First observed eruption on 2021 July 31, and concerted with Sawmill Geyser seen on 2021 August 17, seen from Grand benches.
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Notes and Observations on Geysers in Yellowstone and Elsewhere
First observed eruption on 2021 July 31, and concerted with Sawmill Geyser seen on 2021 August 17, seen from Grand benches.
Some typical behavior, and some unusual behavior of East Sentinel during August and September. Chapter markers for—
I was digging around in my files, looking for something else, and I came across this copy of a letter I sent to a friend two days after Giant Geyser erupted in 1986. Since I wrote it while the memories were fresh, I figure it might be interesting. The photos posted here were taken by George Strasser (Paul's brother), who not only had a camera, but remembered to use it.
On 20 August at 1136, Giant erupted. I was at Daisy for the start, and had just passed Giant five minutes earlier. At that time, it looked like it has all summer, fairly dead. So I get to Daisy, see that Splendid's markers are in place (it had four eruptions the next day), and start to unload my pack. Then I looked over at Daisy, and saw this huge steam cloud rise above the trees.

Paul Strasser, John Railey and I have been using CB radios to keep in touch. They have been useful, but this time they paid for themselves. I grabbed the radio as I was running down the boardwalk and yelled into it, "Paul, something's erupting in the Giant Group!" He had just turned his on, and heard the "erupting in the Giant Group" part from the Lodge Cabins. He and Suzanne were down there in twelve minutes. Several other people saw the steamcloud from the VC, Lower Ham's store, or from Fantail (Biscuit Basin) and assumed either Grand or Oblong. They didn't see it.

[Paul and Suzanne were about to head out with the family of his brother George, "to look for animals", when the call came. The family was abandoned, allowing George to walk out on his own. Fortunately, he took the only series of photos of this eruption that I know about.]
Talked with some people there at the start, and they said that the sputs started maybe 30 seconds before Giant, and Mastiff was erupting only three to four feet high, but overflowing. When it started, Giant sent out a wall of water, running over the south end of the "T" boardwalk. They were afraid of scalded feet.
As I ran around the trees, I could see the water column still climbing. Mastiff was steaming and splashing heavily, while Catfish was sending a thin angled spray to 25 feet. Bijou was steaming only, and the others quickly followed. I took a short cut, and was quite pleased with events.
Giant was now near maximum height, which I estimated [measured?] to be between 150 and 180 feet (~165'). Two night before Sam Martinez and I were going to lay out a baseline, but decided not to since we would never get a chance to use it. [I think I told Sam: "It'll get stolen before we can use it."] The water column was thick, a lot like Ol' Filthy in that sense only. It also pulses, like Beehive, so it doesn't stay at max height, but drops to about 80', then surges back up. The water seemed clear, and the weather was excellent. Clear sky, dead calm but a bit humid. Paul said the steam cloud had to be several thousand feet high. Earlier that day was a thick fog, and later it rained.
By the time Paul and Suzanne arrived, surges were still in the 120' range, but the power had definitely diminished, Originally the water column appeared vertical, now it began to angle to the west slightly. It also sent spray toward the boardwalk. But on the whole, it looked exactly like the old photos.

A half hour later, Giant was still hitting 50', but there was little runoff. By now several sputs were erupting on the platform. They looked like little Uncertains, but only ~4' high. They also surged at the same time as Giant.
By 1227, Giant was mostly steam, and all steam by 1236. Grotto was not erupting all this time.

This was a strange eruption for coincidences. Not just Sam and I at the baseline. The day before at Splendid (no eruptions) T.Scott commented that he didn't have his camera, and if Giant erupted, he would kill himself.
South Purple pool had had several heavy surges of water earlier this year, and now was down below overflow. Later Grotto had some sort of steam phase, or minor eruption. The sputs between it and Rocket were erupting, but Rocket and Grotto made lots of noise and occasionally splashed. The next "real" Grotto [eruption] did not have an eruption of Grotto Fountain [preceding it].
Oblong has been weird this year, with intervals from 32 minutes(!) to 24 hours. Most intervals seem to tend toward 20 hours. Now it had three eruptions in a three hour period, with one interval of 37 minutes. These closing eruptions of a short interval are strange. The water is ejected from an empty pool, and some jets [from the north side] reach the river. They area also very noisy.
It took Bijou about 24 hours to recover, but the next day, the group looked as good, if not better, than it had all year. Now I'm hoping for an interval of less than a year. Say this coming March.
