Last Known Eruption
39d 22h 47m ago

Latest Eruptions

Eruption DurationInterval
08 Apr 2022 @ 2117 wc2h 56m 9h 2m
08 Apr 2022 @ 1215 ie wc17h 3m
07 Apr 2022 @ 1912 ie wc6h 18m
07 Apr 2022 @ 1254 ie wc3d 20h 6m
03 Apr 2022 @ 1648 wc5h 32m
03 Apr 2022 @ 1116 ie wc19h 3m
02 Apr 2022 @ 1613 ie wc6h 18m
02 Apr 2022 @ 0955 ie13h 55m
01 Apr 2022 @ 2000 ie wc9h 32m
01 Apr 2022 @ 1028 ie wc17h 15m
31 Mar 2022 @ 1713 ie wc7h 58m
31 Mar 2022 @ 0915 ie wc16h 53m
30 Mar 2022 @ 1622 ie wc6h 2m
30 Mar 2022 @ 1020 ie wc2d 41m
28 Mar 2022 @ 0939 ns wc1d 1h 11m
27 Mar 2022 @ 0828 ie wc1d 58m
26 Mar 2022 @ 0730 ie wc22h 49m
25 Mar 2022 @ 0841 ie wc18h 32m
24 Mar 2022 @ 1409 ie wc21h 35m
23 Mar 2022 @ 1634 ie wc1d 7h 12m
22 Mar 2022 @ 0922 ie wc1d 19h 10m
20 Mar 2022 @ 1412 ie wc2d 2h 53m
18 Mar 2022 @ 1119 ie wc5d 1h 24m
13 Mar 2022 @ 0955 ie5d 19h 38m
07 Mar 2022 @ 1317 ie wc20h 15m
06 Mar 2022 @ 1702 ie wc7h 22m
06 Mar 2022 @ 0940 ie1d 6m
05 Mar 2022 @ 0934 ie23h 38m
04 Mar 2022 @ 0956 ie wc16h 2m
03 Mar 2022 @ 1754 ie wc8h 10m
03 Mar 2022 @ 0944 ie15h 33m
02 Mar 2022 @ 1811 ie wc1d 2h 27m
01 Mar 2022 @ 1544 ie wc8h 30m
01 Mar 2022 @ 0714 ie wc23h 24m
28 Feb 2022 @ 0750 ie wc1d 18h 46m
26 Feb 2022 @ 1304 ns wc1d 35m
25 Feb 2022 @ 1229 ie1d 10m
24 Feb 2022 @ 1219 ie wc18h 42m
23 Feb 2022 @ 1737 ie wc2d 7h 42m
21 Feb 2022 @ 0955 ie16h 33m
20 Feb 2022 @ 1722 ie wc1d 8h 9m
19 Feb 2022 @ 091323h 16m
18 Feb 2022 @ 09573d 19h 23m
14 Feb 2022 @ 1434 ie wc1d 29m
13 Feb 2022 @ 1405 ie23h 35m
12 Feb 2022 @ 1430 ie wc5h 30m
12 Feb 2022 @ 0900 ie2d 47m
10 Feb 2022 @ 0813 ns wc1d 20h 58m
08 Feb 2022 @ 11154h 15m
08 Feb 2022 @ 0700 ie wc21h 49m
07 Feb 2022 @ 0911 ie1d 18h 41m
05 Feb 2022 @ 1430 ie7h 14m
05 Feb 2022 @ 0716 ns wc20h 6m
04 Feb 2022 @ 11103h 25m
04 Feb 2022 @ 0745 ie19h 20m
03 Feb 2022 @ 1225 ie wc3d 19h 17m
30 Jan 2022 @ 1708 ie wc1d 8h 12m
29 Jan 2022 @ 0856 ie1d 21h 26m
27 Jan 2022 @ 1130 ie1d 20m
26 Jan 2022 @ 1110 wc1d 23h 54m
24 Jan 2022 @ 1116 ie1d 3m
23 Jan 2022 @ 111320h 34m
22 Jan 2022 @ 143922h 9m
21 Jan 2022 @ 1630 ie4h 45m
21 Jan 2022 @ 1145 ie21h 11m
20 Jan 2022 @ 1434 ie4h 59m
20 Jan 2022 @ 0935 ie2d 18h 9m
17 Jan 2022 @ 1526 ie5h 45m
17 Jan 2022 @ 0941 ie20h 30m
16 Jan 2022 @ 1311 ie3h 17m
16 Jan 2022 @ 09541d 3h 34m
