Last Known Eruption
56y 291d 12h 44m ago

Latest Eruptions

Eruption DurationInterval
23 Aug 1967 @ 08454d 3h 45m
19 Aug 1967 @ 0500 A

Interval Statistics

Interval Count1
Min4d 3h 45m
Max4d 3h 45m
Mean4d 3h 45m
Median4d 3h 45m

Latest Notes

Note IDStart Time (US/Mountain)End Time (US/Mountain)EntrantNote
34699 26 May 2024 @ 0804 --- ypcaribou Abdolutely clear turquoise blue.Full.
34259 19 Apr 2024 @ 1533 --- MAB Beautiful clear blue!!! - quite full up into the little cove but couldn't see water level in there due to light and steam - not full enough to top the NE ledge by that nearby vent
29030 22 Oct 2023 @ 0854 --- SantaFe108 ~1½ feet below the alcove roof, bubbling in many places with cloudy green water.
28971 21 Oct 2023 @ 1529 --- JR 2 feet below rim. A murky green, a bit opaque. Slight bubbling.
28926 20 Oct 2023 @ 1608 --- MAB greenish fairly clear - dropped lower to bottom quarter of the wall cove - LOTS bubbles from several points - more on right side - YELLOW MUD SPRING behind it had a solid large area of upwelling - usually fairly cool back there!
28765 14 Oct 2023 @ 1317 --- SantaFe108 Water level into the alcove, clear and blue.
28788 14 Oct 2023 @ 1220 --- MAB clear
28634 05 Oct 2023 @ 1200 --- cb turquoise blue, calm & 1' below high water mark!
28505 26 Sep 2023 @ 1717 --- MAB Clear blue-green and quiet - water level more than halfway up the cove on ~SW side
27294 28 Jul 2023 @ 2038 --- SantaFe108 Water level half-way up the cove and spectacularly clear and blue.
26827 04 Jul 2023 @ 0859 --- MAB clear pretty- water halfway up the cove
25964 02 Jun 2023 @ 1032 --- Tara clear and beautiful pale blue, water level just above overhang on right side
25861 28 May 2023 @ 1950 --- SantaFe108 Brilliant blue clear water. Water level just up to the cove on the left of the pool. Far right vent is dry.
25661 21 May 2023 @ 1435 --- SantaFe108 Spectacular blue color. Water level up to right inside the little cove on the left. Far right vent is dry.
24402 15 Oct 2022 @ 0953 --- MAB half full and into the cove on wall - clear blue green and calm
24250 05 Oct 2022 @ 1229 --- cb Not much change, pool is about 3" lower than last observation. color is deep blue and pool is calm & clear
23961 20 Sep 2022 @ 1635 --- ypcaribou Clear, deep blue. Water tops out about 1 ft down from rim. This one wins the clearest bluest award for today's walkabout.
23499 31 Aug 2022 @ 1120 --- cb Steaming, calm, blue, (visitor just said Listerine blue) high. water is halfway up into the alcove toward NBK-8.
22983 02 Aug 2022 @ 1029 --- cb Only change is the clarity of the pool. A bit more cloudy. pool level is just at the bottom of the cave on the west end.
22919 27 Jul 2022 @ 1614 --- MAB pretty blue color filled halfway up the inner cave like area - calm - little vent nearby the right edge still high and dry
22318 04 Jul 2022 @ 1439 --- cb pool down 8" at least, calm and beautiful blue color
22117 25 Jun 2022 @ 1133 --- cb calm, clear, deep blue color and same pool level as last observation. water is up to & covering the small cave on the west edge
21607 31 May 2022 @ 1453 --- cb pool level also very high, up to & covering the alcove on the west edge of the pool. water is clear & calm. no boil.
21329 16 May 2022 @ 1110 --- Tara Clear and blue, water level just at the overhang on the left side.
21012 18 Apr 2022 @ 1716 --- MAB Clear blue in color about half full - nearly to the top of the SW cove vent but not full enough to connect with the NE sulphury vent
20295 04 Nov 2021 @ 1225 --- MAB higher water than this summer - over that inner ledge but still only about half full
20054 19 Oct 2021 @ 1404 --- cb pool is higher, covering the rock point. has a few small bubblers in the pool.
19810 30 Sep 2021 @ 1235 --- cb Same water level. pool is emerald green in color, calm, mostly clear & steamy. #7 pool is cloudy greenish color, calm & #8 is yellowy in color with a 4" blooping boil on the edge toward Yellow Funnel spring & it is not in overflow.
