Avalanche: Mt. Magog, South Face

Observer Name
Eric and Amy Flygare
Observation Date
Thursday, February 2, 2023
Avalanche Date
Sunday, January 29, 2023
Region
Logan » Logan River » Tony Grove » Mt. Magog » Mt. Magog, South Face
Location Name or Route
Mt Magog, South Slope
Elevation
9,600'
Aspect
South
Slope Angle
40°
Trigger
Natural
Avalanche Type
Hard Slab
Avalanche Problem
Wind Drifted Snow
Depth
2'
Width
150'
Vertical
600'
Comments
We were riding in the Tony Grove are and noticed a fair amount of avalanche activity. Most of the activity appeared to be several days old. There was an avalanche off of the south slope of Magog that looked interesting so we got closer to investigate. The avalanche started right under the cliffs at the top of Mt Magog on the South slope (see pic 1). The crown appeared to be 1 to 3 feet deep and 150 feet wide. What was interesting was how far the avalanche ran, all the way across the flats and started up the other side of the bowl about 450 feet away. The alpha angle of the slide was measured at about 22 or 23 degrees. The debris pile had some tree branches and was 3-5 feet deep across the valley floor. We dug a pit to the side of the old avalanche path to see how things looked and the avalanche tests were pretty non-reactive. We got a non-propagating failure at 25 taps about 2 feet down and that was it. The total snow depth in that location was 8.5 feet deep The weak layer that was responsible for the avalanche had strengthened (or did not exist in the pit location...)
Other than the several day old naturals avalanches, we were not able to get anything to slide today. There was plenty of wind loading from this week and we found significant sastrugi along all the ridge lines (see pic 2). Riding was not stellar at upper elevations due to all the wind affected zones. Even where the snow looked good, there were stout wind drifts in unexpected locations. We rode east, south, and west facing slopes and actually found the best riding on south facing slopes.
On the way out we started seeing wet sluffs on south facing slopes with some roller balls (see pic 3)
We also noticed two very large avalanches up Wood Camp on Ham Hill (south facing slopes at 7000 and 8400 feet. We could not get pictures of these slides but they would be very interesting to get a closer look at.
Coordinates