Observation

From: K Dumain
Activity_Date: 1/1//01
Remote Name: 172.170.184.156

Comments

I saw the entire event as well and having read the other accounts I'll be brief and just add a few additional comments.

There was evidence prior to SD launching of stronger NE winds than he reported. Debbie had been reporting peak winds into the teens that morning. Factoring in the probability of reduced readings on the ground due to surface friction or mechanical turbulence, and the cloud formations present out front, it was apparent that the NE winds aloft were significantly greater than 5-8. In retrospect, the winds may have been building based on the mid day clouds and lack of the usual southside thermal block.

Tom's flight was beautiful, until he got back to Tunnel Tit.

His experience reminds me of an article in Sailing World, and my personal experience sailing at Huntington Lake in the Sierra. Wind on the lee side of a major ridge (Camino Cielo) will tend to behave in a vertically oscillating or roller coaster manner. At Huntington, the wind comes up the canyon and climbs over the dam. Behind the dam on the lake there is almost no wind. The wind has been deflected overhead. Farther down the lake, the wind begins to hit the surface in sporadic puffs. These puffs are traces of the wind at the low points of the roller coaster cycle. Farther down the lake the roller coaster cycle dissipates and the wind maintains regular contact with the surface at an increased velocity.

I suspect that SD hit a low gust, which was further disturbed by the immediate geography of the upper Holy Hills. The large expanse of upper Rattlesnake Canyon makes it possible for the NE to cycle to lower elevations where he got whacked.

The moral, wind on the lee side is not prone to continuous predictable behaviour.