Tumalo tour conditions

Red Flags:
Recent avalanche activity

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Updated:
Friday, Mar 10, 2017 6:51 PM
Observer(s):
Aaron Hartz
Position:
Pro Ob
Location:
Three Sisters Area (44.005086, -121.641312)
Ob Date/Time:
Fri, Mar 10, 2017 - 6:46 PM
Report Type:
Snow Conditions
Mode of Travel:
Ski or Snowboard

Written Report:
As I pulled up to Dutchman Flat parking lot and saw the river of water running across the pavement, I was expecting wet and mushy snow. I was glad to find the snow surface was supportable and not mushy at all. The air temperature this morning near the parking lot was just below freezing and the sky was partly sunny. Almost everywhere, the snow surface was covered in runnels, where the water was channeling on the surface during the previous day's rain event. The wind was light our of the WSW. On the summit, the wind picked up a little and was light with moderate gusts out of the west. There was widespread cornice debris throughout the bowl. The warming and rain from yesterday, really did a number on the cornices. Some chunks were as big as refrigerators and traveled the entire way down the bowl. In a few places at the top of the bowl, the cornices are almost 20 tall. Also, for the the third time this season, I saw slab avalanche debris going the distance to the bottom of the bowl. This slab appeared to be triggered by a cornice failure. The slab was most likely a combination of wind/storm/wet slab. The crown was about 50m(160ft) wide at the top and about 20-30cm thick. The debris pile at the bottom was definitely big enough to bury a person. I am guessing this slide happened sometime within the last 24 hours. The debris looked fresh
The rain caused the upper snow pack to become upside down (denser snow on top and less dense/softer snow below) in the upper 30cm(12"). This can be considered a weakness in the snow pack, but will most likely only come into play in steep (upper 30 degree) terrain and/or unsupported terrain. There were also two layers down 20 and 24cm that were saturated with water. I could squeeze water out of the snow in these layers. One of these could have been the 'wet slab' weak layer from yesterday.


It felt like a spring day. Ski quality was good on E, W, and Southerly aspects.



More snow and weather information:
Time: 10:40 Elevation: 6450 0ft Location: West side of Tumalo
Aspect: WSW Sky: Broken Clouds
Precip: No Air Temp: -1C (30F)
Wind: Calm/Light WSW
Height of snow: 300cm(118")
Ski Pen: 1-4cm


Time: 12:15 Elevation: 7700 0ft Location: Tumalo summit
Sky: Scattered Clouds
Precip: No Air Temp: -4.5C (24F)
Wind: Light (moderate gusts) WSW

Time: 13:00 Elevation: 7200ft Location: Bottom of Tumalo bowl
Aspect: ENE
CTH down 20cm RP on a layer of water saturated snow
CTH down 24cm RP on a layer of water saturated snow




Multimedia

Caption: Slab crown at the top of the bowl

Caption: Looking down at the slide path and debris

Caption: Debris pile at the bottom of the bowl

Caption: Large cornices