Silver Star Post Frontal Sunday

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Michael Coppock

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Sep 13, 2021, 10:42:12 PM9/13/21

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The memories of my previous White Room incident on Silver Star complicated my flight decisions immediately after launching. The flight plan had been to push NW in to expected 10kt + NW flow to avoid being beamed up in to the tendrils of condensation hanging from the dark Cloudbase perched over launch. However, the widespread lift encountered near Squaw Butte was unexpected. Full bar in to the NW flow lead to >2 m/s up in smooth magic air. No turbulence at all. Big Ears and speed bar were unlikely to be useful given need to push NW into strong flow. Spirals would be problematic given proximity to ground, and potential for cloud base to drop, as it had intermittently during the ½ prep for launch. Cloudbase was dark, and extensive in area.

So, how had the day progressed?

12:45 Departing my house in La Center at 700’ MSL, winds were strong out of the NW.
Driving past Moulton Falls, meteo winds were keeping the trees active, an unusual site to have wind.
At Tarbell trailhead N, 10kt winds from NW moaned in the trees.
1:30 Cloudbase was down to west upper parking lot, as viewed from L1100 road.
At 1900’ LZ, it was calm, and a Turkey Vulture struggled to find lift.
2:00 Light rain showers to west and on Silver Star started on time, as predicted by Windy and MB
2:30 Cloud base continued to slowly rise on the hike up. Two consecutive eagles spun in wide circles, ascending at impressive rates, and disappeared in to the ratty condensation layers.
3:30 Sturgeon Rock intermittently showed, wrapped in torn cloud…?thermic flow or meteo wind?
4:00 Cloud base rising as predicted by SkySight, MB, and NAM12, clearing to the east, with Cloudbase around 5k.
4:30 Two Eagles over Squaw Butte did aerial tango, merging and separating in a splendid dance, and then sped N at Cloudbase…time to launch!
5:00 Launched in to moderate thermal activity, and headed N and west in predicted NW flow as above. Pushing to west, the lift lessened a little, so I turned back in to the Squaw Butte area where the eagles had spun up to Cloudbase, there lift was impressive, I suspect a combination of ridge lift as indicated by SkySight, the good lapse rate, possible thermal lift, and minor cloud suck. SkySight had also indicated a band of convergence draped from SW to NE over the area at 0.25 m/s at the boundary layer above me. Cloudbase was difficult for me to assess, but likely around 4500’ initially, so 400-500’ above. The >2 m/s absolutely smooth ascendance on full bar continued until I dropped below 3800’. Light thermals persisted below this layer. I think a pilot experienced with cloud flying would have been in solid lift, staying above 4,000’ heading N. Cloud street-like appearing conditions persisted until dusk. As predicted, Cloudbase rose steadily to 7-8 k by 7 pm.

Given the late hour, the cold, the perceived risk of ending up in the cloud disoriented, and blowing back to the east in the strong NW flow: I opted for an extended sledder, and landed in calm conditions in the lower LZ.

The golden sunlight filtering through to illuminate green forests and hills, the scudding cloud, and the clarity of the air continued until dusk.

Lessons learned:

1.White room experiences are powerful negative reinforcement to avoid repeat episodes.
2.Magic air can occur at times other than glass off it appears. MB predicted little to zero wind shear, at launch altitude.
3.Post frontal conditions, even weak ones like the decaying system on Sunday provide amazing air, and opportunities to fly out of the Silver Star area.
4.Ridge lift, indicated on SkySight, from the Tarbell ridge, and Kloochman Butte area; must be a part of the reason launch is protected from NW flow. And this fits with the lack of protection from east flows.
5.There is a huge volume of air moving from the Columbia river geographic funnel in NW conditions that is pointed directly at Silver Star launch, but deflected higher, or around it in some way.
6.The accuracy of Windy, Meteoblue, NAM-12,and SkySight for the condensation layer elevation during the afternoon, the changes in high, mid, and low cloud, and the precipitation predictions were astounding, and reassuring.