm, CFNAIC