Turnagain Pass Avalanche Forecast

With just a few short breaks in weather over the last 9 days, we appear to be on the verge of a pattern change as it looks like we’ll be under at least a couple of days of high pressure starting this afternoon.  Storm snow issues listed below are of concern today and may prove more reactive if we get a spike in ambient temperatures, or a period of unobstructed sunshine.

Storm slabs:  Yesterday we found reactive storm slabs at 2500’ in our snow pit that consistently failed and propagated about 2 feet below the surface.  Granted, this is only one data point, but it happens to be on arguably the most heavily traveled piece of terrain in the Turnagain zone (Seattle ridge uptrack).  This may have been the same weak layer responsible for a Sunday afternoon natural storm slab on Tincan.  More data will help us understand if this weakness is widespread, but for today, keeping slope angles mellow and picking very conservative travel routes will be key.

Pit results yesterday identified a concerning mid-storm crust at 2500′ on Seattle ridge that proved reactive.  See video here.

Wind slabs:  There is ample snow available in the alpine for transport.  Winds have been primarily from the E and NE over the last several days loading any slope with a westerly tilt.  Last night, winds kicked back up into the 40’s, gusting to 70mph on Sunburst.  As with their cornice brethren, wind slabs have the potential to be large and dangerous today.  Avoid steep, wind loaded slopes and recognize that any direct sun today could act to weaken these wind slabs.

Cornices: These continue to grow large and unruly with the addition of more wind and snow.  Give cornices a wide berth if travelling on or below a corniced ridge.  Any significant cornice fall today is likely to trigger an avalanche on the slope below.

The wild card…. Glide cracks have continued to release during this storm cycle, still with no real discernable pattern.  Many cracks continue to litter the slopes above well-travelled terrain on both the motorized and non-motorized side of the highway.  Simply avoid exposure time spent below existing cracks to minimize your risk.  The photo below is a good reminder that if a skier or snowmachiner were to tangle with one of these full-depth glide avalanches, odds of survival are slim to none.

Snowmachine for scale next to the toe of a glide avalanche.  This released Thursday night/ Friday morning on the East face of Seattle ridge depositing 15-20′ of debris on a well-traveled snowmachine route.