15 Jan 2022 @ 0620 ie1d 16h 44m
13 Jan 2022 @ 1336 ie22h 0m
12 Jan 2022 @ 1536 ns7h 36m
12 Jan 2022 @ 0800 ie16h 0m
11 Jan 2022 @ 1600 ie2d 6h 20m
09 Jan 2022 @ 0940 ie1d 1h 58m
08 Jan 2022 @ 0742 ie wc3d 22h 7m
04 Jan 2022 @ 0935 ie20h 29m
03 Jan 2022 @ 1306 wc3d 3h 27m
31 Dec 2021 @ 0939 ie4d 1m
27 Dec 2021 @ 0938 ie wc4d 45m
23 Dec 2021 @ 0853 ie3d 1h 33m
20 Dec 2021 @ 0720 ie wc9h 37m
19 Dec 2021 @ 2143 wc8h 3m
19 Dec 2021 @ 1340 wc17h 19m
18 Dec 2021 @ 2021 wc3h 27m
18 Dec 2021 @ 1654 ie wc3d 7h 33m
15 Dec 2021 @ 0921 ie2d 51m
13 Dec 2021 @ 0830 ie wc1d 23h 54m
11 Dec 2021 @ 0836 ie wc3d 53m
08 Dec 2021 @ 0743 ie wc3d 15h 28m
04 Dec 2021 @ 1615 wc1d 9h 7m
03 Dec 2021 @ 0708 ie wc15h 16m
02 Dec 2021 @ 1552 ie wc2d 6h 58m
30 Nov 2021 @ 0854 ie wc23h 49m
29 Nov 2021 @ 0905 ie wc18h 39m
28 Nov 2021 @ 1426 ie wc1d 1h 58m
27 Nov 2021 @ 1228 ie wc4d 3h 45m
23 Nov 2021 @ 0843 ie wc22h 26m

Interval Statistics

Interval Count100
Min3h 17m
Max5d 19h 38m
Mean1d 8h 58m
Median23h 20m

Latest Notes

Note IDStart Time (US/Mountain)End Time (US/Mountain)EntrantNote
21018 17 May 2022 @ 2326 --- hkoenig {Still Quiet}
21017 17 May 2022 @ 2226 --- hkoenig {Still Quiet}
21016 17 May 2022 @ 2224 --- hkoenig {Still Quiet}
20717 17 Jan 2022 @ 1240 --- Graham Not ie at this time.
20648 08 Jan 2022 @ 0913 --- aferrara Off sometime before this time. probably within 20 minutes.
20127 25 Oct 2021 @ 1549 --- Darcie In eruption. Marathon pool is low (well below the orange ring)
20009 16 Oct 2021 @ 2220 --- Brando Still ie at 22:20
19919 06 Oct 2021 @ 1540 06 Oct 2021 @ 1615 aferrara Off sometime in this window
19851 02 Oct 2021 @ 1340 --- Kitt B Central ent delay at Grotto
19822 01 Oct 2021 @ 0755 --- ddshepard Grotto is off
19819 30 Sep 2021 @ 1950 --- Graham End. No Rocket.
19803 30 Sep 2021 @ 1427 --- ddshepard Grotto off about this time. No Rocket major observed from about 13:45 onward
19795 29 Sep 2021 @ 1758 --- Frypan9 Eruption stopped at 17:58
19765 28 Sep 2021 @ 0650 --- Graham Off when I walked by. Quit overnight after a 28+ hour eruption.
19753 27 Sep 2021 @ 1941 --- Graham Still ie from yesterday afternoon D>28h
19738 26 Sep 2021 @ 0912 --- User34 Off, was on just a few minutes prior
19729 25 Sep 2021 @ 1548 --- Graham Central vents on. Also 1556, 1606, 1738.
