Skyline Avalanche Advisory Friday, March 25, 2011 Created at 5:59 am Forecaster: Grant Helgeson BOTTOM LINE This is a weekend of changing conditions, so riders will need to stay alert to their surroundings. There is currently a Level 2 (Moderate) avalanche hazard for a few different issues: - Loose snow avalanches failing in the new snow, a mostly manageable hazard, - Wind slab avalanches in areas where the new snow is exposed to wind & - The possibility for deep slab avalanches on steep rocky upper elevation slopes facing the north half of the compass. Pockets of Level 3 (Considerable) windslab avalanche danger will exist up high late Friday and into Saturday as strong winds begin to have their way with the new snow forming fresh sensitive wind slabs. CURRENT CONDITIONS Two small fast moving storms this week left us with 12" of new snow. Riding and turning conditions are currently good, and about to get better. It's pretty quiet on the Skyline this morning in anticipation of the coming storm. Temps are in the low 20's and winds are light of the SW. RECENT ACTIVITY Yesterday Steve and I were able to intentionally trigger numerous loose snow avalanches aka sluff's running in the new snow. Yesterday's snow tightened up overnight, but, there's another storm scheduled to arrive mid-day & with it comes a new set of hazards. THREAT #1 It's nearly April and we're expecting 10" - 20" of light density snow this weekend. Events like this are one of the many perks of living in Utah. As you're out there enjoying the new snow, stay alert to how it's behaving. More often than not, new snow is sensitive to human intervention, failing as manageable loose snow avalanches. Add a little wind to the equation though, and you have widespread sensitive wind slabs. So, be aware of your surroundings and be sure to continually tweak small test slopes throughout the day because the theme this weekend is changing conditions. THREAT #2 12" of new snow has fallen this week & another 5" -9" is expected today. Combine that with strong winds forecasted for this afternoon and you've got the perfect recipe for wind slabs. Riders need to keep their game faces on all day, as windslabs will be most sensitive late this afternoon, just as we're starting to feel fatigued. Saturday will bring out the masses, and the wind slab danger will still be an issue, especially up in the wind zone at and above treeline. Take note of how the snow feels under your machine. Light and fluffy is great, but if it starts to feel stiff and slab like then you're getting into wind slab country. Look for the visual clues too: fresh cornice development, fat pillow like formations and shooting cracks all indicate windslab development & the potential for avalanches. THREAT #3 Remember the rain event way back in January? It seems like so long ago now, but the snowpack has the memory of an elephant. There is a unique series of weak layers now buried 3' deep in our snowpack. While the chances of triggering an avalanche failing deep in our snowpack are slim, if you do the consequences are very high. The most likely scene for a deep slab avalanche is a steep rocky slope above treeline. By avoiding slopes like this, we can be sure to avoid a tangle with the deep slab monster. If you decide to jump into the bigger slopes, just remember that there is a small chance of triggering a large and destructive deep slab avalanche. MOUNTAIN WEATHER Get ready for a stormy weekend. A cold front is scheduled to arrive in our neck the woods around lunch time today, bringing 5" - 9" of light density snow with it. Winds begin to ramp up this evening after the storm while temperatures drop into the teens overnight. Temps rise to 30° Saturday & snow begins to fall again Saturday afternoon, continuing into the evening with total accumulations in the 4" -8" range. Sunday brings intermittent flurries as temps warm into the lower 30's. Monday looks to be mostly cloudy skies before things clear out on Tuesday. GENERAL ANNOUNCEMENTS The information in this advisory expires 24 hours after the date and time posted, but will be updated by 7:00 AM Friday, April 1st, 2011 which will be the final advisory of the 2010/2011 season.