Last Known Eruption
38d 11h 54m ago

Latest Eruptions

Eruption DurationInterval
14 Jan 2024 @ 161048d 3h 34m
27 Nov 2023 @ 12361d 21h 16m
25 Nov 2023 @ 1520 wc1d 1h 11m
24 Nov 2023 @ 1409 ie wc39d 21h 20m
15 Oct 2023 @ 17495h 40m
15 Oct 2023 @ 1209 ie16d 17h 32m
28 Sep 2023 @ 18379m 7h 35m
28 Sep 2023 @ 110216m 7d 19h 6m
20 Sep 2023 @ 155621m 5h 43m
20 Sep 2023 @ 101326m 10d 17h 18m
09 Sep 2023 @ 16556m 3d 1h 47m
06 Sep 2023 @ 150813m 6h 40m
06 Sep 2023 @ 082812m 14h 52m
05 Sep 2023 @ 173625m 2d 7h 0m
03 Sep 2023 @ 103610m 2d 2h 7m
01 Sep 2023 @ 08293m 2d 16h 25m
29 Aug 2023 @ 16041d 3h 36m
28 Aug 2023 @ 12283d 18h 9m
24 Aug 2023 @ 18194m 3d 9h 5m
21 Aug 2023 @ 09142.5m 20h 18m
20 Aug 2023 @ 12565.5m 21h 18m
19 Aug 2023 @ 153827m 10d 6h 49m
09 Aug 2023 @ 0849 ns1d 20h 51m
07 Aug 2023 @ 11588m 57s 22h 18m
06 Aug 2023 @ 1340 ie23h 31m
05 Aug 2023 @ 140924m 5h 0m
05 Aug 2023 @ 0909 ie5d 12h 18m
30 Jul 2023 @ 2051 ns~12m 3d 8h 29m
27 Jul 2023 @ 12228m 30s 16h 47m
26 Jul 2023 @ 1935 ie1d 4h 34m
25 Jul 2023 @ 1501 ns5h 24m
25 Jul 2023 @ 093729m 7d 14h 31m
17 Jul 2023 @ 1906 ie2d 2h 6m
15 Jul 2023 @ 17008m 2d 5h 18m
13 Jul 2023 @ 1142 ie16h 7m
12 Jul 2023 @ 1935 ns29m 1d 6h 38m
11 Jul 2023 @ 125711m 21h 51m
10 Jul 2023 @ 1506 ns18h 17m
09 Jul 2023 @ 204912m 53s 4h 12m
09 Jul 2023 @ 163723m 4d 5h 6m
05 Jul 2023 @ 11318m 2d 20h 8m
02 Jul 2023 @ 15232d 2h 36m
30 Jun 2023 @ 12476m 23h 28m
29 Jun 2023 @ 13196m 20h 23m
28 Jun 2023 @ 165613.5m 8h 5m
28 Jun 2023 @ 085112m 8d 16h 26m
19 Jun 2023 @ 1625~27m 2d 1h 29m
17 Jun 2023 @ 14561d 7h 11m
16 Jun 2023 @ 0745 ie14h 48m
15 Jun 2023 @ 165716m 5h 39m
15 Jun 2023 @ 111827m 4d 22h 39m
10 Jun 2023 @ 123922h 43m
09 Jun 2023 @ 1356 ie3d 3h 48m
06 Jun 2023 @ 10082d 23h 8m
03 Jun 2023 @ 1100 ie2d 22h 43m
31 May 2023 @ 12171-2 m1d 18h 24m
29 May 2023 @ 17531d 3h 52m
28 May 2023 @ 14016h 44m
28 May 2023 @ 07174d 12h 56m
23 May 2023 @ 18217h 28m
23 May 2023 @ 10532d 20h 42m
20 May 2023 @ 141118h 49m
19 May 2023 @ 192214m 7h 56m
19 May 2023 @ 112628m 5d 23h 19m
13 May 2023 @ 1207 ie2d 21h 26m
10 May 2023 @ 1441 ie15d 7h 23m
25 Apr 2023 @ 0718 ie1d 21h 49m
23 Apr 2023 @ 09292d 18h 28m
20 Apr 2023 @ 1501 ie60d 4h 51m
19 Feb 2023 @ 0910 ie36d 18h 12m
13 Jan 2023 @ 145810m 5h 44m
13 Jan 2023 @ 0914~11m 70d 20h 55m
03 Nov 2022 @ 1319 ie5d 22h 12m
28 Oct 2022 @ 1507 ie12d 22h 54m
15 Oct 2022 @ 161319m 16d 2h 41m
29 Sep 2022 @ 13326d 20h 50m