19607 16 Sep 2021 @ 1032 --- cb water level is ~2.5' below the rim. Water is amazingly clear, green in color and steaming
19625 16 Sep 2021 @ 0929 --- MAB low - water still clear
19372 08 Sep 2021 @ 1135 --- Tara Clear greenish water, calm, down 3'
18506 18 Jul 2021 @ 1048 --- cb Pool has dropped another ~3". Opalescent blue with a slight yellowy tinge on the edges
18327 09 Jul 2021 @ 1330 --- MAB still low low low - opalescent blue - down 3 ft - that little vent on the shelf on the NE side that would dribble sulphur into Mud is still high and dry
18184 29 Jun 2021 @ 1323 --- cb no change in water level. no boil or bubbles, color is a milky opalescent blue
17724 12 Jun 2021 @ 1620 --- MAB 4 feet below high water marks- incredibly low
17574 08 Jun 2021 @ 1112 --- cb water level up 6" since last observation. color is opalescent turquoise blue and calm
17277 30 May 2021 @ 1554 --- cb very low, 1.5 - 2' below smooth water mark on the north rim. The rock outcropping that sticks out into the pool is barely covered with water. pool is a opalescent milky turquoise blue in color and calm.
16395 10 Oct 2020 @ 1020 --- cb same as as last observation. Water is calm and turquoise blue.
16342 06 Oct 2020 @ 1224 --- cb water level is down 2' from the rim of the pool. It is steamy, ( 65°today) clear and blue in color. Pool appears lower by a few inches than I observed last time.
16271 26 Sep 2020 @ 1626 --- cb water level is about 2' down from the rim. This is about 4" down from my observation 3 weeks ago. Pool is calm, blue green in color and has no bubbles or boil
29158 30 Jul 2020 @ 1200 --- research-mab 7/30/2020 - no time noted-- Big Pool S of Mystic {Mud Spring? ← written in} – dramatic color change! Much darker green not turquoise
13253 14 Aug 2019 @ 1615 --- cb up a tad bit but still a good 2'+ down from the rim. (not overflow) Covering the rock peninsula on the south edge inside the pool. it is a milky blue color and calm.
12996 03 Aug 2019 @ 0839 --- cb down 8". greenish blue in color
12970 02 Aug 2019 @ 0938 --- MAB pretty green- water level still low
11023 20 Apr 2019 @ 1035 --- MAB Low, very low water, but a pretty greenish color. Clear.
9967 31 Aug 2018 @ 1034 --- MAB Nearly full, well over the shelf on the east. Not quite up to the sulfur-y vents yet, but much more water. Clear, beautiful blue water
9622 10 Aug 2018 @ 1339 --- MAB LOW water, clear beautiful blue.
29620 02 Aug 2017 @ 1200 --- research-mab 8/02/2017 - no time noted - Mud Spring, south of Mystic Spring has changed from a blue color to more of a green color.
29614 23 Jul 2017 @ 1200 --- research-mab 7/23 - no time noted - (possibly Mud Sp? mab) - Moon= low pools? The pool just west of Mystic Spring is ~2 ft down than normal
29592 25 Aug 2016 @ 1200 --- research-mab 8/25/2016 - no time noted - Mud Spring has changed color to a clear sapphire blue, very pretty
2789 24 Apr 2016 @ 1500 --- sfavor Mud Spring looked like it had a large eruption with spray approximately 30' uphill.
29777 30 Aug 2007 @ 1200 --- research-mab 8/30/2007 .- no time noted - • The usually quite clear and murky pools between Echinus and Puff’n Stuff were turbulent – small areas of water gushing in the pools about 6-12 inches.
30130 18 Aug 1995 @ 1200 --- research-mab 8/18/95 - no time noted - Emerald Pool is no longer having the heavy boils seen since the beginning of disturbance on the 29th.Water levels remain lower than “usual” & heavy boils continue in Crater, Mystic & Mud Springs.
