Avalanche Advisory for 2016-03-25 07:01:34

Since the morning of the 23rd, the northwest winds have been howling on the mountain and transporting a lot of snow onto leeward south, southeast, east and northeast aspects. While yes wind loading on these aspects is certain, much of the snow (as visible in the photo below) has also likely been blown away. While it has been windy on the mountain, other locations in the forecast area have been less windy and warmer. The Castle Lake area reported "well done" corn on south and east aspects by 10am yesterday. Temps at Castle rose to 52 degrees and tomorrow they should be even warmer. This has and will create loose wet instabilities like roller balls and pinwheels, with the chance of larger loose wet slides possible. Further observations at Castle Lake noted melting lake edges. This is actually a serious concern... if one gets caught or knocked off their feet in any type of avalanche and the slide makes it's way down to lake level... well, lets just say it's very difficult if not impossible to dig somebody out from underneath slushy water. In other words, melting lake edges are horrible terrain traps! Be careful up there.

On the mountain, the snow is still in a transitional state. Yesterday a local observer toured up to the Sun Bowl area. High winds were obvious due to visible snow transport at all elevations above treeline. South, southeast and east aspects were most notably wind loaded. Winds below treeline were much less, 5 mph/G-15 mph. The snow near and below treeline on southerly aspects was soft and isothermic. Snow on ridgetops, windward slopes and in the shadows remained firm. On the Sun Bowl bench, just above treeline, wind speeds were estimated at a sustained 35 mph with gusts to 40 mph and on Green Butte proper, 50+ mph, northwest. A snowpit on a S/SE slope, 37 degrees,  found a total "new" snow depth of 46cm down to the old snow surface. The upper 4cm of the surface comprised of a crust. Solar radiation has been effective at softening the upper portion of crust but has not been significant enough for a ski to penetrate while making turns. Below the surface crust, lighter density, rounding snow grains exist. The old snow is a bullet proof, knife hardness melt-freeze crust. One ECTN16 test at 17 cm down was due to a density change in the snow from pencil hardness to one finger. While a slab is not expected to fail here, it could be the depth where wet slides may be triggered with Saturday's warming.

Northwest winds on Mt Shasta and snow transport! Photo taken from Mt Shasta City on 3.24.16 by T Belton.

A note for all climbers and skiers heading up onto the upper mountain: Rime ice has formed on most rock outcroppings and is currently very thick. As warm days ensue, rime ice will flake off and fall down onto the slopes below. Rime ice chunks can be very large and very hard, enough to potentially kill you or cause serious injury. Beware of this hazard. Keep your eyes up slope as you climb and move laterally to avoid falling chunks of ice.  If continuous ice fall is encountered turn around and descend to climb another day!

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LOCAL AREA ROAD, NORDIC, AND SNOWMOBILE PARK STATUS:

The Sand Flat cross country ski trails are in good shape and ready for your cross country skis and snow shoes.  These are backcountry routes marked with blue diamonds on trees.  Trails are not groomed.  Snow shoers, please blaze a parallel trail to cross country skiers staying out of the skin track.  These trails can be accessed via the Everett Memorial Highway.  Thank you, and enjoy!

The Mt. Shasta Nordic Center is open! These beautiful, groomed trails can be accessed via the Ski Park Highway. http://www.mtshastanordic.org

The Pilgrim Creek & Deer Mountain Snowmobile Parks are open!  Trails have not been groomed in the past week and a half due to constant deep snow fall.  Head to our "Education" tab on our website and find the snowmobile section for trail information, grooming status, and other sledder resources.

The Castle Lake Road is OPEN. The Everitt Memorial Highway is OPEN. The Castle Lake and Everitt Hwy are plowed year round to the trailheads. The roads are not always first priority, so your dawn patrol powder mission might be ceased if the plow has not made it up yet. Siskiyou County does a great job keeping the roads clear and be respectful of the plow drivers if you encounter them. If you get to Bunny Flat before or during when the plow is there, please park on the uphill, LEFT side of the parking lot as you drive in. This is uphill and lookers right of the bathrooms. Thank You!

The Five Red Flags of Avalanche Danger any time of year include: 1) Recent/current avalanche activity 2) Whumphing sounds or shooting cracks 3) Recent/current heavy snowfall 4) Strong winds transporting snow 5) Rapid warming or rain on snow.