19725 25 Sep 2021 @ 0812 --- Brian Off now
19631 17 Sep 2021 @ 0943 --- CrisG eruption has ended
19571 14 Sep 2021 @ 2245 --- Brando Grotto appears to be off at this time
19500 12 Sep 2021 @ 0640 --- Graham Off and having an energy push. Bijou on, pressure pool up. Yesterdays eruption didn't go on too long, 6 to 10h, but maybe enough to get a Fountain today?
19501 11 Sep 2021 @ 2000 --- Graham Still ie.
19481 11 Sep 2021 @ 1733 --- User34 Two central vents on, Grotto shutting off, central vents cycled off and on and then Grotto restarted at 1739
19352 07 Sep 2021 @ 1040 --- Kitt B Grotto ended at 1040
19330 06 Sep 2021 @ 0916 --- Kitt B Grotto ended at 0916
19322 05 Sep 2021 @ 1924 --- Graham Quit 1924, so a short duration.
19315 05 Sep 2021 @ 1258 --- Graham Central vents ie. also 1337ie and 1347, 1m before Grotto started without Grotto Fountain.
19179 31 Aug 2021 @ 2135 --- William grotto on weak, marathon pool was low at this time.
19164 30 Aug 2021 @ 1251 --- Graham Ended 1251, duration just over 3h30m. One Rocket Major near the end.
19145 29 Aug 2021 @ 1144 --- BrianR End of eruption
19155 29 Aug 2021 @ 0728 29 Aug 2021 @ 0953 BrianR Very unusual activity in Grotto complex, one of the two strangest starts I have ever seen. At 7:28 I arrived at Grotto to here it grumbling without any water splashing. I then saw the “pressure pool” was up and heard water boiling at Grotto Fountain. I then saw that Spa was in overflow with fast moving water to the river. From past observations I knew this was going to cause chaos if Grotto is trying to start. Further observation of the fountain area I saw that besides Grotto Fountain boiling at about one feet, The two vents in front of South Grotto Fountain were also boiling. Now the details going forward: 7:28-8:28 Grotto - grumbling with No water splashes or central vent activity “Pressure Pool “ - always up Grotto Fountain - continuous 1 ft boil Two vents in front of South Grotto Fountain - 1 to 4 ft continuous boiling South Grotto Fountain main pool - barely a weak 1 ft splash every five minutes Startling - 1 to 2 ft sporadic splashing (I started to check it at 8:15) Spa - continuous strong overflow without any vents on 8:28 Spa - overflow stopped, pool starts to drop 8:28-8:59 All previous described activity continues except Spa is no longer in overflow 8:59 Grotto becomes silent, Grotto Fountain stops visible boiling 8:59 - 9:39 Grotto and Grotto Fountain - in conjunction, Three Grotto grumbling (still no water splashes) and Grotto Fountain boiling up to 4 ft episodes (9:06-9:09, 9:18-9:25, 9:33-9:39) with equal amount of time of silence and not boiling between. “Pressure Pool” - always up but changing level with Grotto Fountain South Grotto Fountain front vents - one or both now boiling a few inches to 2 ft, stronger when Grotto Fountain not boiling South Grotto Fountain main vent - still very little weak one ft splashes Startling - one ft sporadic splashes more. active when Grotto Fountain not boiling Spa - only half of its pool full at 9:30 9:42 Grotto Fountain starts a boil that leads to the 9:48 eruption, Grotto silent this time 9:52 South Grotto Fountain erupts 9:51 Grotto starts to grumble, has first splash of water at 9:52, and erupts at 9:53 A minute or so later Startling had a 4 ft burst followed by a couple of 2 ft bursts about a half minute later before South Grotto Fountain flooded it. It did not erupt. Note again this activity was already in progress upon my arrival
19642 28 Aug 2021 @ 0724 28 Aug 2021 @ 1808 BrianR Arrived at Grotto knowing that a marathon eruption ended sometime in the early morning Grotto Splashes of water: 12:36 18:08 Rocket Splashes of water: 8:09-8:10 8:36 9:36 11:23 12:00 12:24 14:19 14:59 First heard Grotto Fountain water: 15:05 Grotto Fountain splashes/boiling: 17:37 18:05-18:08 Pressure Pool up: 17:08 17:36-17:38 18:05-18:08 Spa pool level and vents: See 8/22 Spa comments for definition key 7:25 — 1, LV on (north pool vent) 9:01 — 1.25 9:34 — 1.5 9:45 — 1.75 10:40 — 2 10:48 — LV off 12:01 — 2 12:50 — 2.25 13:45 — 2.25 14:41 — 2.75 15:08 — 3 15:48 — 3 16:14 — 3.25 16:42 — 3.25 17:44 — 3.5 Left area at 18:15, heard next day that 2 more Pressure Pool up cycles were seen, but was left unattended after that.
