Last Known Eruption
229d 18h 25m ago

Latest Eruptions

Eruption DurationInterval
05 Oct 2023 @ 1432 ie10d 23h 26m
24 Sep 2023 @ 150615d 4h 9m
09 Sep 2023 @ 10578d 1h 0m
01 Sep 2023 @ 0957 ie100d 20h 26m
23 May 2023 @ 1331 ie6d 19h 31m
16 May 2023 @ 1800 ie48y 264d 5h 45m
06 Sep 1974 @ 121548d 19h 41m
19 Jul 1974 @ 16345h 36m
19 Jul 1974 @ 1058

Interval Statistics

Interval Count8
Min5h 36m
Max48y 264d 5h 45m
Mean6y 56d 21h 26m
Median13d 1h 47m

Latest Notes

Note IDStart Time (US/Mountain)End Time (US/Mountain)EntrantNote
34581 16 May 2024 @ 1800 --- cb A good ~10' below the high water mark. Chocolate milky color w a vigorous blooping boil that at its height, occationally bloops to maybe 2'.
34526 11 May 2024 @ 1123 --- jkgood Chocolate milk, 6-8” boil
34377 28 Apr 2024 @ 1225 --- DanS Boiling churning grey liquid
34243 19 Apr 2024 @ 1142 --- MAB fairly low down into the more vertical part of the vent pool area - light brown strong steady bubbling boils over a wide area - no larger bursts = high pressure fumarole behind Congress still active
34176 11 Apr 2024 @ 1000 --- JR A bit low, brown, muddy, roiling.
33915 24 Jan 2024 @ 1531 --- JR Strong roil in center, muddy water. Water level still about 2' below overflow.
33830 16 Jan 2024 @ 1500 --- JR Has dropped an additional foot from the last note. Brown opaque water with a decent bubbling in the center.
33771 11 Jan 2024 @ 1200 --- ypcaribou Very full, grey to clear with nice gas activity in the center. (Time random. During day tour.)
33732 02 Jan 2024 @ 1330 --- JR About 1' below the rim, no longer overflowing. A murky greenish brown. Slight bubble in center.
32925 15 Dec 2023 @ 1448 --- Samsara I had heard a report that Congress Pool’s water level was high. When I walked to it, I saw water seeping through the rocks in the outflow, not quite an active stream. The pool is fairly clear a light blue in color.
31694 28 Nov 2023 @ 1300 --- JR Congress pool is no longer a mud pot….It is slightly murky blue-green colored water. A gentle bubbling in the middle. The pool is now approximately 20 feet across. It is filled so high that it is slightly overflowing into the Solfatara area. Gentle runoff channel can be seen going all the way into Colloidal pool. Wildly different from even just 3 weeks ago. I noticed this last week that it was full but it was too steamy to tell the details. It is now very clear and obvious that this feature has changed drastically from what we saw since April this year.
29316 31 Oct 2023 @ 1720 --- MAB Violent and Low - no seeming pattern to the bursting which could reach 1/3 up the crater
29045 22 Oct 2023 @ 1258 --- SantaFe108 Churning muddy water at low pool. Locomotive Spring splashing.
28982 21 Oct 2023 @ 1610 --- JR 4 or more feet below rim. Strong muddy roil. Low even compared to mid summer. Observed constant roil as opposed to cycles.
28884 19 Oct 2023 @ 1412 --- DanS Active muddy boiling and churning
28852 17 Oct 2023 @ 1619 --- MAB Violent chocolate milk color - last Sat the bigger bursts were all dark mud color - these are uniformly light brown
28749 12 Oct 2023 @ 1705 --- JR Water level fluctuations continue. Lower than a lot of this summer but not the lowest. Perhaps 3' below the brim. Strong roiling mud cycles continue every minute.
29196 01 Oct 2023 @ 0905 --- research-mab 10/01 - 0905am: - Congress Pool seems very hot, muddy, roiling cycles are every few minutes/30 seconds. Water level below 3 feet from rim
28449 24 Sep 2023 @ 1446 --- DanS Low, muddy with vigorous variable churning.