That night, we measured out the distance markers for Giant. Holding one end of the tape over Giant's vent, knowing that it couldn't erupt, was a scary experience.
In the previous thirty years, there had been only four known eruptions of Giant— in 1963, 1978, 1982 and 1984. It's been twenty four years since the last known eruption of Splendid...

Splendid was active then, and the best way to catch a series was to immediately notice when one started. Daisy was erupting nice and regular, about every 75 to 80 minutes (excluding wind effects). The initial eruption of Splendid would take place shortly before Daisy was expected, so if you didn't see an eruption at the predicted time, it was time to make a quick bike ride out to see what was going on. So every hour or so, I'd ride my bike over from The Box to the fence that ran along the walkway west of the Lodge. If I didn't see Daisy after about ten minutes or so, I'd head on down basin.
On 06 Aug 1987, around 10:30, I did my usual ride up, and saw a plume of water over on Geyser Hill. It wasn't Lion, and at first I thought I was seeing a North Goggles major. Then I realized that the water column was to the left of Lion, on the wrong side. I had no idea if it was Big Cub, or Lioness, so I got on my bike and went on around the circle to get a better look at Geyser Hill.
As I approached the Visitor Center, I saw Jim Lenertz and Rick Hutchinson looking over there with binoculars. They too had noticed the activity, and wanted to get a better view and to figure out which geyser it was.
It was Big Cub, and fortunately, Phil Landis, who was working as Rick's assistant, was on Geyser Hill near Teakettle, and was able to take this photo. (I don't know how to contact Phil for explicit permission. But it is, as far as I know, one of the few, if not the only, photo of Big Cub in eruption.) We watched the activity for at least 3-1/2 minutes, and I would estimate the height was from 10 to 12 meters. Note also that Little Cub was also in eruption.
Afterwards, Rick went over to checkout the platform there, to see if there were any other changes (or signs of manipulation). I tagged along. Everything looked normal, and if we hadn't actually seen the eruption, we wouldn't have seen any evidence of an eruption. (Other than it was a bit wetter down wind of Big Cub, but that dried quickly). The one interesting thing is that the vent has a little side hole in it. A small jet of water coming from it can be seen in the photo on the left.
And I did see Daisy a few minutes later, so no Splendid activity that day. Or for the next few weeks. But I did see Giant about a month later.
Update: I've been told that Phil took the photo as part of his official duties working for Rick, so it's in the public domain. And that Phil died of cancer a few years back.
While I walking around Geyser Hill, Giantess made the transition to a weak steam phase.
M.A.Bellingham recently came across a photo in which I am "figure". Here's what I remember of that visit, which, after 35 years, may not be accurate.

Over the winter in 1986, probably in February, a snowcoach driver reported seeing a huge steamcloud off to the west of Norris. By July, someone had visited the area, and reported that there was at least one new, deep crater there, which had uprooted trees in what appeared to be a non-thermal area.
On 31 Jul 1986, Rick Hutchinson went out to investigate, and I tagged along. He parked at the large turnout in Elk Park, southwest of Norris. We forded the river and headed off to the north. The meadow area was pretty dry, so we didn't need to deal with marshy areas. We then we headed through the trees. Rick pointed out at one point that we were passing through a very old sinter shield area. For some old trees that had fallen over, and the white sinter among the roots was obvious.
As we approached the blowout crater, we went along a creek. For about 50 meters (or more), there were a series of frying pans in the bed of the creek. I don't remember if we were headed upstream or down. The blowout was near the creek.
Rick knew what to expect, as part of the gear he had brought out was a rope for rappelling into the crater so he could take samples of the water and soil and rocks. I told him that I didn't know how to help him if he got in trouble, but he said that there shouldn't be any problem. He also brought a small saw, in order to cut one of the tree trunks that had been snapped off and then count the rings, and get an idea of how long it had been since there had been thermal activity there.
So while Rick was down in the crater, I picked a nice sized tree and cut off the section. We counted 75 rings on a tree that had been alive when the eruption happened. I'm not sure what sort of things Rick collected, but he never needed my assistance while down in the pit.
As for a name, at the time I thought that "Sizzling Creek" would be a nice, bland, almost generic name that still was descriptive of a memorable feature of the area.
More of the strangeness that comes over the NPS radio frequencies during August and early September.
Decided that I needed an early morning Grand eruption, so headed out just as it was light enough to not need the headlight. Wasn't foggy like the previous dawn eruption I went out to see, but the walkways were slippery with frost. Waited for three Turban eruption intervals and got a short One Burst Eruption where Vent & Turban didn't quit.
