Last Known Eruption
3y 357d 16h 36m ago

Latest Eruptions

Eruption DurationInterval
12 Jul 2016 @ 173711d 21h 32m
30 Jun 2016 @ 200530d 1h 25m
31 May 2016 @ 18403h 41m
31 May 2016 @ 14595m 26m
31 May 2016 @ 1433423m
31 May 2016 @ 1410527m
31 May 2016 @ 1343323m
31 May 2016 @ 132026m
31 May 2016 @ 125423m
31 May 2016 @ 123142y 277d 20h 52m
27 Aug 2013 @ 153917y 247d 3h 28m
28 Dec 1995 @ 111125m
28 Dec 1995 @ 10461d 1h 30m
27 Dec 1995 @ 091621h 6m
26 Dec 1995 @ 1210 ie33m
26 Dec 1995 @ 11372h 1m
26 Dec 1995 @ 0936 ie21h 33m
25 Dec 1995 @ 120324m
25 Dec 1995 @ 11393d 17m
22 Dec 1995 @ 112217m
22 Dec 1995 @ 1105 ie17m
22 Dec 1995 @ 1048 ie1d 35m
21 Dec 1995 @ 1013 ie53m
21 Dec 1995 @ 092023h 48m
20 Dec 1995 @ 093219h 50m
19 Dec 1995 @ 13422h 50m
19 Dec 1995 @ 105214m
19 Dec 1995 @ 1038 ie20h 20m
18 Dec 1995 @ 1418 ie19m
18 Dec 1995 @ 135910m
18 Dec 1995 @ 13491d 1h 43m
17 Dec 1995 @ 120614m
17 Dec 1995 @ 115221h 40m
16 Dec 1995 @ 141213m
16 Dec 1995 @ 13591d 2h 32m
15 Dec 1995 @ 11271h 59m
15 Dec 1995 @ 0928 ie49m
15 Dec 1995 @ 08395d 22h 6m
09 Dec 1995 @ 103321h 40m
08 Dec 1995 @ 1253 ie1y 185d 2h 23m
06 Jun 1994 @ 11307d 23h 35m
29 May 1994 @ 1155262d 18h 52m
08 Sep 1993 @ 170321d 2h 11m
18 Aug 1993 @ 145221m
18 Aug 1993 @ 143129m
18 Aug 1993 @ 140239d 5h 27m
10 Jul 1993 @ 0835268d 13h 58m
14 Oct 1992 @ 1837 ie71d 22m
04 Aug 1992 @ 18151d 21h 58m
02 Aug 1992 @ 2016:5011m 38s
02 Aug 1992 @ 2005:1211m 38s
02 Aug 1992 @ 1953:3411m 25s
02 Aug 1992 @ 1942:0911m 50s
02 Aug 1992 @ 1930:1911m 22s
02 Aug 1992 @ 1918:5712m 7s
02 Aug 1992 @ 1906:507h 32m 35s
02 Aug 1992 @ 1134:1512m 5s
02 Aug 1992 @ 1122:1012m 20s
02 Aug 1992 @ 1109:5012m 20s
02 Aug 1992 @ 1057:3011m 34s
02 Aug 1992 @ 1045:5616m 21s
02 Aug 1992 @ 1029:3511m 35s
02 Aug 1992 @ 1018:0012d 16h 55m 11s
20 Jul 1992 @ 1722:4910m 16s
20 Jul 1992 @ 1712:3310m 33s
20 Jul 1992 @ 1702:009m 7s
20 Jul 1992 @ 1652:5319d 20h 49m
30 Jun 1992 @ 200311m
30 Jun 1992 @ 195211m
30 Jun 1992 @ 194111m
30 Jun 1992 @ 193010m
30 Jun 1992 @ 19207d 5h 55m
23 Jun 1992 @ 13254d 1h 58m
19 Jun 1992 @ 112712m
19 Jun 1992 @ 111522m
19 Jun 1992 @ 105312m
19 Jun 1992 @ 104115y 358d 16h 13m
29 Jun 1976 @ 1828 ie3h 28m
29 Jun 1976 @ 1500 ie1h 35m
29 Jun 1976 @ 1325 ie1y 7d 20h 7m
22 Jun 1975 @ 17181h 47m
22 Jun 1975 @ 15311y 317d 18h 59m
08 Aug 1973 @ 20324d 23h 20m
03 Aug 1973 @ 21121d 1h 26m
02 Aug 1973 @ 194620d 20h 53m
12 Jul 1973 @ 225313m
12 Jul 1973 @ 22408m
12 Jul 1973 @ 22324m
12 Jul 1973 @ 22281d 23h 59m
10 Jul 1973 @ 222944m
10 Jul 1973 @ 21458m
10 Jul 1973 @ 213715m
10 Jul 1973 @ 21228m
10 Jul 1973 @ 211427d 11h 14m
13 Jun 1973 @ 10004m
13 Jun 1973 @ 095613m
13 Jun 1973 @ 0943291d 16h 36m
25 Aug 1972 @ 17078m
25 Aug 1972 @ 16598m
25 Aug 1972 @ 16518m

Interval Statistics

Interval Count100
Min4m
Max17y 247d 3h 28m
Mean160d 6h 29m
Median31m

Latest Notes

Note IDStart Time (US/Mountain)End Time (US/Mountain)EntrantNote
7727 21 Oct 2017 @ 1315 21 Oct 2017 @ 1450 DanS No eruptions in Three Sisters group 1315-1450.
7418 26 Sep 2017 @ 1253 --- Tara Bacteria has returned to the Mugwump side of North Sister. Middle Sister remains active.
5220 22 Aug 2017 @ 1040 22 Aug 2017 @ 1150 Tara Middle Sister is active today and was probably active prior to this based on observations from me, Rocco Paperiello, and David Schwarz, who saw one eruption on 8/21/17. Middle Sister eruptions consist of a single burst that may vary in height from 2 to 8 feet. Mugwump has been inactive for a number of days but is still hot. MYR-1 has been seen boiling but no eruptions have been reported. Three Crater is still frequent and sometimes having energetic eruptions to as much as 6-8 feet.
4880 11 Aug 2017 @ 1220 11 Aug 2017 @ 1321 JSJ Overflow from North Sister's basin caused by splashing eruptions of Three Crater Geyser. Trickling overflow also occurs intermittently between eruptions through a border notch just north of Mugwump Geyser.
4873 10 Aug 2017 @ 1710 --- Tara Something is erupting in North Sister that was creating some overflow as of 8/8/17, though less runoff than when Mugwump was active in 2016. The bacteria in Mugwump was present at that time but is now gone. i have yet to catch the erupting feature so I am not sure if it is Mugwump, MYR-1, or something else.
3496 14 Aug 2016 @ 1733 14 Aug 2016 @ 1751 JSJ Well-developed steamnado over the Three Sisters Spring complex at 1733. Another one at 1751.
3005 07 Jun 2016 @ 1708 07 Jun 2016 @ 1711 JSJ Heavy pulsing event from North Sister Spring (= vent at 44°, 27' 37.08" North latitude, 110° 50' 12.71" West longitude) from 1908 to 1911.
14456 31 Dec 1995 @ 1200 --- JarnoO not observed since 12/28; {generic time}
497 06 Oct 1975 @ 0000 06 Oct 1975 @ 2359 BoekelUpload Three Sisters area springs;1st overflow since 6/30/75 Tremor
No attachments for this geyser.
Baseline does not exist.


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