29195 23 Sep 2023 @ 1200 --- research-mab 9/23 - no time noted - Congress is very full & vigorously bubbling
28300 17 Sep 2023 @ 1205 --- SantaFe108 Churning muddy water to about ~4 feet every minute or so then calming down to a few inches high.
28153 09 Sep 2023 @ 1050 --- steve Congress Pool is erupting. The background is a steady bubbling/boiling to 2-4 feet but about once a minute it is more forceful to 6-10 feet, perhaps higher.
29193 24 Aug 2023 @ 1200 --- research-mab 8/24 - no time noted - - Congress filling, calm, then aggressive roil
29197 23 Aug 2023 @ 1200 --- research-mab 8/23 - no time noted - Incredible activity out of Congress Pool. High water level and gently boiling turned into a minor (eruption?) that ejected water 3-4 feet through a construction somewhat in the middle. Afterwards, the level was a ft lower – AC
29192 16 Aug 2023 @ 1500 --- research-mab 8/16 300 pm Congress water level 4” below stick, was active but became quiet – no bubbles 3 times/30 seconds
29191 16 Aug 2023 @ 0900 --- research-mab 8/16 9:00 am Stick still at Congress – very active
27620 15 Aug 2023 @ 1543 --- cb pool still looks like thick chocolate milk with a violent roiling, bursting eruption up to ~8-10'. pool is very low in the vent
29190 08 Aug 2023 @ 1200 --- research-mab 8/8 - no time noted - Congress very high
29189 07 Aug 2023 @ 1000 --- research-mab 8/7 1000am Congress has really filled up
29188 06 Aug 2023 @ 1200 --- research-mab 8/6 - no time noted - Congress Pool is full! Seems to be recycling with several seconds of boiling activity followed by a few seconds of relative calm.
29187 04 Aug 2023 @ 1200 --- research-mab 8/4/2023 - no time noted - Unusual behavior out of Congress Pool. Short moments of aggressive boiling that shoots water a couple of feet high. May have a constriction?
27364 31 Jul 2023 @ 1028 --- MAB ugly violent low
27342 30 Jul 2023 @ 0657 --- ypcaribou Almost empty pool with gray, muddy water violently splashing from low in pool.
27183 23 Jul 2023 @ 1743 --- mhreed Diarrhea mode still engaged. Water level below the branch but having occasional bursts to mid-crater height.
29199 14 Jul 2023 @ 1200 --- research-mab 7/14 - no time noted - Congress was very extremely low!
29198 13 Jul 2023 @ 1040 --- research-mab 7/13 - Congress water level extremely low ~ 1040 am AC
27009 11 Jul 2023 @ 1710 --- cb Congress' pool has dramatically dropped. Its water level is a few feet above the vent. It is chocolatey muddy brown color and erupting with aggressive 🤔churning, roiling bursts that splash to 5+ feet.
29200 09 Jul 2023 @ 1200 --- research-mab 7/9 - no time noted - Congress pool very low
26869 06 Jul 2023 @ 1905 06 Jul 2023 @ 1913 nails Gray water boiling in low pool. Calms down about once per minute, then splashes back up 2 to 4 feet..
26840 04 Jul 2023 @ 1430 --- MAB lower with steady violent wide chocolate color boil
29201 24 Jun 2023 @ 1000 --- research-mab 6/24 1000-1100 rove - Congress Pool returning to a more normal water level but still roiling mud.
26615 23 Jun 2023 @ 1125 --- cb pool is still a muddy chocolate brown, violently roiling boil ~4'. Not spiking to 15'+ like observed in the early spring.
28948 16 Jun 2023 @ 1000 --- research-mab (no time given } 6/16 Congress pool still very active, no rest in sight.
28734 11 Jun 2023 @ 1200 --- research-mab 6/11 - no specific time Congress Pool low but still aggressive mudpot
25924 30 May 2023 @ 1120 --- MAB still violent near perpetual dark muddy splashing - some more voluminous and sustained - base water level may be lower than my previous visit - will compare photos
25876 28 May 2023 @ 2138 --- SantaFe108 Low and furiously surging muddy water with occasional larger burst. Steam making flashlight hard to use.
25651 21 May 2023 @ 1035 --- SantaFe108 Still low with constant surging of muddy water, occasional big burst as well.