Heard a report of possible Oblong eruption, so went out early to check it out. Shortly after noon I was able to see the empty crater. Also, in the background, I noticed that Solstice was in eruption, the first I've seen it this year. From the Bijou cage, I could see that there were wide runoff channels coming down from it, so it had been erupting for a while. On the way back, on the extreme northernmost part of Oblong's crater I noticed a small jet of water just above the rim.
The Giant Platform seemed to be in a marathon recovery mode, as Bijou was almost off. Every dozen seconds or so a few droplets could be seen coming from it, while the platform itself is as dry as I've seen it. No runoff from Mastiff, no damp spots in the catch basins, and little steam.
Back at Grand, I'd seen a Turban eruption as I tied up my bike. So I was surprised when I saw Turban start about 32 minutes later. Seemed like a Turban Delay Interval. The duration on Turban was well over five minutes, and the next Turban eruption had no overflow from Grand, which tends to confirm my suspicions. But then we got another delay, this one also well over thirty minutes. As the overflow started to look really good, we got a boop out of Grand, followed by over a minute of nothing happening. Then the waves built backup, and then we got a nicely explosive start to a One Burst Grand eruption. The duration was ten minutes and Vent & Turban quit.
Afterwards, went to check out Geyser Hill. Little Squirt had just started, and I wanted to observe the frying pans I'd seen back in May. It was obviously too warm and too soon for there to be any activity. About an hour later, it looked like there might be some steam coming from the main area, but that could have been just wishful thinking. Also on Geyser Hill, caught a weak Depression eruption that mostly had heavy upwelling and strong overflow until it suddenly dropped about 40cm.
Before sunset, the Sawmill Group was in a deep drain. As I was walking up the hill, Sawmill had a "Big Tardy" eruption with a duration of around 25 seconds.
Over at the Grand Group, Sput D was periodic. After about a half hour, that lead to West Triplet erupting, but not followed by Rift. Once the pool of Grand looked good, it took its time while the waves on the pool slowly got stronger. The sun had already set, but there was still enough glow in the sky to nicely illuminate the burst, which quit at 8m10s. It was steamy, and hard to tell at first, but we did get a nice, tall second burst. At around the 45 second mark, Grand didn't go into "Big Sawmill" mode. It went into "Big Tardy" mode. For about 15 seconds the height of the jets were 10 to 12 meters, at most. Then it finally quit, and for the next minute, it appeared there was water in the pool as the jetting from Vent got stronger and stronger. Finally, after about 90 seconds, the pool appeared empty, and Vent quickly died down and ceased entirely.
With no reports on Grand and it being at almost eight hours, made a quick trip out to check on it. Was one of the foggier days for this trip, and I could tell Sawmill was erupting from the runoff, but I couldn't see it. Wasn't until I got to Rift that I found a quiet, empty crater at Grand. So probably erupted as much as two hours earlier.
Was coming out for the next Grand eruption, but first I got to see a less than four minute long Castle minor eruption. No Turban Delay, but did have to wait through several Turban eruption intervals before Grand started. The first burst lasted almost nine minutes, and the pause between the bursts was short. Unlike a number of the recent two burst eruptions, the behavior in Grand's pool was leaving no doubt of a second.
Did a check on East Sentinel, which is unchanged. Still having 19 minute cycles, although the first heavy overflow I saw was not followed by any activity from the South Rim. From there, spent about 45 minutes at Fan & Mortar, and decided that it was in garbage mode and since it was so soon after the previous eruption, I was wasting my time there.
Found that I can get from the cabin to Fan & Mortar in about seven minutes. Only came close to hitting one person who "had their head up their app". (Old Faithful was in eruption. A whole line of people lined up along the fence along the Inn, except one geezer who had to stand in the middle of the trail to get his selfie, and immediately look at himself in the little screen.) Got there with little time to spare. Didn't drop my pack or get out the raincoat, as by this time Upper Mortar was already having large minor eruptions about a minute apart. After the second minor that I saw, Angle vent looked strange, as if it was in a steamphase, while there was no activity from Gold and only moderate from High. After the third huge minor, when all of Mortar was quiet, suddenly Fan's East Vent kicked in, and then all the vents joined in.
This was the third Fan & Mortar eruption in a row that seemed to come with little warning. The prior activity of Fan did not have the intensity of the previous eruptions, since this time Mortar was dominating. But in each case, there was something about the activity that said that this was not a normal event cycle, and that people needed to be informed.