30299 07 Sep 1993 @ 1200 --- research-mab Sept 7 1993 - no time noted - Also Mud Spring & Mystic spring low. [NOTE during these years there was confusion about Mystic, Mud and NBK8 so very few single entries will be entered here - A note containing both will work - mab]
31004 18 Jul 1984 @ 1200 --- research-mab 7/18/1984 Thermal Observations - no time noted - Mud Spring – active 184º
31096 21 May 1983 @ 1200 --- research-mab May 21 1983 – no time noted ~afternoon - Mud Spring – Translucent grey, heavy boiling from the cente
31304 08 Jul 1982 @ 1200 --- research-mab 7/8/1982 - “About 1200” - Mud Spring – muddy, splashing boiling, cloudy green-grey
31288 07 Jul 1982 @ 1200 --- research-mab 7/7/1982 - no time noted - Mud pool & others nearby = constant bubbling
31262 10 Jun 1982 @ 1200 --- research-mab 6/10-82- no time noted - Mud Spring 171°F not overflowing, muddy grey/tan
31232 20 Feb 1982 @ 1200 --- research-mab February 20 1982 - no time noted - Mud Spring 188° green-brown medium turbid H2O that is much clearer than normal.
31177 14 Jan 1982 @ 1200 --- research-mab January 14th 1982 - no time noted - Mud Spring 152° bright green slightly turbid
31536 30 Aug 1981 @ 1200 --- research-mab Sunday August 30 1981 - no time noted - Mud Spring gray turbid H2O bubbling to 8” 179°
31452 02 Aug 1981 @ 1200 --- research-mab Sunday August 2 1981 The Basin Wide Disturbance has occurred! - no time noted - Mud Spring Light green turbid opalescent water that is constantly bubbling 158°
31416 06 Jun 1981 @ 1200 --- research-mab Saturday June 6 1981 - no time noted - Mud Spring – gray-beige, calm, no overflow 171 F
31739 07 Sep 1980 @ 1200 --- research-mab Sunday Sept 7 1980 - no time noted - Mud Spring – periodic boiling to 1 foot, turbid blue-green – evidence of slight overflow 179°F
31702 16 Aug 1980 @ 1200 --- research-mab Sat Aug 16 - no time noted - Mud Spring- Cloudy green and gently bubbling. No overflow. 170°F
31638 09 Jun 1980 @ 1200 --- research-mab June 9 1980 - no times - observations made over the week and entered on 9th - Mud Spring- opaque green and bubbling 169ºF
32024 11 Oct 1979 @ 1200 --- research-mab October 11 1979 – no time noted - Back Basin...changes since disturbance. Mud Spring is very turbid and is a grey-green instead of aquamarine.
32007 28 Sep 1979 @ 1200 --- research-mab September 28 1979 - no time noted - Mud Spring – 177ºF, pale, opaque aquamarine, very gentle boiling
31897 17 Aug 1979 @ 1200 --- research-mab Aug 17 1979 - no time noted - Mud Spring - 169ºF – aqua-marine color
31828 03 Jun 1979 @ 1200 --- research-mab June 3 1979 - no time noted - Mud Spring is still clearing as is Phillips Cauldron.
31825 27 May 1979 @ 1200 --- research-mab May 27 1979 - no time noted - Mud Spring is clearer today and still beautifully blue
32049 25 Mar 1978 @ 1200 --- research-mab March 25 1978 - no time noted - Mystic & Mud Springs – full of water, clear blue & beautiful!
32304 19 Aug 1977 @ 1200 --- research-mab 08/19/1977 - no time noted - changes- Mud Spring is opaque and still retains its color. Decker Geyser is boiling in many spots. Emerald Spring has extended its area of boiling along the edge parallel to the trail and is murky.
32290 18 Jul 1977 @ 1200 --- research-mab 07/18/1977 - no time noted - Yellow Funnel and Mud Springs are clearer than I’ve seen for a few days. .
32278 08 Jul 1977 @ 1200 --- research-mab 07/08/1977 - no time noted - Yellow funnel and Mud Spring were murkier than previously this summer.
32481 15 Aug 1976 @ 1200 --- research-mab 08/15/1976 - no time noted - Root Pool and Green Dragon Spg & Muddy Spg. Both bubbling quite vigorously and quite turbid. A call to Old Faithful visitor center verified the hypothesis that the park had a slight tremor which caused the aforementioned change in B. Basin Spg activity.
32457 31 Jul 1976 @ 1200 --- research-mab 07/31/1976 - no time noted - Mud Spring – appears to be clearing.
32451 27 Jul 1976 @ 1200 --- research-mab 07/27/1976 - no time noted - Mud Spring water level down about 4 feet
32444 24 Jul 1976 @ 1200 --- research-mab 07/24/1976 - no time noted - Mud Spring: is muddy!!
