| Date: | 2021-09-13 |
| Time: | 0612 |
| Geyser: | Grotto |
| Webcam: | Yes |
| Initial: | No |
| Major/Minor: | N/A |
| Duration: | >16h |
| Standardized Duration: | > |
| Time Entered: | 2021-09-14 08:52:10 |
| Time Updated: | 2021-09-14 15:31:43 |
| Time Uploaded: | 2021-09-14 15:31:43 |
| Entrant: | JarnoO |
| Observer: | GOSA Overnight Captures |
| Submitted to: | Geysertimes.org |
| Comments: | by plume peeking above fog; marathon - continued well into the evening and possibly night |