22 Sep 2022 @ 16426m 2d 12m
20 Sep 2022 @ 163012m 6h 5m
20 Sep 2022 @ 102516m 4d 17h 50m
15 Sep 2022 @ 163512m 7h 29m
15 Sep 2022 @ 090612m 2d 21h 51m
12 Sep 2022 @ 1115 A6d 3h 31m
06 Sep 2022 @ 0744 ns2d 13h 3m
03 Sep 2022 @ 18415m 3d 8h 0m
31 Aug 2022 @ 104117h 19m
30 Aug 2022 @ 1722 ie wc6h 20m
30 Aug 2022 @ 11021d 19m
29 Aug 2022 @ 104322m 2d 20h 51m
26 Aug 2022 @ 13524m 1d 1h 9m
25 Aug 2022 @ 12432m 20h 21m
24 Aug 2022 @ 162213.5m 6h 19m
24 Aug 2022 @ 100315.5m 2d 1h 23m
22 Aug 2022 @ 084011m 15h 25m
21 Aug 2022 @ 171515m 7h 37m
21 Aug 2022 @ 093817.5m 4d 20h 8m
16 Aug 2022 @ 1330 ie2d 47m
14 Aug 2022 @ 124327m 9d 6m
05 Aug 2022 @ 12379m 7d 0m
29 Jul 2022 @ 123710m 1d 4h 3m
28 Jul 2022 @ 0834 ie3d 14h 36m

Interval Statistics

Interval Count100
Min4h 12m
Max70d 20h 55m
Mean5d 9h 21m
Median2d 1h 5m

Latest Notes

Note IDStart Time (US/Mountain)End Time (US/Mountain)EntrantNote
28813 15 Oct 2023 @ 1158 --- Ben VL Pressure pool up & drop.
27023 12 Jul 2023 @ 1836 --- Ben VL Pressure pool up and dropped. Not sure how many there have been.
26342 15 Jun 2023 @ 1405 --- Graham 1405 Small boil. Pressure Pool low. Also 1434, 1446, break, 1528 high water, good boil, 1546 weak, 1609 strong, almost started, 1643 weak, 1656
25583 20 May 2023 @ 1305 --- Brando boiling ~8 inches
24286 06 Oct 2022 @ 1227 --- DanS In overflow
23474 29 Aug 2022 @ 0959 --- Art Started erupting 3-4’ then stopped after 3 minutes.
21722 04 Jun 2022 @ 1346 --- Graham Pressure Pool up and small boil. Again 1403, 1414, 1427, 1439, 1447 and GF boiling steadily. 1451 rise and boil continues. 1457 GF erupted. 10m of boiling before it committed to an eruption.
21551 28 May 2022 @ 1149 --- Graham Pressure pool up but not full. No boiling in GF. Also 1204, 1211. 1223 up and full. Also 1235, 1250, 1304, 1315, 1326, 1338. 1340 small boil d=3m.
19826 01 Oct 2021 @ 1317 --- SteveO Grotto Fountain bubbling a little bit, 1 st visible in the Pressure Pool.
19770 28 Sep 2021 @ 1513 --- Kitt B Pressure pool is up and dropped at 1515.
19508 12 Sep 2021 @ 1108 --- Graham End 1108
19477 11 Sep 2021 @ 1400 11 Sep 2021 @ 1410 aferrara 1-1.5' boil in lead up to Grotto that did not result in an eruption of GF
19260 03 Sep 2021 @ 1633 --- Brian Tried to start, jetting began to perhaps 4’ max, then died as Grotto started
18571 22 Jul 2021 @ 0950 --- SteveO 5th Pressure Pool up with boiling in Grotto Fountian.
