Northwest Avalanche Center WA Cascades near and west of crest - north of Stevens Pass Issued: 6:04 PM Friday, January 17, 2014 by D'Amico NWAC avalanche forecasts apply to backcountry avalanche terrain in the Olympics, Washington Cascades and Mt Hood area. These forecasts do not apply to developed ski areas, avalanche terrain affecting highways and higher terrain on the volcanic peaks above the Cascade crest level. The Bottom Line: Watch for wet-loose slides once again on solar aspects. Above Treeline: Moderate Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Near Treeline: Moderate Heightened avalanche conditions on specific terrain features. Evaluate snow and terrain carefully; identify features of concern. Below Treeline: Low Generally safe, watch for unstable snow on isolated terrain features. Avalanche Concerns Loose Wet - Loose wet avalanches occur where water is running through the snowpack, and release at or below the trigger point. Avoid terrain traps such as cliffs, gullies, or tree wells. Exit avalanche terrain when you see pinwheels, roller balls, a slushy surface, or during rain-on-snow events. Wind Slab - Wind slabs can take up to a week to stabilize. They are confined to lee and cross-loaded terrain features and can be avoided by sticking to sheltered or wind scoured areas. Snowpack Analysis: The most recent storm cycle to impact the PNW ended Tuesday after lasting for nearly a week with 2 - 4 feet (60 - 120 cm) of snow for the west slopes. A fair amount of westerly wind accompanied the event from Friday through Monday and redistributed new snow onto lee slopes. The tail end of the storm cycle from Sunday afternoon through early Tuesday was accompanied by a warming trend that brought rain to mid elevations. The main avalanche activity with this cycle occurred last Sunday with large to very large D2 to D3 natural avalanches reported throughout the west slopes with start zones mainly in the near and above tree-line zones on wind loaded aspects. Natural avalanches released within the storm snow with isolated but larger slides up to 5' were produced by local ski patrols with explosives down to older crusts. Tuesday through Friday featured increasing temperatures and sunshine. The warmer and drier weather has allowed for snowpack settlement of about 6-12+ inches since late Sunday. The new storm snow is generally well-bonded. On higher terrain surfaces vary from dense powder on wind and sun sheltered aspects...to chalky wind board on lee slopes...to sun crusts on solar aspects. Due to the low angle this time of year the somewhat supportable rain crust at low and mid elevations on non-solar aspects remains firm during the day. NWAC observer Tom Curtis on Wednesday from Jove Peak reported a sudden collapse and a clean shear in a compression test on an east aspect near-treeline. However, this layer did not propagate in an Extended Column Test but suggests there may still be some touchy but increasingly isolated wind slab on lee slopes. The warm and sunny weather activated solar aspects with large wet-loose avalanches reported Tuesday and Wednesday that ran into the below tree-line zone in the Stevens Pass area. Despite temperatures Friday morning out of the inversion well above freezing most areas reported a healthy re-freeze from radiational cooling. Day-time highs were around 5 F warmer than Thursday but coupled with the low angle mid-Jan sun little wet-loose activity was reported Thursday or Friday on solar aspects. Natural wet loose releases reported near Hurricane Ridge on solar aspects were all D1 or less. A low sun angle and cooler temperatures have diminished the possibility of loose-wet releases on solar aspects below tree-line. For the Olympics and west slopes of the Cascades a generally favorable mid and lower snowpack exists and is expected to consist of crust layers and melt form crystals. The avalanche danger is locally lower in the Olympics where the snowpack on windward and solar aspects near and below tree-line has less snow and ample terrain anchors. Detailed Forecast for Saturday: Solar influences will once again drive the main avalanche danger on Saturday, however, varying amounts of cloud cover, increasing southwest winds in the afternoon and temperatures 5 or more degrees cooler than Friday should help keep the risk relatively lower on Saturday. Watch for a poor re-freeze Friday night as sign of greater than expected potential for wet-loose avalanches. Be aware of quickly softening surface snow in the late morning on solar aspects. Natural pin-wheels or sinking in more than ankle deep means it is time to get off that slope and out of the way of steeper southerly slopes and avoid terrain traps. Continue to approach wind loaded slopes with caution, isolated wind slab may linger on N thru SE aspects near and above treeline zones.