25517 18 May 2023 @ 1139 --- mhreed Low water level. Muddy with a constant, violent roil. Occasional bursts to height of crater rim.
28731 04 May 2023 @ 1300 --- research-mab Congress Pool is currently a violent mudpot. Rising and lowering water level, shooting mud 5 feet or so [no specific time]
25044 27 Feb 2023 @ 1336 --- MAB blue green slightly murky but pretty - occasional ping pong bubbles
24504 28 Oct 2022 @ 1600 --- MAB Low - green but not too murky with a few small bubbles
24197 03 Oct 2022 @ 0927 --- WillBoekel pool is low and a murky green
29105 27 Sep 2022 @ 1200 --- research-mab 9/27/2022 - no time noted - Congress looks low and blue
24067 23 Sep 2022 @ 0945 --- CrisG water level approx 1.5 ft from high water mark. water a milky teal color. quarter to half dollar sized bubbling.
24068 23 Sep 2022 @ 0945 --- CrisG water level approx 1.5 ft from high water mark. water a milky teal color. quarter to half dollar sized bubbling.
29104 18 Sep 2022 @ 1200 --- research-mab 9/18/2022 - no time noted - Congress was low and clear
23565 04 Sep 2022 @ 1330 --- cb pool is a murky seafoam green color, dime/half dollar sized bubbles breaking the surface ~ in the center. Water level is difficult to describe, ~1.5' below high water mark.
29103 04 Sep 2022 @ 1200 --- research-mab 9/04 /2022 - no time noted - Congress is low and not so murky
29102 25 Aug 2022 @ 1200 --- research-mab 8/25/2022 - no time noted - -Congress Pool getting murky again
23369 23 Aug 2022 @ 1830 --- MAB watery green - small bubbles in 2 spots
29111 20 Aug 2022 @ 1200 --- research-mab 8/20/2022 - no time noted - Congress is blue!
29090 13 Aug 2022 @ 1200 --- research-mab 8/13 - no time noted - Congress Pool blue & milky
23057 05 Aug 2022 @ 1331 --- cb pool is higher than last observation by ~1'. It is a silty light brown/green color with just a few bubbles breaking the surface. mostly calm pool.
22858 26 Jul 2022 @ 1212 --- cb pool is down another 1' from last note. down 3' from the high water mark along the edge. 2 vigorous boiling points and color is milk chocolate
22663 17 Jul 2022 @ 1457 --- MAB 2ft below top of cracked mud - dirty brown color w 5pt boil- heaviest boils on NW
29077 08 Jul 2022 @ 1200 --- research-mab - no time noted - 7/8/22/2022 – Congress Pool and Scummy low water levels
22399 08 Jul 2022 @ 1142 --- cb Pool down another 6", 2' below high water ring. It's milk chocolate color with a roil boil in the center and on the end by the bw
22270 01 Jul 2022 @ 1337 --- MAB 2 pt boil light brown in color - 1ft below cracked mud
22245 30 Jun 2022 @ 1214 --- cb A tad more of a boil than last observation. 2 main roiling boils in front of the lg rock in the centerish area of the pool. roiling boil to 3".
22164 27 Jun 2022 @ 1214 --- MAB steady boil mud puddle brown
22121 25 Jun 2022 @ 1249 --- cb Pool is a latte light brown color, water is still high and it has 2 roiling boiling areas in the center of the pool.
22079 23 Jun 2022 @ 1548 --- cb CHANGED again!! last time I looked at Congress it was turquoise blue! Now it is a .... ranger green color, kinda gray green & murky! Has a moderate boil & pool is down ~10" from last observation
22075 15 Jun 2022 @ 1507 --- cb Change! The pool is a BEAUTIFUL turquoise blue color, clear with a 2 point bubbler (smaller than a boil) sending out small convection waves. water level is about 3' below the rim.
