Last Known Eruption
6y 220d 11h 59m ago

Latest Eruptions

Eruption DurationInterval
22 Aug 2017 @ 144875d 23h 6m
07 Jun 2017 @ 15421y 292d 3h 8m
20 Aug 2015 @ 123466d 19h 14m
14 Jun 2015 @ 172065y 13d 16h 20m
17 Jun 1950 @ 0000 A

Interval Statistics

Interval Count4
Min66d 19h 14m
Max65y 13d 16h 20m
Mean16y 294d 15h 27m
Median1y 1d 13h 7m

Latest Notes

Note IDStart Time (US/Mountain)End Time (US/Mountain)EntrantNote
33117 19 Dec 2023 @ 1507 --- mhreed Activity appears unchanged. Clusters of thumps at variable intervals (on the order of minutes) and variable strength.
28212 11 Sep 2023 @ 1104 --- Pholli black sand pool had an eruption of ~5ft following a very large thump!
26906 08 Jul 2023 @ 1450 --- nails Thumping
26877 07 Jul 2023 @ 0847 --- nails Thumping
26343 15 Jun 2023 @ 1554 --- CrisG thumping
26193 09 Jun 2023 @ 1423 --- CrisG thumping
23711 10 Sep 2022 @ 1549 10 Sep 2022 @ 1603 ThomasR Strong thumps at 1550 and 1600 with large boiling up to approx. 1 foot. Smaller boils with weak thumps in between.
19427 10 Sep 2021 @ 1201 --- CrisG thumping
19062 25 Aug 2021 @ 1520 25 Aug 2021 @ 1550 BrianR 5 good thumping episodes, one with 4 ft boil
18437 15 Jul 2021 @ 1658 15 Jul 2021 @ 1708 nails Thumping.
18136 25 Jun 2021 @ 1001 --- CrisG great thumping with nice boil at 1001
18166 25 Jun 2021 @ 1001 --- CrisG great thumping with nice boil at 1001
16207 20 Sep 2020 @ 1743 --- DanS Thumps and vigorous multipoint boils
16151 17 Sep 2020 @ 1037 --- kc 7 ft burst in the middle of Pool. No thumps prior.
16111 13 Sep 2020 @ 1610 --- Graham Watched for 15m and no noisy thumps. Could feel some vibration on the railing. Sinter rim is dry indicating no high water.
14979 14 Jul 2020 @ 1033 --- nails Thumping
14098 23 Jan 2020 @ 1144 --- Graham Big thumps 1144, 1150, 1151, 1157 with big boil.
11477 01 Jun 2019 @ 1432 --- kc Almost entire pool burst violently to about 7 feet. Several big chunks of edge broke off. Total surprise. Thump happened as it was calming.
11388 27 May 2019 @ 1515 27 May 2019 @ 1549 StephH Good thumps and bubbles every four to seven minutes.
10796 25 Dec 2018 @ 1500 --- Janet Jones Visitor report that mild thumps were happening every 3-5 minutes.
10005 03 Sep 2018 @ 1230 --- BobInSLC 6-8 foot boil, after 45 minutes of waiting. thumping every 4 minutes or so.
8410 02 Jun 2018 @ 1026 --- kc Wide boil over 12 feet. Broke off multiple big chunks of edge. Was preceded by a mild thump.
8407 02 Jun 2018 @ 0720 --- steve Black sand pool is less active. I observed it from 0720 to 0752. I had no thumps until 0737 when I had 3 thumps followed by a boil. Just after that was one thump followedby a stronger boil. At 0745 there was one thump and a boil. At 0747 was a thump with no boil. At 0750 was a strong boil without a thump. Then at 0751 was a strong thump with no boil.
4053 06 May 2017 @ 0957 --- sfavor intermittent boiling. very nice shade of blue today.
2786 24 Apr 2016 @ 1448 --- User34 Thumps and heavy boiling
2747 17 Apr 2016 @ 1145 --- mhreed Thump cycles every 1-8 minutes, with one exceptionally loud cycle causing boiling to 2+ feet.
2166 20 Aug 2015 @ 1013 --- Choward There was a tree trunk floating in the pool. thumps every 2-3 minutes.
1188 08 Jul 2014 @ 1200 08 Jul 2014 @ 1800 JSJ Black Sand Pool is still having relatively frequent subterranean thumping, followed by moderately small to moderately large roiling in Black Sand Pool - observed mid-afternoon on 8 July 2014.
1067 11 May 2014 @ 0000 11 May 2014 @ 2359 WillBoekel Still nicely thumping :)
1217 02 Jun 2013 @ 0000 02 Jun 2013 @ 2359 JSJ Black Sand Pool - moderately frequent subterranean thumping.  Each thumping event was followed by energetic roiling-boiling at the surface of the pool, lasting for about 15 seconds or so.
15829 31 May 1997 @ 0827 --- JarnoO murky H2O; visibility ≤1ft
No attachments for this geyser.
Baseline does not exist.