"Waiting for the Splendid" is something that neither I nor anyone else has done this century. While that sput up at Norris may be known for having intervals "from four days to fifty years", Splendid has had intervals from one hour to 25 years, a much larger range. And, unfortunately, it appears that the current 25 year interval is going to get longer.
What does one look for while waiting for Splendid, and what was it like?
Observations of Splendid's activity must be done from the northern walkway. The pool can't be seen from the southern. The only advantage the southern walkway has is that the Giant Platform is visible and any activity over there can be seen.
There are two runoff channels toward the north that pass under the boardwalk. Both would have a trickle of water coming out Splendid's pool. The western one was where Marie Wolf place her marker. Originally a pinecone, it became a stick once the pinecone disappeared. The stick was about 25cm long, and normally would be moved several meters down the runoff during an eruption. But on several occasions, it too would disappear, and need to be replaced.
There was a band of sputs between Comet and Splendid. At least two of them were within the crater itself, one along the wall, the other nearer to the vent. Their activity was only noticeable when the crater was drained. Over by Comet there was at least one good sized sput between the cone and the walkway. Many of these sputs are no longer visible, and the remaining activity seems to be decreased. No variations were ever noted in relation to Splendid and Daisy's eruption cycles. And except after concerted eruptions, Comet didn't show much variation in its activity either.
If those side vent sputs to the west of Splendid's crater ever got a name, I don't remember Marie Wolf ever using it. And they have never varied in activity either.
Activity for Daisy when Splendid wasn't active was fairly consistent. We joked that 3m43s was normal, and that any variation of more than a few seconds was noteworthy. The same held for intervals. Daisy intervals were around 80 to 85 minutes long. As short as 75 wouldn't be considered unusual, and over 90 could happen if it was windy. But consistent variation in interval could indicate that Splendid was perhaps preparing to erupt, especially if the barometer was dropping.
As Daisy erupted, the activity from Splendid calmed down, and the water level dropped. By the end of the eruption of Daisy, Splendid would be down about 30cm or so, and calm. Over the next few minutes, it might have an upwelling of water, but no boiling or bursting. After about five minutes, there would then be a large surge from the vent, as high as a meter, and the crater would quickly fill. Soon Splendid would be back into overflowing down those two runoff channels. As the next Daisy eruption approached, Splendid would drop slightly.
Splendid erupts in series. While some series could consist of a single eruption, it was more common to have about half a dozen eruptions over the next few hours. Some series could last as long as 36 hours.
When Splendid was in an active series, the activity of Daisy could change. Intervals could be as long as seven hours. Some of the solo eruptions during a series could be as short as two minutes, and short and weak, big minors. Or they could last up to five minutes and be quite powerful and tall, which was typical for the solo after a long interval.
There were two windows in which Splendid would erupt to start a series. The first one was about ten minutes after the start of an eruption of Daisy. This was a common time for a big surge as Splendid refilled, and it wasn't usual for there to be a false start during that time. And false starts could build into actual eruptions. Most of these initial eruptions immediately after Daisy lasted about two minutes, and were not known to be particularly tall.
The second window was about ten minutes prior to an eruption of Daisy. If you considered the average interval to be 80 minutes, then this meant that there could be an eruption about 70 minutes after a Daisy eruption. These tended to be stronger eruptions, with durations from three to five minutes.
After the initial eruption, both Splendid and Daisy would quickly refill and become even more vigorous in their activity. A second Splendid eruption could follow within 60 to 90 minutes, or sometimes take several hours.
When the interval was shorter, and the initial Splendid eruption was prior to the expected time for Daisy's eruption, this could result in a concerted eruption. Later in the series, a short interval cold also result in a concerted. Concerted eruptions did not follow a solo Daisy eruption. They seemed to need a solo Splendid to precede them.
Many of the Splendid eruptions came in pairs, the first eruption being about four minutes long, then about an hour later followed by a longer, stronger eruption that usually was in concert with Daisy.