18570 22 Jul 2021 @ 0913 22 Jul 2021 @ 0917 SteveO 4th Pressure Pool up with boiling 3 to 4 feet in Grotto Fountian. Pressure Pool dropped 0917.
18569 22 Jul 2021 @ 0833 22 Jul 2021 @ 0836 SteveO 3rd Pressure Pool up with boiling in Grotto Fountain. Pressure Pool dropped at 0836
18568 22 Jul 2021 @ 0803 22 Jul 2021 @ 0805 SteveO 2nd Pressure Pool up with Grotto Fountian boil. Pressure Pool dropping at 0805.
18593 22 Jul 2021 @ 0728 22 Jul 2021 @ 0729 BrianR First Pressure Poor up with fountain boil
18592 22 Jul 2021 @ 0701 --- BrianR First appearance of water after Grotto marathon
18794 20 Jul 2021 @ 1511 20 Jul 2021 @ 1538 BrianR Grotto Fountain: First heard water boiling: 15:11 No visible water/boiling before Grotto eruption Pressure Pool up: 15:30-15:31
18791 20 Jul 2021 @ 0818 20 Jul 2021 @ 0916 BrianR Grotto Fountain: First heard water boiling 8:18 Visible water/boiling: 9:01 Pressure Pool up: 9:15-9:16
18776 18 Jul 2021 @ 1623 18 Jul 2021 @ 1737 BrianR First heard water boiling: 16:23 Pressure Pool up: 17:29-17:30 17:34-17:37 Visible water/boiling: 17:28-17:30 17:33-17:36 Did not erupt
18775 18 Jul 2021 @ 1230 18 Jul 2021 @ 1321 BrianR First heard water boiling: 12:30 Visible water/boiling 13:16 Did not erupt
18772 18 Jul 2021 @ 0619 18 Jul 2021 @ 0826 BrianR Hear water boiling 6:19 Pressure Pool up: 6:35-6:39 7:28-7:42 8:11-8:26 Visible water/boiling 6:21-7:42 8:14-8:26 Did not erupt
18069 24 Jun 2021 @ 0850 24 Jun 2021 @ 0856 CrisG pressure pool up. low splashing from cone. pool dropped by 0905.
17770 14 Jun 2021 @ 1235 --- CraigC pressure pool up, Grotto Ftn built up to about 5 foot bursting that collapsed after Grotto started
17769 14 Jun 2021 @ 1225 --- CraigC pressure pool up, light spitting in GF
17747 13 Jun 2021 @ 1352 --- CraigC pressure pool up
17746 13 Jun 2021 @ 1317 --- CraigC pressure pool up
17745 13 Jun 2021 @ 1220 --- CraigC pressure pool up
17716 12 Jun 2021 @ 1654 --- CraigC pressure pool up
17705 12 Jun 2021 @ 1313 --- CraigC pressure pool up
17704 12 Jun 2021 @ 1258 --- CraigC pool has not dropped, completely full now
17703 12 Jun 2021 @ 1120 --- CraigC pressure pool up
17700 12 Jun 2021 @ 1048 --- CraigC water spitting up a few inches, 1053 water visible in pressure pool about 4 inches below top
17695 12 Jun 2021 @ 1000 --- CraigC pressure pool up
17669 11 Jun 2021 @ 1117 --- CraigC pressure pool up
17668 11 Jun 2021 @ 1106 --- CraigC pressure pool up, right back down, low energy
17666 11 Jun 2021 @ 1033 --- CraigC pressure pool up, strong boil from Grotto Fountain
17664 11 Jun 2021 @ 0952 --- CraigC pressure pool up, strong 2 foot boil in Grotto Fountain
17662 11 Jun 2021 @ 0910 --- CraigC pressure pool up
17658 11 Jun 2021 @ 0830 --- CraigC pressure pool up
17656 11 Jun 2021 @ 0752 --- CraigC pressure pool up
17611 09 Jun 2021 @ 1401 --- CraigC pressure pool up
17610 09 Jun 2021 @ 1320 --- CraigC pressure pool up
17609 09 Jun 2021 @ 1309 --- CraigC pressure pool up
17608 09 Jun 2021 @ 1254 --- CraigC pressure pool up
17607 09 Jun 2021 @ 1247 --- CraigC pressure pool up
17606 09 Jun 2021 @ 1157 --- CraigC pressure pool up
17605 09 Jun 2021 @ 1122 --- CraigC pressure pool up
17597 09 Jun 2021 @ 0708 --- CraigC water up in pressure pool, bubbling in Grotto Fountain
17595 09 Jun 2021 @ 0646 --- CraigC brief spitting
17560 07 Jun 2021 @ 1435 --- CraigC pressure pool up
17559 07 Jun 2021 @ 1350 --- CraigC pressure pool up
17558 07 Jun 2021 @ 1304 --- CraigC pressure pool up
17475 05 Jun 2021 @ 1226 --- CraigC pressure pool up
17431 04 Jun 2021 @ 1218 --- CraigC pressure pool up
17430 04 Jun 2021 @ 1203 --- CraigC pressure pool up, splashing in Grotto Geyser
16937 28 Apr 2021 @ 0915 --- CraigC Pressure pool up, small bubbling from GF
16934 27 Apr 2021 @ 1401 --- CraigC Pressure pool up, dropped after entry, then back up at 1405, GF began small bubbling.
