Observation: Mill D North

Observation Date
3/15/2018
Observer Name
Nathan Chaszeyka
Region
Salt Lake » Big Cottonwood Canyon » Mill D North
Location Name or Route
Mill D North
Weather
Sky
Obscured
Precipitation
Light Snowfall
Weather Comments
Very low visibility and flat light. Snow was intermittent with light to moderate rates. Temps in the 20's felt very warm even though much cooler than earlier in the week.
Snow Characteristics
New Snow Depth
4"
New Snow Density
Medium
Snow Surface Conditions
Powder
Snow Characteristics Comments

Little new snow on top of a very damp old surface snow made for "punchy" skiing at times. If you were light on your feet it skied well, but heavy use of the edges was inadvisable. A healthy mix of thick graupel was easily visible in the new snow. I tried to get a photo but could not get the camera lens to defog enough for a clear photo.

Red Flags
Red Flags
Cracking
Collapsing
Poor Snowpack Structure
Red Flags Comments
Skinning over the top of the Cone generated some localized cracking and collapsing. The water percolating down through the old snow has ripened the thicker facet layers into readily collapsing in certain areas. Some wind loading was noted but difficult to distinguish how recent in the low and flat light. I did not find any pockets of this wind loading that showed signs of being reactive, so I suspect that they are older.
Avalanche Problem #1
Problem
Persistent Weak Layer
Trend
Increasing Danger
Problem #1 Comments

Underneath the new snow is at least 18" of heavily saturated old snow. Probing with pole plants indicated very weak snow below that. Given the cracking and collapsing that I found, I believe that in steeper areas could be rather easy to trigger a deep slab avalanche right now. This storm continuing at times through the day and forecast to pick up again on Saturday has me feeling that the danger of this problem will rise as more water weight is added.

Avalanche Problem #2
Problem
Wet Snow
Trend
Same
Problem #2 Comments

Really similar, and rather related to the Deep Slab problem is a Wet Slab concern. This storm has been very wet and the layers below the new surface snow appear to be well saturated.

Today's Observed Danger Rating
Considerable
Tomorrows Estimated Danger Rating
Considerable