32842 24 Sep 1973 @ 1200 --- research-mab 09/24/1973 - no time noted - Back Basin - Water levels up in those springs which have been low: Yellow Funnel, Phillips Cauldron, Mud Spring (now rather clear blue-green), Mistic [sic] -levels seen up ~6” - - which is ~ down from the normal (high water mark) level except for Phillips Caldron which is about 10” below high water mark.
32806 11 Sep 1973 @ 0900 --- research-mab 09/11/1973 Back Basin 900 am - Water levels seem somewhat lower in features showing that state – mainly: Mystic, Dishwater S, Phillips Cauldron, Mud S., Yellow Funnel; drainage pools near Dishwater have water only in the depressions – the flatter areas have the water.
32801 08 Sep 1973 @ 1200 --- research-mab 09/08/1973 - Back Basin 8:30 am -Water levels low: Mystic, Mud, Phillips, Yellow Funnel
32787 03 Sep 1973 @ 0900 --- research-mab 09/03/1973 - no specific times - Back Basin 900am - Muddy Spring (low) Mystic Spring (low)
32777 02 Sep 1973 @ 1115 --- research-mab 09/02/1973 - no specific time noted - Back Basin at 1115am - Water levels low in Mystic (fairly clear), Mud Spring (fairly clear- down ~ 1’), Yellow Funnel Spring (muddy), pool area (w/mud) to NE of Dishwater Spring, Green Dragon (still a couple of inches down & churning muddy), Pearl Spring w/little runoff; Bathtub;
32763 29 Aug 1973 @ 1200 --- research-mab 08/29/1973 - no time noted - Back Basin @ 8:am Green Dragon is still brown; water level down in Mystic Springs (sev inches), and down in Spring to S.W. (maybe ½’).{Mud Spring? mab}
20376 09 Sep 1972 @ 1200 --- research-mab 09/09/1972 Mud Spring & “Yellow Green Pool” to the east have started to refill. [generic day time]
32921 07 Sep 1972 @ 1200 --- research-mab 09/07/1972 - no time noted - Although the water level seems to be returning to “normal” in most features in the Porcelain Basin, many of the features in the Back Basin (ie Mud, Mystic, Yellow Funnel and Dishwater springs, corporal geyser & Dog Leg) are still low, turbulent and muddy.
32920 02 Sep 1972 @ 1200 --- research-mab 09/02/1972 - no time noted - Mud Spring – water now down 13 inches turbid bubbling brn – up to 3 feet.
32918 31 Aug 1972 @ 1200 --- research-mab 08/31/1972 - no time noted - Mud Spring has had several bursts around 3 feet in height today.
32913 30 Aug 1972 @ 1200 --- research-mab 08/30/1972 - no time noted - Water level is continuing to drop in Congress Pool, the Whale’s Mouth, and the spring to the NE of it, Crackling Lakes Springs, Mud Spring, Dishwater Spring, & Yellow Funnel Spring.
20491 23 Aug 1972 @ 1200 --- research-mab 08/23/1972 -no time noted - Mud Spring - water level is continuing to drop & the bubbling action in the pool is occasionally reaching up to 2 feet [generic time]
33245 13 Aug 1972 @ 1200 --- research-mab 1972 - no time - The Aug 9 activity dropped the water about 8 inches and water was a light gray on Aug 13.
32895 16 May 1972 @ 1200 --- research-mab 05/16/1972 - no time noted - Mud Spring – clear, beautiful blues and yellow ledges - 184º
32972 05 Oct 1971 @ 1200 --- research-mab 10/05/1971 - no time noted - Water levels are down in the following features from the normal level (before 9/9/71) by the following amounts: Mud Spring down 16 inches
32970 04 Oct 1971 @ 1200 --- research-mab 10/04/1971 - no time noted - Additional changes noted included Mud Spring which has become very muddy & violent again but with the water level down over a foot; it also appears cyclic.
32949 12 Sep 1971 @ 1500 --- research-mab 09/12/1971- {afternoon temps 2-4pm} - Mud Spring 196° muddy caldron, water thrown 1-3’ in large mound
33243 29 Jun 1969 @ 1200 --- research-mab June 29 1969 - no time - Water dark in main vent, bubbling action with a little overflow to the west. 196ºF water overflow will fluxuate [sic] with action of bubbling.
32987 28 Jun 1968 @ 1200 --- research-mab 06/28/1968 - no time - Chocolate Fountain 203°F
33242 02 Jun 1968 @ 1200 --- research-mab June 2, 1968 - no time - The spring is filled with muddy water with some boiling action.
No attachments for this geyser.
Baseline does not exist.