Powderhouse Peak

Location Name: 
Powderhouse
Region: 
Luther Pass Area (including Job and Freel)
Date and time of observation: 
Tue, 01/19/2016 - 12:00
Location Map: 
United States
38° 47' 11.9004" N, 119° 58' 32.2212" W
See map: Google Maps
US


Red Flags: 
Whumphing noises, shooting cracks, or collapsing
Recent loading by new snow, wind, or rain
Terrain Trap
Observation made by: Professional Observer
Snowpit Observations
More detailed information about the snowpack: 

Wind and storm slab conditions were widely observed at Powderhouse today. Cracking around skis while skinning was common on the upper half of the mountain especially closer to ridges and the summit. Storm slab instabilities were observed in the trees away from ridges, likely resulting from temperature spikes during the storm. Skiers and snowboarders commented that the snow rode a bit upside down, with heavier and denser snow on the surface. 

A rider triggered a small slab on a steeper rollover mid-mountain and away from ridges or the peak. This was small and inconsequential in this location but  clearly an indicator that instabilities exist within the new snow and consequences could be higher on steeper and more wind affected terrain. At the crown's highest point it was about 6 inches tall. 

Photo 1: Small storm slab in the trees at Powderhouse. Slab ran the length of the steeper rollover (approximately 30 feet). 

Photo 2: Flank area of storm slab showing the slab properties of the surface snow. The heavier snow closer to the surface was only marginally more cohesive than the lighter snow below but that was enough. This cracking was relatively far (approximate 20 feet) from the steepest section of the rollover, and from the original trigger point, and from the path of the rider.

Photo 3: One of the largest tree bombs I've observed. This fell on the edge of the skin track between laps. The skin track is also visible in the photo and shows that it was largely covered by falling and blowing snow since the last skinner passed through this area (estimated at less than an hour).

Photo 4: The main block of snow that fell off the tree w/ the pole for scale. Especially interesting is the blast radius around the block of snow. A smaller (but still heavy enough to cause damage block) sat directly on the skin track. 

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

Strong winds that, at least at this location, were swirling and transporting snow in a variety of directions. At several points north to northwest winds were observed blowing snow. Temperature appeared to rise slightly throughout the day. Snow levels hovered a bit above the 7700 elevation at Luther Pass in the morning and climbed a couple hundred feet higher by midday.