Natural Avalanche Activity

Location Name: 
Naturals at All Elevations
Region: 
Williams Lake Area
Date and time of observation: 
Fri, 01/17/2020 - 14:26


Red Flags: 
Recent avalanche activity
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain

Observation made by: Professional Observer
Snowpit Observations
More detailed information about the snowpack: 

We have had 10-15" of snow with 1.2 to 1.5" of water since Thursday afternoon. This warm storm deposited snow in an upside down manner, with dense heavier snow overlying the lighter snow that fell Thursday. Snow continued throughout our tour. Strong winds and gusts in the mid-60's created a cohesive slab on the snow surface in open areas at all elevations. Due to these strong winds, the new storm snows depths were variable. We found areas where it was roughly a foot deep. In terrain features where winds transported this new snow, we found it as deep as four feet. Winds were strong enough to knock a person off their feet. 

We triggered a slide from a ridgeline. The snowpack was hair-trigger around mid morning, and fractured above us. It propagated widely, around 300 feet. This was consistent with reports we were getting from avalanche control teams. It was the only steep slope we approached during the day. We had reports of natural avalanches starting early morning below treeline, all the way to above treeline. They showed signs of stepping down into the persistent weak layers deeper in the snowpack and running long distances. Winds transported snow so rapidly that these avalanches were quickly hidden underneath the new snow. Whumfing and shooting cracks were constant at all elevations as we traveled. 

Photo 1: Constant strong winds with gusts in the 60's

Photo 2: We triggered this from the ridgeline

Photo 3: Shooting cracks within the new storm snow

Snowpack photos: 
Weather Observations
Blowing Snow: 
Yes
Cloud Cover: 
100% of the sky covered by clouds
Air temperature: 
Below Freezing
Wind Speed: 
Strong
Precipitation: 
Snow
Air temperature trend: 
Cooling
Wind Direction: 
Southwest
Accumulation rate: 
Less than 1 in. per hour
More detailed information about the weather: 

Temps in the low 20's dropped throughout the day. Snow continued to fall during the entirety of our tour. It was difficult to tell how much snow was actually accumulating due to the strong winds. These strong winds came from the southwest, with gusts in the mid 60's were constant at all elevations.