Following that excitement, went out for a sunset Grand eruption. In the Sawmill Group, the water levels were high enough that Slurp was quiet. Belgian and Crystal were way down, about 6cm.
I believe I saw the Delay eruption when I arrived, as it was a long eruption, and the next Turban interval matched the usual behavior -- no overflow. Also, Turban initiated the eruption, which seems to mostly happen only after a Turban Eruption Delay.
That One Burst Grand eruption was also right at sunset, so the water column of Grand was nicely tinted (and not from smoke) as the sun shone through a gap in the clouds. During the wait, West Triplet also had a short, less than seven minute long eruption, which shut down the other sputs for a bit, but they were back to erupting after the Grand eruption.
Wasn't planning to head out in the morning, but just as breakfast was ready to eat, got the call about Beehive's Indicator. Had plenty of time to get out to see the Beehive eruption which was in dead calm conditions. I didn't see the Base Vent do anything during the eruption.
After that, did head out for Grand, a ten minute One Burst Eruption followed by West Triplet erupting.
With nothing much else going on, went out to Lone Star. Arrived at the end of the first minor eruption. Twelve minutes later, another eruption started. About a minute in, the size and power seemed to increase dramatically, and water could be seen coming from the small vents on the left size. Then, after only two and a third minutes, it all quit. It was 26 minutes before the major eruption started, which was an interval of about 3h15m between the major eruptions.
Back at Grand, arrived with Percolator in eruption. This is moderately unusual, and indicative of West Triplet starting soon. But West Triplet didn't start until an hour-and-a-quarter later. During this time there were just a series of non-descript Turban eruptions.
Grand started shortly after West Triplet. The One Burst Eruption lastest 10-1/4 minutes, and there was water in Grand's vent for about twenty seconds before it drained. Then right after the end, Rift started steaming, so we stayed around to watch the water start down the runoff and go under the walkway.
Over at the Sawmill Group, there was a deep drain in progress. Tardy was having a series of single bursts, two or three per minutes, followed by a longer eruption lasting about a minute with a similar pause before the start of the next series of single bursts.
Did get to see Tilt start while waiting for Castle. Castle waited until the sun had set before erupting. We had left maybe a couple of minutes earlier.
Went out to see the midnight One Burst Grand Eruption, which lasted about eleven minutes. As expected, Belgian and Crystal had risen to near normal height, in response to Rift, and were starting to drop again.
If we had gone up to Norris, we would have probably been exiting the Gibbon Canyon when New Crater/Steamboat erupted. I had just arrived at Fan & Mortar, and it was a relief to get the message from Suzanne, knowing we didn't need to worry about Norris for the rest of the trip.
It had rained overnight, and was still mostly overcast. Cool and damp, as it didn't have a chance to get cold overnight.
As it was, I was on the phone with her when suddenly Upper Mortar had a nice rumble. The High and Gold Fan vents were looking good when the call started, and now, moments later, they looked great. I hung up and actually got on the radio to issue a "heads up" call.
The activity looked a lot like the previous eruption, but Angle was not active, and Bottom vent had been splashing when I arrived. Even if it was early in a cycle, people needed to be informed. Over the next ten minutes, the vents only waned a couple of times, then immediately came back strong. Finally, Angle joined in, and by then High was as high as last eruption's preliminary activity. When the Frying Pan finally started, there was little doubt that something was going to happen.
Upper Mortar never really surged until, suddenly, East Vent took off like last time. Unlike last time, the other vents quickly joined in. Unfortunately, the wind, which had been blowing the steam toward the river, shifted and was now toward the benches. So Mortar was clearly visible, but Fan was lost in a mass of steam.
After the eruption, a quick check at East Sentinel showed no real change, other than the one overflow I saw was not followed by any boiling from the South Rim.
The morning Grand was the second observed two burst eruption in a row. It started three Turban intervals after a Turban Delay Interval. There was a definite false pause about 1/2 minute before the end of the first burst, and the whole eruption lasted just over ten minutes.
Later in the day, came out to a Sawmill Group that had relatively high water. Slurp was completely quiet. Penta was splashing slightly, and Belgian and Crystal were both down about 5cm. West Triplet, Percolator and Sput D were also in eruption as I arrived.
The first Turban eruption I saw had an unusual explosive start. Suddenly a thin jet of water was propelled about three meters above the rim, followed by several seconds of quiet before the usual boiling surges began.
