Avalanche Advisory for 2015-12-30 06:40:29

Observations made yesterday on a short tour up "T-bar", just below Green Butte and Powder Bowl on Mt. Shasta, revealed continued powder snow conditions in protected areas below treeline.  Reports from those who ventured above treeline were of less ideal conditions resulting from a crust layer on exposed slopes.  No signs of instability were witnessed or reported. Over the course of the previous week several locations throughout the 60 square mile avalanche forecast area were visited with similar snow conditions observed.  Below and near treeline, southerly aspects host a crust of variable depths and thickness with some shaded areas still holding powder. Above treeline, southerly facing, wind blown-icy ridges prevail with softer snow and wind packed powder in the gullies. Northerly aspects below and near treeline are still hosting soft snow, and are the best spots to find good skiing and riding. Consistent cold temperatures have kept our snow amazingly light and fluffy on these colder shaded aspects. The continued great snow conditions have been a real treat considering the past couple of sub-par winters we all have had to endure.

In case you did not get the memo, the persistent weak layer avalanche problem has subsided.  It definitely made for an interesting couple of weeks in our local backcountry.  It is a snowpack issue we typically do not deal with, but appears to have healed itself and will fade into winter history. 

The wind slab avalanche problem could probably always be up on the advisory as Mt Shasta is a big mountain sticking up into the atmosphere and always receiving wind. That said, potentially dangerous wind slabs have been far and few between. We've been able to trigger very small slabs off ridge lines and bowls in steep, complex terrain but these small slabs have been insignificant.  It was just reported to the MSAC this morning that a human triggered wind slab avalanche occurred this past weekend on Sunday (Dec. 27th) in Avalanche Gulch.  The slide was triggered along the convexity at the top of one of the center moraines below 50/50 Flat dropping into Avalanche Gulch proper.  The avalanche propagated from the trigger point resulting in a width of close to 100 feet, and a crown depth of around 12 inches.  The slide traveled a short distance and stopped in the gully bottom. Our thinking is that larger, more dangerous slabs could possibly still exist in very isolated, extreme terrain above treeline in narrow cross-loaded couloirs, rocky outcrops with leeward depressions, and steep leeward areas that are able to catch snow. So, yes they still could exist, but where most people are riding and sliding, concerns are minimal. The couple inches of new snow from last night will provide snow available for transport, but is not expected to create any problems. Normal caution is advised, so keep your eyes peeled for a rogue wind slab, and continue to use safe travel practices. LOW avalanche danger is not the green light for complacency. Unstable snow on isolated terrain features could still result in an avalanche that could injure, bury, or kill someone. 

Mt Shasta viewed from Ash Creek Butte, 12/26/15. Photo: N Meyers

________________________________________________________________________________________________________________________________________________________________________

The Sand Flat cross country ski trails are in great shape and ready for your cross country skis or snow shoes. These are backcountry trails 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. Thank you, and enjoy!

The Pilgrim Creek Snowmobile Park is open! Trails are being groomed currently. Head to our "Education" tab on our website and find the snowmobile section for trail information, grooming status and other sledder resources!

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