Last Known Eruption
189d 12m ago

Interval Statistics

Interval Count34
Min27m
Max6y 10d 9h 36m
Mean198d 21h 54m
Median24d 10h 2m

Latest Notes

Note IDStart Time (US/Mountain)End Time (US/Mountain)EntrantNote
36443 18 Aug 2024 @ 1326 --- Janet Jones Boiling cyclically from the back edge. No boiling at allfrom the edge closest to the boardwalk.
36077 24 Jul 2024 @ 1610 --- JarnoO (wc) The runoff channel beginning east of the vent going directly SSW is starting to show hints of orange. The established runoff channel exiting the pool also has orange returning, though only straight down to the plateau and not its branches. East vent remains active, at times vigorous; pool itself appears flat.
35689 02 Jul 2024 @ 2030 --- K.Cooper Boiling from a different vent than usual. While the normal vent is usually more left on the pool, this is back right when looking at it from the plume bench Behavior is more of a jetting type burst that boil. Activity is consistent at least 6in high, many episodes over three feet
35687 02 Jul 2024 @ 1905 --- JarnoO (wc) I've been looking at it for the last 10 minutes or so, and the only hint at periodicity is that the splashing (originating from the vent at the eastern edge of the pool) gets lower and slightly more spaced apart for a couple of seconds every 10-20 seconds. Otherwise it's in constant state of agitation. Not sure if this is "old news" (it certainly was new to me), but I looked at my captures from yesterday (which never zoomed in on Improbable, unlike with this observation) and it didn't seem to be the case then. Additionally, it appears a new runoff channel has developed in the past couple of weeks/months (maybe too long of a timeframe?), judging by the dark geyserite, which starts east of the active vent and heads immediately SSW to the "bench" on which the bacterial mat has been relocated to.
34110 12 Mar 2024 @ 1908 --- JarnoO (wc) Sudden, tall jet (I estimate about the height of Beehive's Indicator at full force, 10-odd feet or so) as wide as the crater. Otherwise ordinary activity as of writing (1913).
33863 17 Jan 2024 @ 1640 --- K.Cooper lots of large and loud boils. some of which are around 8ft
33476 27 Dec 2023 @ 1515 27 Dec 2023 @ 1520 Delta4Heavy85 (Wc) Mostly small boils with the occasional taller boil up to maybe 1-2 ft.
28196 10 Sep 2023 @ 1708 --- SantaFe108 Appears to be a large stick in Improbable's vent.
26303 14 Jun 2023 @ 1604 --- Graham Just at overflow, filled with milky water. Boiling up to 6 inches on Plume side. Water rising, overflowing down the slope. 1620 some boil surges reaching a foot or two, pre eruptive boil surges were stronger.
26302 14 Jun 2023 @ 1445 --- aferrara Totally empty, boardwalk soaked, smells like the ocean.
26186 09 Jun 2023 @ 0944 --- CrisG nice splash to 5-6ft. Enough to steal my attention from Anemone
25935 31 May 2023 @ 1619 31 May 2023 @ 1626 Delta4Heavy85 Large splashes at 16:21:51, 16:22:14, 16:23:34, 16:24:10 and 16:24:29
25615 20 May 2023 @ 2008 --- Brando Had a ~8 second push to 3-4 feet
25362 08 May 2023 @ 1252 08 May 2023 @ 1320 Delta4Heavy85 Good splashes at 12:57:44, 12:57:57, 13:04:20, 13:06:41, 13:08:15, 13:12:26, 13:16:33, 13:18:39 and 13:20:36
25170 16 Apr 2023 @ 1209 --- Delta4Heavy85 Another good boil, about twice as high as the last two (~10 feet).
25169 16 Apr 2023 @ 1204 --- Delta4Heavy85 Two sizable boils (~5 feet) for ~5s each
24917 16 Jan 2023 @ 0937 --- Delta4Heavy85 (wc) Nice (~4ft) surging and constant low splashing
24785 20 Dec 2022 @ 0759 --- Delta4Heavy85 Splashing
24632 03 Nov 2022 @ 1616 --- Delta4Heavy85 Splashing
24599 31 Oct 2022 @ 1527 --- Delta4Heavy85 Splashing
16887 19 Apr 2021 @ 1523 --- JarnoO 1523:44 through 1524:00 - three tall jets. First jet 1523:44, second 1523:56, third 1523:58. Height of each higher than Anemone-Big's larger play, between 6-10 feet or so with the first and second being the tallest. Third about 6 feet at most. First jet was accompanied by a steam plume which remained attached to the vent for 8 seconds, so some further action must have happened which was obscured by it. Initially assumed to be Anemone-Big because of this play, but this one erupted 4 minutes later. Remained restless in the minutes after.
