Archived Avalanche Advisory for Saturday, January 16, 2016 at 6:48 am An avalanche fatality was confirmed on Jan 16, 2016 at Hatcher Pass. Advisories expire after 24 hours from the posting date/time. BOTTOM LINE MODERATE AVALANCHE HAZARD at mid (2500'-3500') to upper (3500’+) elevations on leeward aspects, northeast to west for PERSISTENT SLABS. Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Human triggered avalanches possible, natural avalanches unlikely. Small avalanches in specific areas; or large avalanches in isolated areas. Use caution and practice safe travel protocol on steep slopes and in the runnout of steep slopes, 35° and steeper, around wind loaded pillows, leeward and cross-loaded features and ridges where triggering a slab 1 to 3 feet deep may be possible in isolated locations. LOW AVALANCHE HAZARD at low elevations (below 2500') and out of the runnout of significant avalanche hazards from mid and upper elevations. Generally safe avalanche conditions. Watch for unstable snow on isolated terrain features. Use extra caution around wind loaded terrain traps. LOW DOES NOT MEAN NO HAZARD. RECENT ACTIVITY, CONDITIONS, WEATHER HISTORY No slab avalanches have been reported or observed this week. A few point releases were reported, low volume, which are likely recrystallized surface snow up to 2?- 6? deep which can run moderately fast on the firm, wind-board surfaces underneath. Hatcher has had limited use this week, so slope testing has also been limited. Many old avalanche crowns and debris piles are visible. Surface hoar is prevalent at all elevations and widespread, 2-6mm in size. Some scoured areas have exposed the December rain crust to the surface, other scoured areas contain raised tracks and recrystallized, weak snow on the surface. Some wind board is out there, as well as very firm, slick impenetrable snow with a skim of new snow and surface hoar on top. In the most protected areas, recrystallized, square powder exists up to 6?-10? deep. Overall it’s quite a mixed bag for riding conditions. The snowpack depth is highly variable with either scoured, shallow areas of very rotten, weak old snow or previously wind loaded areas of very thick, firm snow up to 3-5 feet deep, and not much in between. Weather this week at 4500' on the Marmot Weather Station: Temps averaged 24°F. The weekly average wind speed was 7 mph ESE with a max gust of 32 mph. One inch of snow was reported at Independence Mine Snotel this week. AVALANCHE PROBLEM 1 Avalanche activity has settled down substantially since the last avalanche cycle ending January 6th, and the snowpack has improved over time. Hard slabs over weaker snow still exist in many locations, although the continuity of this poor structure is highly variable. This means that in isolated locations you may be able to find poor structure that will be stubborn to react in stability tests, but may be possible to human trigger. Avalanches of this type will likely be smaller in width and mostly limited to pockets of wind loaded snow, and up to 3+ feet deep. Expect this problem on Northeast to West aspects, near wind loaded ridges, gully sidewalls and cross loaded features, at mid to upper elevations, on slopes 35° and steeper. One factor that is playing to our advantage is the thickness of these slabs. In many places, the slabs are 3+ feet deep, and transferring your weight to weak layers at this depth and triggering an avalanche will be difficult. The thickness of these slabs will taper towards the edges of the wind-loads and be weaker around buried and exposed rocks. In these very specific locations, it may be possible to trigger the larger slab that rests above you, below you, or adjacent to you. While the likelihood of triggering an avalanche is not high, the consequence is high. If you travel into the backcountry this weekend, use safe travel protocol to mitigate the hazard, especially on these wind loaded features and areas. AVALANCHE PROBLEM 2 Large cornices exist at upper elevation ridgelines. Give these hazards a wide berth. Approach ridgelines with care to avoid collapsing large, overhanging cornice features. If you are around cornices, be aware that people may be below you and triggering a large cornice could have high consequences. TREND The avalanche hazard will have slow improvement through the weekend.