When I arrived, I found that the PW5 glider was not exactly where I left it, though I was pretty sure no one else had been flying it. The knots in the tie-down ropes were not mine, and it was about two feet further east. Hmm... Then I found that on the nose tie-down, the knot on the ring had come loose, which allowed the glider to yaw with the wind. Tracks under the wheels showed that it had "walked" the two feet, including dragging the main wheel over a sizable rock. The wing tie-down ropes had been on the ground cable, and had slid along it. Some good Samaritan had later moved the wing ropes to staked or concreted chains, which stopped it from walking any further. Mystery solved!
I only had to wait a short time for a tow. As soon as I lifted off, the tail yawed about 15-20 degrees to the right, and the glider drifted over the right edge of the runway. No amount of rudder would counteract it. (The PW5's rudder is really tiny.) As the chief instructor later noted, it was the kind of thing which would cause a new pilot to release and land straight ahead on the runway, which I did consider, but as it was not getting any worse, I decided to stick it out. As we gained airspeed, I gained more rudder authority, and all was well.
Since the best lift was reported to be over the mountains, and I kind of got skunked last time, I took a high tow and let off in good lift. It was all uphill from there.
I spent most of the next two hours between 8,000 and 10,000 feet under and between these nice cumulus clouds. Figuring out which ones were building and which were dissipating was the biggest challenge of the day. Great fun!
There was indeed a strong north wind at altitude, and if I did not pay attention to it while thermalling it kept drifting me south toward the mountains. Outside air temperature was about 0 to -2 Celsius, but only my feet got cold, and only after about 90 minutes.
Approach and landing were... interesting. The ground reported the wind as being from the northeast. When I got low enough to see the tetrahedron, it indicated wind from the northwest. I decided it was not strong enough to change landing directions from runway 25 to runway 7. Then on final approach, my airspeed increased quite a bit, so it seems that the wind had diminished, leaving me with a lot of kinetic energy. That energy turned into quite a long float before touchdown (which was not at a high ground speed, so it's not like I had a tailwind). By the time I stopped rolling, the wind socks were all straight down - dead calm! So it seems that I had the bad timing to approach and land as a thermal passed through, which caused complete rotation of the wind direction over the course of a few minutes.
All in all, a fun two-hour flight with challenges at both ends.