Avalanche Advisory for 2016-03-24 06:57:13

Variable and transitional are a couple words that I've heard from different local skiers and riders who have been getting out the past few days. The week started off with a decent dollop of snow, 7-12 inches recorded over most of the forecast area. It was followed by cool temperatures that struggled to get above freezing. Yesterday and today were much warmer and the warm temperatures have consolidated the snow another 2-3 inches. The avalanche hazard continues to diminish. No recent avalanches/signs of instability have been reported or observed. On shaded, northerly aspects, powder can be found if free from wind and any solar. Once in the open however, variable supportable crust held decent skiing once a little bit of sun hit it. Below treeline and most lower elevations, a widespread supportable crust about 1 inch thick exists on southerly aspects. In the alpine areas, near and above treeline, wind has done its work by scouring ridgelines to old, hard snow/ice and created wind packed powder in bowls. Small to large sastrugi features can be found also, dispersed above treeline.

In the Castle Lake area yesterday, a few broken cornices off the ridge line were noted, as well as one small point release slide from earlier this week. For today, the main concern is for newly formed wind slabs above treeline on Mt Shasta. Both yesterday and this morning, northwest winds were cranking across the mountain and as mentioned, a giant plume of billowing snow could be seen off of Casaval Ridge while cruising down Interstate 5. What is the best sign of wind loading? Visible blowing snow! So... all leeward ridgelines above treeline, little pockets around chutes, rock outcroppings or any other feature that could create a wind eddy and allow for new wind blown snow to stack up... that is your concern today. These little pockets could be triggered by a skier or rider. The size of these wind pockets could be very small to medium in size, certainly enough to bury a person. Most slopes in the forecast area are going to be free of worry, but once you start to get into steeper terrain where wind loading has occurred, especially on Mt Shasta, be careful. Again, winds have been northwesterly, so slopes SW-S-SE-E-NE facing should be where most wind loading has taken place.

Loose wet related instabilities are a possibility at lower elevations today but not expected to be a major concern as a bit of cloud cover and moderate temps will keep most of the snow in place. That said, we are on the forefront of spring and loose wet avalanches will become a concern in the coming future.

Mt Shasta, viewed from the top of the Castle Lake area on 3.23.16 - Photo: J Koster

The Castle Lake area from below, 3.23.16, with small point release visible. Photo: J Koster

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.