A concerted eruption almost always started with an eruption of Splendid, with Daisy joining in after a minute or so. Daisy could be huge, with a long duration, or it could be weak. In the 1980s, it seemed that the strong eruptions would stimulate Splendid into a strong eruption also. That wasn't the case in during the 1997 activity. Then, when Daisy started, Splendid would weaken, and often quickly finish erupting. There were proportionally a lot more concerted eruptions that year, but they weren't as good.
A strong concerted would cause the entire system to drain, including Comet. No water would be visible in any vent. As it refilled, Brilliant pool would erupt sideways across its pool. A concerted eruption also usually meant that it would be four to six hours before the next eruption in the group, and that eruption was often a solo Daisy. Splendid's intervals would be more in the eight to ten hour range, although I remember getting caught by unexpected intervals in the four hour range.
In the summers of 1986 and 1987, Splendid eruption series did tend to start during low barometric pressure. I kept a barograph running and when the line started dropping, we paid closer attention to the Daisy Group. It seemed like the series usually started when the pressure started to rise back up, even temporarily before a deeper drop. So it wasn't unusual for the series to start in rotten weather, and end up when it was nice.
On the other hand, more than once I spent all my time out there waiting in rain gear. Sometimes we'd wait out at night if it cleared up. But those were cold nights. Once fell asleep in a down bag on the walkway and when awakened a few hours later by some gazers, I had to crack the ice off the bag. The temperature was 16°F. (Because it was a long quiet period, when Splendid did erupt, it had one of the more spectacular concerted eruptions to end the series.)
Splendid has two centers of activity down in its vent-- the "Side Boiler" and the "Main Vent". The Side Boiler is not to be confused with the sputs on the other side of the bridge. It was over the Side Boiler where Marie Wolf once got a temperature of 217°F using a maximum thermometer at the surface.
When Splendid is active, both of these vents can boil up in a full pool to heights of at least a meter. The Main Vent is wider and behind the Side Boiler as seen from the walkway. The Side Boiler activity was considered to be a bad sign, in that its activity never built up into an actual eruption, or even a false start.
An eruption of Splendid starts with the activity of the Main Vent climbing higher than the usual one meter boils. It can slowly build, and at some point the boiling turns into more of a weak jetting. At the same time, the water starts pouring out of Splendid's crater and down the runoff.
The jetting can reach as high as five or six meters, then, about 20 to 30 seconds after the start, it will suddenly stop. This is a "false start", and they were quite common during the 1980s active series. Or the activity would start to climb, slowly over the next half-minute or so to reach the maximum height. In either case, the start of the eruption or false start was the time when the jetting started.
An eruption of Splendid is probably the least noisy of any large geyser. At times, most of the noise comes from the water landing around the vent. Toward the end of a strong eruption that lasts over six minutes, Splendid can start to turn to steam, and get noisier. I never saw them, but in the late 1970s there were eruptions where it had a definite, noisy steamphase that could be heard over by Grand or even farther away.
Currently the activity in the group shows no sign of any shift toward Splendid becoming active. (Yes, it's always possible for a single isolated eruption to occur, especially in response to an earthquake.) The cycle of Splendid responding to Daisy is still there, but muted and not approaching the levels shown in those years.
What's primarily needed, I believe, is for there to be overflow from Splendid, especially as the time of a Daisy eruption approaches. Daisy's intervals need to get shorter, back to under 100 minutes, and Daisy's durations need to be about 20 to 30 seconds longer.
Even when not in an active mode there would be isolated eruptions of Splendid, as was the case during between the activity that died down in 1987 and picked back up in 1996. Many of these solo eruptions were the type right after Daisy erupted, and during springtime. There were at least two Memorial Day weekends where I was in the crowd at Grand and we got to see Splendid, too.
In 1997 there was so much going on, with eruptions of Giant, Fan & Mortar, and Splendid, and Grand still being interesting, that I had to prioritize my attention. I never saw Fan & Mortar erupt that year. The last five burst Grand I've seen was from Splendid, about an hour after an eruption, during the 1997 activity. (Mike Keller was there, too.) As it turned out, I was one of the few to concentrate on seeing Splendid, and if my count was accurate, I saw one hundred eruptions that year. Splendid hasn't been seen since, so I made the right decision.