29067 04 Jun 2022 @ 1200 --- research-mab 6/4/2022 - no time noted - - Congress looking very blue instead of previous muddy/dark
21707 03 Jun 2022 @ 1200 --- MAB color changed from my last view - more of a greenish blue and not mud puddle brown - fairly quiet
21482 25 May 2022 @ 0755 --- TSBryan very low, slight bubbling, slate gray water
21445 23 May 2022 @ 1250 --- MAB stronger boil in several spots than last week and light mud puddle color water looks lower - will compare photos and edit
21243 11 May 2022 @ 1240 --- MAB watery brown - not much boil
21028 18 Apr 2022 @ 1252 --- MAB low - sizzly bubbles - light brown
20339 07 Nov 2021 @ 1630 --- mwolf clear, blue, high, calm, zero bubbles
20193 29 Oct 2021 @ 1711 --- MAB CLEAR blue green- can even see into the vent - water level is above that bottom level of deeply cracked mud
20074 21 Oct 2021 @ 1412 --- mwolf clear, green, calm, with occasional little bubbles
20045 19 Oct 2021 @ 1244 --- cb weird. Pool is a clear, greenish color much like Colloidal Spring. Hardly any boil just a random golf ball sized bubble that slowly makes it way to the surface and pops. Water level is about 6" below high water/mud line.
19923 06 Oct 2021 @ 1602 --- cb pool is greenish brown, low water level and 2 very small bubblers
19832 01 Oct 2021 @ 1750 --- MAB Low but NO boil - pool was in shadow but looked greenish brown
19231 01 Sep 2021 @ 1603 01 Sep 2021 @ 1613 MAB separate VRs of varying water level - one said it was rising the other dropping - gave it 10 min and didn't aee anything other than variation from the heavy brown boil
19114 27 Aug 2021 @ 1844 --- MAB brown water w strong boil o west end
18884 10 Aug 2021 @ 1010 --- cb pool is much higher than I last observed. I find this feature so hard to describe pool level. Pool is 1.5' below the edge of the cracked/caked muddy rim.
18443 14 Jul 2021 @ 1900 --- MAB LOWer still - well below the cracked mud at the bottom of the pit - strong boil with more intense action on the west edge
18274 05 Jul 2021 @ 1555 --- cb Pool is very low. 4-5' below the gray muddy high water mark. Below the gray water mark is 4" of a tan water mark. it has a vigorous 1' boil on the edge closest to the boardwalk.
18089 25 Jun 2021 @ 1125 --- MAB Low w/ 4ft of cracked mud exposed - center boil plus very strong boil on West side
17452 04 Jun 2021 @ 1834 --- MAB Water obviously dropped recently exposing 1.5 ft of cracked mud edges- dropped low enough to have a faint heart shape- color of wet cement brownish gray
17282 30 May 2021 @ 1453 --- cb pool is higher than I've seen. Up to the smooth rim, boil on the north edge and in the center, color of milk chocolate
17067 12 May 2021 @ 1817 --- MAB vigorous boil - mud puddle colored
17033 09 May 2021 @ 1316 --- bbev vigorous 3 point boil in low, muddy pool.
16940 28 Apr 2021 @ 1840 --- MAB Low mud-colored water w a 3 point boil
16352 06 Oct 2020 @ 1511 --- cb Water level has come up ~6" since my last observation. It is still the color of milk chocolate with dark chocolate swirls and has a VIGOROUS roiling boil erupting to 1'+ on the edge of the pool closest to the boardwalk. Diameter of the boil is ~1'.
16212 20 Sep 2020 @ 1714 --- cb I find describing water levels in Congress challenging! The pool is LOW. 2' Below it's high water/mud mark from earlier this summer. It has a vigorous roiling boil on the west end of the pool. It's the color of milk chocolate with dark chocolate swirls on the south end of the pool and has a putrid odor! There are 2 interesting features in the Solfatara area about 30' to the west of Congress pool. 2 areas of boiling springs/liquidy mud pots, each about a foot in diameter and about a foot apart, that are pinkish/orange in color.
15790 29 Aug 2020 @ 1020 --- cb Pool is up about a foot from last observation.
15556 13 Aug 2020 @ 1230 --- cb Wowza! Congress pool's water level has really dropped! Not sure how to describe it other than it is lapping at the bottom of the clayish features on the SE edge of the pool. water level is below the muddy line on the western edge of the pool and has 4" of exposed yellowish color on the edges above the water line. Color is still milk chocolate with dark chocolate swirls on the east edge. vigorous boil on the west end.
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