Last Known Eruption
71d 4h 17m ago

Latest Eruptions

Eruption DurationInterval
07 Aug 2021 @ 125816m
07 Aug 2021 @ 12424m
07 Aug 2021 @ 12383h 58m
07 Aug 2021 @ 08401m
07 Aug 2021 @ 08391m
07 Aug 2021 @ 08381m
07 Aug 2021 @ 083711m
07 Aug 2021 @ 082627m
07 Aug 2021 @ 0759 ie64d 21h 52m
03 Jun 2021 @ 100719h 17m
02 Jun 2021 @ 14501m
02 Jun 2021 @ 14492m
02 Jun 2021 @ 14473m
02 Jun 2021 @ 14441m
02 Jun 2021 @ 14432m
02 Jun 2021 @ 14411d 3h 10m
01 Jun 2021 @ 11311d 14h 53m
30 May 2021 @ 20382m
30 May 2021 @ 20361m
30 May 2021 @ 20351m
30 May 2021 @ 20343m
30 May 2021 @ 20313m
30 May 2021 @ 20281m
30 May 2021 @ 20272m
30 May 2021 @ 20259m
30 May 2021 @ 20162m
30 May 2021 @ 20144m
30 May 2021 @ 20102m
30 May 2021 @ 20082m
30 May 2021 @ 20062m
30 May 2021 @ 20041m
30 May 2021 @ 20031m
30 May 2021 @ 20026m
30 May 2021 @ 19563m
30 May 2021 @ 19533m
30 May 2021 @ 19509m
30 May 2021 @ 19411d 8h 14m
29 May 2021 @ 11271 burst3m
29 May 2021 @ 11241 burst2m
29 May 2021 @ 11221 burst3m
29 May 2021 @ 11191 burst3m
29 May 2021 @ 11161 burst6m
29 May 2021 @ 11101 burst10d 2h 42m
19 May 2021 @ 08283m
19 May 2021 @ 08254m
19 May 2021 @ 08211m
19 May 2021 @ 08206m
19 May 2021 @ 08143m
19 May 2021 @ 08112m
19 May 2021 @ 08095m
19 May 2021 @ 08041y 261d 20h 39m
31 Aug 2019 @ 112524d 17h 17m
06 Aug 2019 @ 18082m
06 Aug 2019 @ 18062m
06 Aug 2019 @ 18043m
06 Aug 2019 @ 18012m
06 Aug 2019 @ 17594m
06 Aug 2019 @ 17557m
06 Aug 2019 @ 17482m
06 Aug 2019 @ 17462m
06 Aug 2019 @ 174412m
06 Aug 2019 @ 17323m
06 Aug 2019 @ 17291m
06 Aug 2019 @ 17282m
06 Aug 2019 @ 17262m
06 Aug 2019 @ 1724~2s 6m
06 Aug 2019 @ 17183m
06 Aug 2019 @ 17153m
06 Aug 2019 @ 17121m
06 Aug 2019 @ 171122m
06 Aug 2019 @ 16492m
06 Aug 2019 @ 16474m
06 Aug 2019 @ 16432m
06 Aug 2019 @ 16413m
06 Aug 2019 @ 16381m
06 Aug 2019 @ 16371m
06 Aug 2019 @ 16362m
06 Aug 2019 @ 16341m
06 Aug 2019 @ 16332m
06 Aug 2019 @ 16312m
06 Aug 2019 @ 16292m
06 Aug 2019 @ 16272m
06 Aug 2019 @ 16254m
06 Aug 2019 @ 16214m
06 Aug 2019 @ 16176m
06 Aug 2019 @ 16112m
06 Aug 2019 @ 16097m
06 Aug 2019 @ 16025m
06 Aug 2019 @ 15571m
06 Aug 2019 @ 15562m
06 Aug 2019 @ 15541m
06 Aug 2019 @ 15531m
06 Aug 2019 @ 15522-3s2m
06 Aug 2019 @ 15506m
06 Aug 2019 @ 15442m
06 Aug 2019 @ 15423m
06 Aug 2019 @ 15392m
06 Aug 2019 @ 15375m
06 Aug 2019 @ 15323m
06 Aug 2019 @ 15291m

Interval Statistics

Interval Count100
Min1m
Max1y 261d 20h 39m
Mean7d 7h 39m
Median3m

Latest Notes

Note IDStart Time (US/Mountain)End Time (US/Mountain)EntrantNote
17197 26 May 2021 @ 1800 26 May 2021 @ 1858 JSJ In very light roiling and/or light bubbling at 1800. Small, brief doming at 1858.
13099 07 Aug 2019 @ 1900 07 Aug 2019 @ 1926 JSJ No activity at all from Middle Sister, but I've seen pauses much longer than this recently. No other activity in the entire Three Sister complex, except Three Crater eruptions.
13083 06 Aug 2019 @ 1505 06 Aug 2019 @ 1808 JSJ All closed intervals. Occasional blipping or roiling in lieu of an eruption. All eruptions were single brief bursts, with one double burst. One or two were ~2-3 seconds in duration.
13054 05 Aug 2019 @ 1203 05 Aug 2019 @ 1341 JSJ All closed intervals. Some roiling and blipping events. All eruptions were single short bursts of varying sizes.
13027 04 Aug 2019 @ 1027 04 Aug 2019 @ 1625 JSJ All closed intervals. Under constant observation during this time.
12384 06 Jul 2019 @ 1305 --- DanS Domed water. Did not erupt.
9091 09 Jul 2018 @ 1145 09 Jul 2018 @ 1218 Micah Kipple Occasional bubbling vent just on the south edge of the crater towards south sister.
5288 23 Aug 2017 @ 1117 23 Aug 2017 @ 1155 Tara Under observation during this time, no eruptions.
14373 31 Aug 1995 @ 0000 31 Aug 1995 @ 2359 JarnoO active
EntrySourceLinkComment
06 Aug 2019 @ 1505 JSJ https://www.youtube.com/watch?v=_iWPkqVV0Sc#t=4m02s Clips 17-37 of this video compilation (= time stamp 4:02 to the end) show Middle Sister Spring eruptions on 6 August 2019.
04 Aug 2019 @ 1027 JSJ https://www.youtube.com/watch?v=_iWPkqVV0Sc Clips 1-16 of this video compilation (= beginning to time stamp 4:01) show Middle Sister Spring eruptions on 4 August 2019.
Baseline does not exist.