19122 28 Aug 2021 @ 0615 --- William off when I passed at this time
19101 27 Aug 2021 @ 0825 --- BrianR End of eruption Expanded comments prior to end of eruption: Arrived at Grotto 7:16 to find it i.e. Grotto Central Vents: Upper Pair 8:08-8:14 Upper Pair 8:22-8:24 Spa pool level and vents: See 8/22 Spa comments for definition key 7:17 — 7, all vents off 7:30 — 5 7:39 — 3 8:16 — 1.25 8:41 — 2
19093 26 Aug 2021 @ 1803 --- BrianR End of eruption
19091 26 Aug 2021 @ 1415 --- BrianR End of eruption
19090 26 Aug 2021 @ 1117 --- BrianR End of eruption
19061 25 Aug 2021 @ 1447 --- BrianR End of eruption
19055 25 Aug 2021 @ 0823 --- BrianR End of eruption
19045 24 Aug 2021 @ 1403 --- BrianR End of eruption After eruption observations until I left area: Grotto Splashes of water: 16:56 Rocket Splashes of water: 16:32 First heard Grotto Fountain water boiling: 15:59 Grotto Fountain splashes/boiling: 15:59-16:05 16:13-16:34 16:48-16:57 Pressure Pool up: 16:52-16:57 Spa pool level and vents: See 8/22 Spa comments for definition key 14:05 — 2 14:41 — 3, LV on (north pool vent) 15:02 — 3.25 15:17 — 3.75 15:33 —- 4.1 15:47 —- 5 15:59 — 4.1, LV off 16:16 — 3.5 16:34 — 3.5 16:58 — 4 Left area 17:00
19044 24 Aug 2021 @ 0812 --- BrianR End of eruption Expanded comments: Arrived at 7:35 with Grotto i.e. “Rocket Little Buddies”: See 8/22 Grotto comments for definition key Main, Tiny, Key 7:35 i.e.-8:11
19029 23 Aug 2021 @ 0902 --- BrianR End of eruption Expanded comments relating to the previous Spa and Grotto eruption and the lead up to the next Grotto and Grotto Fountain eruption: Arrived at 7:33 to Grotto i.e. knowing Spa was seen in eruption at 6:20, but I did not see any bursts. Spa pool level and vents: See 8/22/21 Spa comments for definition key 7:34 — 9, LV, BRV, RV all on 7:45 — RV off (south pool forward vent) 7:51 — BRV off (south pool back vent) 7:52 — LV off (north pool vent) 8:08 — 4 8:27 — 1 8:32 — 0 9:08 — 1, LV on 10:06 — 1 10:31 — 1.5 11:03 — 1.5 11:31 — 2 12:13 — 2.5 12:46 — LV off 12:56 — 3 13:31 — 3.25 13:49 — 3.25 14:21 — 3 14:52 — 3.25 15:21 — 3.25 15:49 — 3.25 16:48 — 3.25 17:36 — 3.5 18:12 — 3.5 Grotto Central Vents: Upper Pair 8:59-9:02 Grotto Splashes of water: 10:59 “Rocket Little Buddies” See 8/22/21 Grotto comments for definition key Main & Tiny 8:10 i.e.-9:02 Key 8:58-9:02 Rocket Splashes of water: 9:43 9:46 10:15-10:17 10:27 10:59 11:24 11:28 12:03 12:41 13:15 13:39 Pressure Pool up: 16:02 16:44-16:46 17:30-17:34 18:18-18:23 Grotto Fountain splashes/boiling: 16:42 16:46 17:26 17:29-17:34 17:51 17:55 18:12 18:19-18:26 Unfortunately had to leave Grotto area at 18:30 did not get to see 19:13 Grotto Fountain eruption