16926 26 Apr 2021 @ 1155 --- CraigC Pressure pool up, GF spouting for 5 mins then dropped
16925 26 Apr 2021 @ 1116 --- CraigC pressure pool full, GF spouting 3 to 4 feet variable for 5 mins before collapsing
16086 12 Sep 2020 @ 1352 --- CraigC pressure pool up
16085 12 Sep 2020 @ 1305 --- CraigC pressure pool up
16065 11 Sep 2020 @ 1534 --- CraigC pressure pool is full
15951 04 Sep 2020 @ 1003 --- TheHikingDude pool empty
15929 02 Sep 2020 @ 0811 --- CraigC pressure pool up, small bubbling in GF
15912 31 Aug 2020 @ 1201 --- CraigC pressure pool rising. 1202 bursting in GF
15910 31 Aug 2020 @ 1122 --- CraigC pressure pool up, then fell, small bursting from GF
15909 31 Aug 2020 @ 1040 --- CraigC pressure pool up, just dropped. small bubbling from gf
15719 23 Aug 2020 @ 1247 23 Aug 2020 @ 1413 BrianR Overflowed water at various times in buildup to Grotto eruption, but never boiled. Pressure Pool had visible water ~ 95% of this time frame. This and South Grotto Fountain series of eruptions was due to Spa having a flowing runoff channel to the river and all three of its vents bubbling (I.e., it was trying to start at the same time as Grotto). Also Grotto Central Vents were active in this time frame when South Grotto Fountain was not erupting. Demetri will provide notes on Startling during this time frame
13539 04 Sep 2019 @ 1224 --- c.barwin end time
12835 28 Jul 2019 @ 0938 --- rbwhitaker Got over two feet tall then backed down to nothing
12033 29 Jun 2019 @ 1454 --- Polly Wet around Grotto Fountain.
11992 27 Jun 2019 @ 1712 27 Jun 2019 @ 2007 BrianR After aborted eruption, the Grotto system went into a stalled pattern. Grotto Fountain was in a continuous boil up to 2 ft ( mostly 1 ft and under) from 17:49 to 19:28, 19:34 to 1943, and 19:51 to 19:58. The “pressure pool” was rising and falling just barely in and out of view from 17:20 to 18:51, then staying always in view until Grotto Fountain finally erupted at 20:09. Grotto was silent except for three one minute grumbles during this time. All Spa vents were off and the pool rose only 3 inches during this time.
11991 27 Jun 2019 @ 1708 27 Jun 2019 @ 1711 BrianR 6 to 10 ft eruption aborted, no Grotto
11336 23 May 2019 @ 1420 23 May 2019 @ 1521 Kyle as pressure pool rose and dropped Grotto Fountain bubbled/boiled to a height just above the height of it's cone for brief periods when the pressure pool was full and would stop when pressure pool level dropped
11264 18 May 2019 @ 1348 --- Mkeller Repeat of what happened at 12:56
11265 18 May 2019 @ 1256 --- Mkeller Erupted to 3-4 feet for about 3 minutes. Grotto tried to start. Central Vents erupted instead.