Another fifteen minutes after that, Rift started. At that point Grand was full, but stalled out for the next fifteen minutes, giving us another Turban Delay Interval. Fortunately, Grand had its third consecutive observed two burst eruption just two Turban eruption intervals later. At first it was hard to see the pool as Grand paused, then the steam parted with the pool full of churning water. As with this morning, the second burst was short.
Following that, spent some time in a Sawmill Group that still had high water. It had been higher earlier, as the runoff from Spasmodic was still wet. Watched Penta splash around for a while.
Finally, from the bike rack, watch a Bulger major eruption, but no indication of any activity out of Bulger's Hole.
Went out to illuminate a nighttime Grand. It was a One Burst Eruption after Delay that cause the eruption to be two Turban eruption intervals later, and the eruption lasted less than 9-1/4 minutes.
Got out at dawn to find Fan & Mortar didn't erupt overnight. But over the next few hours, I ended up going back and forth between there and Castle because it insisted on looking good enough. Watched Turban and Sawmill start from the bike racks, just in case needed to run back north. When I did head over to Grand, I saw the One Burst Eruption start from Sawmill (and would have recorded it if I had hit the right buttons).
Also did a spot check of East Sentinel, and it looked unchanged.
A windy day, so went up to Daisy at a four-and-a-half hour double interval, and still needed to wait a half-hour. Otherwise everything there seemed normal, with Daisy lasting 3-1/2 minutes.
Mid-day wait for Grand had West Triplet start before Grand. We did get a second burst, one lasting over two minutes
After that, part of afternoon was spent at East Sentinel, where it still looked unchanged from the last few days.
Fan & Mortar didn't do anything after the morning's events until it was time to head to Grand, when it had a weak event. I watched a couple of Turban eruptions from the bikerack again, just in case it picked up, but it didn't.
Over at Grand, both Percolator and Sput D were active. West Triplet was not near overflow. This has been a sign of Rift in the past. After about an hour, West Triplet finally did start, but it was a short duration eruption and Rift stayed quiet.
Grand itself was getting into that weird mode where it had a Turban eruption interval of less than 16 minutes, and where the overflow starts much earlier than usual. Fortunately, there had been no delay, so the interval for the One Burst Grand eruption was about 7-1/4 hours. It was a twelve minute long duration, which helped drain the batteries of several lights.
Spent three more hours at Norris, confirming that nothing much has changed with New Crater/Steamboat. Just as we were about to leave, of course there was a nice minor. We waited another ten, just in case there was a followup, but nothing happened.
We took our time in the parking lot, putting things away and getting organized. I had just backed out of the parking space and was weaving my way among the people waiting for others to leave when we heard a radio call for another good minor. Made the executive decision that there was no way we were circling around and parking and heading back out. Was the right decision, in that after a couple more nice events over the next hour, nothing much happened.
On the way back from doing laundry and grocery restocking in West Yellowstone, decided to stop in at Great Fountain. It appears it started just after we'd passed that spot on the road where it and White Dome are visible, and by the time we arrived at the parking area. Miraculously, there was a parking spot right across from the walkway. So watched the rest of the first series, and the next two. The second was poor, while the third was adequate.
But the most pathetic thing about that eruption that several hours later, I noticed that no one had reported anything about the eruption, so I had to add in our arrival time to GeyserTimes.
A bit later on, went down to check on East Sentinel, which hasn't changed in activity since the major activity earlier in the week. Still cycling every 19 to 20 minutes with all the activity along the North Rim.
Returning from there, I noticed that the Frying Pan was steaming at Fan & Mortar, and there was the appearance of the end of a normal cycle. So I headed off to Grand.
Walked up on another deep drain the the Sawmill Group, with even Slurp quiet. Saw Old Tardy start, and saw Percolator and Sput D erupting. Then Sawmill started.
Twenty minutes after I had passed by Fan & Mortar, Suzanne was doing the same when she saw splashing in the Main Vent. Even though it was a little over two days in the interval, I left Grand because I know Fan & Mortar can have intervals that short, and it's been doing strange things this year. Turns out the Main Vent splashing went on for a long time, and during that time Lower Mortar was showing the first "fuzz ball" activity in several intervals. The Frying Pans and East Vent were also steaming slightly. Bottom Mortar had a series of eruptions, but when the Fan vents started, they didn't look encouraging, and by the time the Frying Pan started, it was obvious that there was not going to be an eruption.