18991 22 Aug 2021 @ 1520 --- BrianR End of eruption Expanded details before and after eruption ended follow 10:33 — arrived at Grotto i.e. “Rocket Little Buddies” definitions: Buddy layout north to south: Tiny, Main, Key (the hole) sit at the northwest corner of Rocket and Distant sits apart of the others at the middle (west) “Rocket Little Buddies”: Main & Tiny 10:33-15:20 Grotto Splashes of water: 17:23 Rocket Splashes of water: 15:40 15:58-16:00 16:16 16:18 16:55 17:24 Spa pool levels and vents: See Spa eruption comments for definition key and info before 15:20 15:31 — 0.5, LV on (north pool vent) 16:07 — 0.5 16:26 — 0.5 16:42 — 1 17:06 — 1.5 17:28 — 1.75 17:38 — 2, LV still on Left Grotto at 17:40
18868 08 Aug 2021 @ 2015 08 Aug 2021 @ 2035 William turned off during this time.
18751 31 Jul 2021 @ 1101 --- Dan A Grotto off
18727 29 Jul 2021 @ 1343 --- SantaFe108 Eruption ended. Rocket continued to splash till 1947.
18689 27 Jul 2021 @ 1540 --- JarnoO (wc) Marathon quit between 1533 and 1540, 19h15m < d < ~19h32m
18604 23 Jul 2021 @ 1331 --- BrianR End of eruption
18594 22 Jul 2021 @ 1158 --- BrianR End of eruption
18564 21 Jul 2021 @ 1605 --- BrianR End of marathon eruption
18558 21 Jul 2021 @ 0615 --- BrianR Eruption from 15:38 yesterday is still I.e
18553 20 Jul 2021 @ 1219 --- BrianR End of eruption
18552 20 Jul 2021 @ 0630 --- BrianR Grotto is off upon my arrival in area
18531 19 Jul 2021 @ 1729 --- BrianR End of eruption
18530 19 Jul 2021 @ 1355 --- BrianR End of eruption
18529 19 Jul 2021 @ 0813 --- BrianR End of eruption
18515 18 Jul 2021 @ 1944 --- BrianR End of eruption
18514 18 Jul 2021 @ 1458 --- BrianR End of eruption
18513 18 Jul 2021 @ 1108 --- BrianR End of eruption
18482 17 Jul 2021 @ 1755 --- BrianR End of eruption
18481 17 Jul 2021 @ 1129 --- BrianR End of eruption
18385 12 Jul 2021 @ 1254 --- deanl ending after 2 rockets!
18357 11 Jul 2021 @ 1126 --- William central vents delay, high water volume in grotto.
18337 10 Jul 2021 @ 0758 --- donnielg Off at 7:58
18318 09 Jul 2021 @ 1022 --- donnielg Off at 10:22
18285 06 Jul 2021 @ 0650 --- deanl was ie at 6:50 - don't know how long
18231 01 Jul 2021 @ 1909 --- William central vents delay
18229 01 Jul 2021 @ 1856 --- William central vents delay
18230 01 Jul 2021 @ 1830 --- William central vents delay around this time, did not get exact start of vents
18114 27 Jun 2021 @ 1509 --- TheHikingDude Off at this time. Deep gurgling.
18094 25 Jun 2021 @ 2222 --- annelies8 still ie
18075 24 Jun 2021 @ 2036 --- William grotto turned off at this time after Rocket maj
18029 22 Jun 2021 @ 1953 --- CrisG still ie
18010 22 Jun 2021 @ 1457 --- CrisG still IE. bijou slowing down
17979 21 Jun 2021 @ 1412 21 Jun 2021 @ 1416 William central vents active
17944 20 Jun 2021 @ 1801 --- K.Cooper off by this time
17903 19 Jun 2021 @ 0805 --- JimS Turned off by 0805 but still steaming and splashing.
