Turns out it was a mistake. Spent a whole night, and the next day, seeing weak hot periods and short Grotto eruptions. Grotto finally went into a marathon at 14:35, and Giant had the big hot period we'd been expecting for 36 hours shortly after that. The first six minutes of it seemed fairly ordinary, the only distinguishing feature being a number of previously quiet vents were active. Then, several minutes after Feather had quit, it restarted and Giant started massive surging. So much so that observers there insisted Giant was about to start. Unfortunately, it didn't, and now we wait out the marathon.
Grand seems to like having short intervals during the evening, night and early mornings, reserving the longer intervals for mid day when the crowds are the largest. The morning eruption was right at the time when the sun was appearing over the trees, so that only the tops of the jets, and the mass of the second burst were illuminated.
Other Geyser Times
- Grotto 00:42 d≈2h15m, 09:00 d≈1h15m, 14:39
- Grotto Fountain 08:57, 14:35
- Giant hot periods
- 00:16 d=4m37s
- 01:17 d=2m08s
- 02:27 d=4m32s
- 03:58 bathtub
- 05:02 bathtub
- 06:08 bathtub
- 07:15 bathtub
- 08:10 bathtub
- 09:05
- 10:04
- 10:56 bathtub
- 11:57 4m53s
- 12:51 bathtub
- 14:02 d=1m55s
- 15:11
- 15:57 d=2m22s
- 17:02 bathtub
- 18:02 d=5m55s + restart