14661 18 Jun 2020 @ 1532 18 Jun 2020 @ 1552 JarnoO (wc) 1-3 events/minute, mostly 3 events. Events were separated by about 10-20s of quiet (pause) and lasted themselves about equally long. Throughout this note, "same" refers to 1532a and 1533a for behavior. 1532a small boiling ie (¼ to ½ size of regular Anemone-Little play). 1533a boil (about Anemone-Little-sized), then small; 1533b same as 1533a. 1534a same, weak; 1534b same w/ sustained boil. 1535a same; 1535b big boil (Anemone-Big-sized) sustained; 1535c same, small (Anemone-Little-sized is probably generous). 1536a same, small; 1536b same, very small; 1536c same, v. small. 1537a same, small (long, ±15-20-odd seconds); 1537b same, small; 1537c same, small. 1538a same, big; 1538b (cam sync, no event); 1538c same, long. 1539a same, small (long pause ±15s preceded). 1540a same, small; 1540b same, small. 1541a same, small; 1541b same, small; 1541c same, decent start (Anemone-Little-sized), small otherwise. 1542a same, small; 1542b same, small. 1543a same, v. small (long pause ≥±20s preceded); 1543b same, v. small. 1544a same, v. small but picked up in size - lasted >30s; 1544b big start, small otherwise. 1545a same, Anemone-Big-sized start; 1545b same, small. 1546a same, small w/ big boil; 1546b same, sustained. 1547a same, short duration with long pause preceding; 1547b same, short pause. 1548a same, bigger than other events; 1548b same, decent boil on start. 1549a same, small. 1550a same, small (long pause preceded); 1550b same, small. 1551a same, v. small; 1551b same, v.small. 1552 cam panned away, end of observations.
14186 14 May 2020 @ 0919 --- K.Cooper (webcam) Improbable had a very large burst at this time, estimated to be at least 5, likely taller feet, and was sustained for about one second.
11443 31 May 2019 @ 1131 --- TSBryan single burst 4 or 5 feet high
10224 15 Sep 2018 @ 2147 --- Micah Kipple Low surging and roiling as normal. No evidence of major eruption.
10578 10 Sep 2018 @ 1214 --- Polly 2' burst
8658 13 Jun 2018 @ 1400 --- CrisG Nice, wide 2.5-3 ft burst.
8064 03 May 2018 @ 1215 --- Micah Kipple Violent superheated boiling 30-60 cm with some surges to 1.3m
8012 27 Apr 2018 @ 0632 --- Micah Kipple Having nice bursts this morning
7999 25 Apr 2018 @ 1603 --- Micah Kipple Large sudden burst to 3 feet filling most of the pool
7988 22 Apr 2018 @ 1010 --- udo 3 to 4 foot bursts happen randomly. Smaller stuff is nearly constant.
7864 27 Dec 2017 @ 1242 --- novakg Nice 2 foot burst.
5671 03 Sep 2017 @ 1133 --- Pat Snyder 5 foot single burst, wide and surprising! Very cool.
3976 21 Apr 2017 @ 0806 --- Micah Kipple No evidence for recent major eruptions.
3845 04 Nov 2016 @ 1724 --- Betty nice tall burst for 1 second or 2, think about 3-4 ft.
3165 22 Jun 2016 @ 0824 --- David spouting 1-2'. see: https://www.flickr.com/photos/ujelang/27940051561/in/dateposted-public/
3331 22 Jun 2016 @ 0821 --- David observed from 8:21-8:30. In a state of near constant boiling, with max of 1+ ft. See photos: https://www.flickr.com/search/?user_id=93705139%40N00&sort=date-taken-desc&text=improbable%20geyser&view_all=1
3358 11 Jun 2016 @ 1000 11 Jun 2016 @ 1200 JSJ Thermal photography of Improbable Geyser in low perpetual spouting recorded 162° F.
2585 25 Oct 2015 @ 1034 --- Biddle possible eruption seen on webcam
2334 03 Sep 2015 @ 1858 --- bhoppe Huge splash/surge to 5ish feet
2167 19 Aug 2015 @ 0800 --- Micah Kipple Still slightly murky this morning. Teal blue water with a little more vigorous boiling than normal. No evidence of a followup eruption overnight.
2129 16 Aug 2015 @ 0800 16 Aug 2015 @ 0853 Micah Kipple Lots of strong boiling this morning. A couple "almost minors" to 4 feet, and at 0853 there was a botryoidal-like bubble to 2 feet that was spectacularly beautiful, if not startling.
1888 11 Jul 2015 @ 1530 11 Jul 2015 @ 1710 Micah Kipple Improbable had several large episodes of violent boiling over the west (new vent) that I observed during this time period. Some of the surges were 3 feet tall and just as wide and sent a small flood or runoff down it's channels.
1510 18 Jan 2015 @ 0730 --- mhreed Snow marker placed in the late afternoon on the 17th was missing. Possible that the snow simply melted due to warm ground/warm air temperature, but ice chunks completely gone leading me to speculate that it may have had an event overnight. Pool color is completely back to normal.
1507 17 Jan 2015 @ 0740 --- WillBoekel snow marker still in place from last night. and the pool color is starting to clear
1185 08 Jul 2014 @ 0800 08 Jul 2014 @ 1800 JSJ Improbable Geyser in eruption during late morning & early afternoon on 8 July 2014 - doing its usual moderately low perpetual spouting.
1198 03 Jun 2014 @ 1200 --- JSJ Improbable Geyser was doing its usual, moderately-low perpetual spouting - observed around noon time on 3 June 2014.
2713 10 Aug 2013 @ 1444 --- JSJ Improbable Geyser was engaged in its usual, moderately low perpetual spouting behavior - observed in the middle & late afternoon of 10 August 2013.
Baseline does not exist.