17895 18 Jun 2021 @ 2208 --- CrisG still in eruption
17892 18 Jun 2021 @ 2036 --- Craigmon99 Still in eruption
17844 16 Jun 2021 @ 0713 --- CraigC Grotto shut off
17806 15 Jun 2021 @ 1323 --- CraigC Grotto shut off
17789 14 Jun 2021 @ 1947 --- Craigmon99 Off after rocket at this time
17787 14 Jun 2021 @ 1806 --- William steam in the area, near start... probably grotto?
17766 14 Jun 2021 @ 0905 --- CraigC Grotto shut off between 0845 and 0905
17756 13 Jun 2021 @ 2004 --- K.Cooper (wc) Grotto still ie at this time
17748 13 Jun 2021 @ 1614 --- CraigC Grotto shut off
17715 12 Jun 2021 @ 1443 --- CraigC grotto off
17696 12 Jun 2021 @ 1003 --- CraigC central vents splashing
17688 12 Jun 2021 @ 0722 --- CraigC Grotto shut off
17678 11 Jun 2021 @ 0843 --- TheHikingDude Grotto off, no sign of water on the entire platform. Calm as can be. Spa was 2 feet below the rim.
17654 11 Jun 2021 @ 0713 --- CraigC good energy cycle in Grotto, water barely visible in pressure pool at Grotto Ftn
17652 11 Jun 2021 @ 0638 --- CraigC marathon pool about 8 inches down
17590 08 Jun 2021 @ 1700 08 Jun 2021 @ 1835 annelies8 No eruption between these times that I saw, although from 1725 on I was dividing attention between this and Riverside. Not sure if it hasn't gone yet or I missed it earlier.
17541 07 Jun 2021 @ 2058 --- Craigmon99 still ie
17505 06 Jun 2021 @ 1128 06 Jun 2021 @ 1210 Polly Grotto marathon end sometime between 1128 and 1210.
17498 06 Jun 2021 @ 0630 --- CraigC Grotto ie., Marathon Pool appears about 4 inches below high water mark
17470 05 Jun 2021 @ 0850 --- CraigC Grotto off, observed from F&M
17243 29 May 2021 @ 0000 --- JarnoO (wc) Marathon continued overnight; Overnight captures: 0025, 0100, 0157, 0256. May have quit somewhere between 0256 and 0615. At first glance only passive steam rising at the latter time.
17232 28 May 2021 @ 1940 --- Ben VL Still IE when I left for Grand at this time.
17228 28 May 2021 @ 1300 --- JarnoO (wc) Marathon. Still ie 1300 (as well as seen ie somewhere around 1145), 1420, 1500, 1600, 1725, 1809, 1856, 1950. Daytime & overnight captures: 2100, 2200, 2300.
EntrySourceLinkComment
18 Aug 2020 @ 1452 JSJ https://www.youtube.com/watch?v=L4pz9gWnQwk Video by Craig Corless showing the start of Grotto Geyser's 2:52 PM-onward eruption on 18 August 2020, with both Grotto Fountain Geyser & South Grotto Fountain Geyser erupting in the background.
03 Oct 2019 @ 1526 EricZ https://www.youtube.com/watch?v=YpsAVShVyxs&feature=youtu.be Grotto Start
15 Aug 2018 @ 0941 JSJ https://www.flickr.com/photos/jsjgeology/32563168958 Photo of initial runoff (approaching Variable Spring) from Grotto Geyser's 9:41 AM-onward eruption on 15 August 2018.
15 Aug 2018 @ 0941 JSJ https://www.flickr.com/photos/jsjgeology/44618689690 Photo of Grotto Geyser's 9:41 AM-onward eruption on 15 August 2018.
14 Aug 2015 @ 1314 JSJ https://www.flickr.com/photos/jsjgeology/21145226344 Photo of Grotto Geyser's 1:14 PM-onward eruption on 14 August 2015.
08 Jul 2014 @ 1430 JSJ https://www.flickr.com/photos/jsjgeology/15106150617 Photo of Grotto Geyser erupting during the mid-afternoon of 8 July 2014.
Baseline does not exist.