8982 25 Jun 2018 @ 1559 --- BrianR “Pressure Pool” up at 15:59 through 16:06, 263 minutes after last Grotto. Grotto Fountain water to 3 ft at 16:01, no eruption prior to Grotto
8981 25 Jun 2018 @ 1527 --- BrianR “Pressure Pool” up at 15:27 through 15:31 no Grotto Fountain water. 231 minutes after last Grotto
8980 24 Jun 2018 @ 1523 --- BrianR “Pressure Pool” up 15:23 through 15:26, no Grotto Fountain water. 262 minutes after last Grotto
7047 23 Sep 2017 @ 1600 23 Sep 2017 @ 1606 Polly Bubbles increasing to ~6 inches steady, then off 1606.
3517 20 Aug 2016 @ 1931 --- Kitt B Grotto Fountain ended at 1931
2533 11 Oct 2015 @ 1223 --- Siegmund Bubbling vigorously 1223; boiling hard 1228-1231, but never got more than ~30cm high
2151 14 Aug 2015 @ 1312 --- JSJ Blipping at 1312 (Grotto & Rocket started at 1314).
1656 28 May 2015 @ 1448 --- mhreed Saw two distinct steam clouds from F&M. By the time I walked up to the Grotto area, Grotto Fountain was at 10 ft. and dying down. Not sure if missed or aborted eruption.
1612 19 May 2015 @ 1347 19 May 2015 @ 1358 JSJ Intermittent small blipping to very low spouting from 1347 to 1358. No more after Grotto Geyser eruption start at 1358.
1005 29 Aug 2008 @ 0000 29 Aug 2008 @ 2359 BoekelUpload
1352 09 Jun 2007 @ 0900 09 Jun 2007 @ 0909 BoekelUpload 9:0x
3879 03 Jul 2006 @ 0700 03 Jul 2006 @ 1545 Tara Grotto Fountain had been having periodic boiling episodes since sometime before 0700. These episodes alternated with eruptions by South Grotto Fountain. There were three stronger episodes at 0711, 1100, and 1400. These occurred midway between hourly Giant hot periods. When Grotto Fountain finally did erupt, it was weak and lasted only 5 minutes, but Grotto did follow at 1548.
15329 19 Nov 1996 @ 1103 --- JarnoO overflowing heavily ~15-20 gpm
EntrySourceLinkComment
26 Jun 2020 @ 1345 JarnoO https://www.youtube.com/watch?v=u5PSt5bVzBI As seen from the webcam, by LindaG.
04 Jun 2019 @ 1600 Janet Jones https://www.instagram.com/p/ByTruIXgn3S/?igshid=1p95trg6cm06a video - just wow!
06 Jun 2016 @ 1728 JSJ https://www.youtube.com/watch?v=zx8TS3vUBX8#t=5m32s Video compilation (starting at time stamp 5:32) of Grotto Fountain Geyser's 5:28 to 5:50 PM eruption on 6 June 2016.
12 May 2013 @ 1246 JSJ https://www.youtube.com/watch?v=Oezz90AHebA Video by Will Boekel of Grotto Fountain Geyser in eruption at 12:46 PM-onward on 12 May 2013.
27 Jun 2013 @ 1323 JSJ https://www.youtube.com/watch?v=gefNjjZY-vo Video by Will Boekel showing Grotto Fountain Geyser's 1:23 PM-onward eruption on 27 June 2013.
06 Jun 2016 @ 1728 JSJ https://www.flickr.com/photos/jsjgeology/30841241351 Photo (1 of 23) of Grotto Fountain Geyser's 5:28 to 5:50 PM eruption on 6 June 2016.
12 Jul 2013 @ 0835 JSJ https://www.youtube.com/watch?v=n2NnnyK4nYo Video by Micah Kipple of the Grotto Fountain Geyser-South Grotto Fountain Geyser dual eruption during the morning of 12 July 2013.
BaselineDistance (ft)Description
West Side 100Note this one is off trail beyond the bumper logs on a cinder block just beyond the sign on the log to the west side.