Last night it was extremely windy, with large gusts barreling down the river valley. The forecast was for 2-6″ of snow, but we ended up with only a dusting as the nor’easter storm held mostly to the south. Our solar tracker, however, decided it was better to spend the gusty night horizontally.
The panel has an anemometer on the upper-right corner – seen here in the right-most corner, on a gimbal so it stays upright regardless of the panels’ angle – and when it detects high winds or strong gusts, moves the panels into a horizontal position to protect itself. It spent the night this way.
Normally, it spends the night in a vertical position, to avoid accumulating snow, ice, or dust. This morning, the winds are calm; when the sun rose , though invisible behind the clouds, the tracker steered into its normal sun-tracking mode.