West Slopes South

The weather is again flipping back to cold and snowy with minimal accumulations expected across the zone. Paradise could again receive the bulk of precipitation resulting in the highest potential for dry avalanches. Elsewhere, generally safe avalanche conditions should persist unless temperatures warm and the snow starts to shed.

Talk about your dynamic springtime weather. One day we have a cold snow-producing storm (Wednesday-Thursday), the next day a warm and partly sunny day (Friday), and now we’re looking at another cold storm on our doorstep Friday night. Unfortunately for winter-lovers, neither of these storms have been big snow producers around the West South. Paradise appears to have led the charge with up to 5” of new snow from the first round of showers on Wednesday and Thursday, and should again record higher accumulations on Saturday. These modest snow totals and cooling temperatures have us anticipating generally safe avalanche conditions throughout the zone. That doesn’t mean that hazard doesn’t exist out there, particularly at Paradise where those slightly higher snow totals have been increasing incrementally.

Regardless of your location, if you find that the snow is cold and dry, be sure to look out for isolated pockets of wind-drifted snow to steer around at upper elevations. On shadier slopes on the northern end of the compass, Wednesday night’s snow may not have fully warmed up on Friday. In these areas, you could find more layered cold snow to consider for potential slab avalanches above the 3/30 crust. 

On the flip side, any existing cold dry snow, whether new or older, will be of concern for wet avalanches once temperatures warm or sunshine breaks through the clouds. This could be as early as Saturday afternoon or could wait until Sunday. On Friday, NPS rangers at Mount Rainier reported that their 5” of snow destabilized with warming temperatures and small wet loose avalanches were prone to human-triggering. If you notice the weather changing throughout the day on Saturday, take a look at the snow surface to see if it is heating up. It could start the day firm, but if it’s become wet and sticky or you see fresh rollerballs and pinwheels, be sure to start thinking about wet avalanches such as wet loose, cornice collapses, or glide. Springtime weather is dynamic and it often doesn’t take much to flip the snowpack from cold and dry to warm and wet. 

Additionally, this is the time of year the snowpack starts to shed its winter coat. Cornices that have built through multiple winter storms like to collapse and blocks of snow like to fall from rocky areas. These unpredictable shedding events can act as triggers on the slopes below, causing slabs to fail or larger debris piles. On Friday, one of these avalanches is suspected to have occurred on Mount St. Helens. In this particular event, a slab was released on the slopes below where the avalanche was initiated. On Saturday, we expect most avalanches, whether they are wet or dry, to be isolated to the snow above the 3/30 interface. But as the event on Mount St. Helens reminds us, a very large trigger from one of these shedding events could impact the snow below the 3/30 in isolated areas. This is further evidence that you should not linger under these ticking time bombs.