[Geysers] Giant, Aug. 19 DETAILS

[Tara Cross]

A message from Tara Cross <fanandmortar at hotmail.com>

The first radio call I heard upon arrival in the Upper Geyser Basin was a hot period update from Lynn Stephens.  Great, what a way to start the weekend--I'm stuck in an elk jam just north of Biscuit Basin while Giant erupts.  Once I got out of the jam, I was stuck behind an RV giong 25 mph, but before I got desperate enough to pass, the hot period ended.  Whew.  Even though the hot period was over, I biked down to Giant to see the aftermath and find out what was happening.  After the long string of mini-marathons, Grotto had not marathoned since the eruption that ended in the early hours of August 17.  When I arrived at Giant and talked with gazers, I was told that there were "weird" things going on in the Giant-Grotto area all day long.  Because I was not there to see it myself, I'm going to include a portion of Scott Bryan's Aug. 18 geyser report:

"Today was a weird day for Grotto. South Grotto Fountain was erupting all morning, playing about every 8 to 10 minutes for 2 minutes or so. Typically, this happened between Indicator Spring fills, which mostly were accompanied by _little_ action in Grotto Fountain (at some fills, G.F. didn't even overflow). Finally came an Indicator fill in which Grotto Fountain began boiling up 1 to 2 feet. Then South Grotto Fountain began to erupt again, but this time it was with Indicator high and Grotto Fountain still acting like it was going to erupt. Then the Central Vents began erupting, strongly. Then Grotto started, slowly. Then Grotto Fountain and Indicator dropped, and then Grotto grew strong. I called the Grotto start as 1148 (14 minutes before the strong Giant hot period). Note that Grotto Fountain did not erupt -- if you're going to call this anything, then it was a South Grotto Fountain-Central Vent start. As we say, weird is good."

As an aside, this behavior had many similarities to what was seen prior to the July 3 Giant eruption.  In that case the South Grotto Fountain eruptions persisted for at least 8 1/2 hours, culminating in an actual eruption of Grotto Fountain and then Grotto.  And of course on July 3, Giant erupted after the first Grotto following this behavior; on August 19, it erupted after the third Grotto.  But I digress.

As for the activity at Giant, the following is also excerpted from Scott's Aug. 18 report.

"0759 -- d = 8m 25s, moderately strong. There was a lot of steam (the boardwalks were still frosty in shaded areas), but Mastiff briefly surged up to 4 or 5 feet.
0907 -- very weak, d < 2 minutes.
~1005 -- bathtub.
1100 -- weak, d = 2m 26s.
1202 -- had us all a bit excited, d = 8m 20s. This one did not start real fast, but when Feather Satellite came on things picked up quite a bit. Mastiff was up and down and never more than maybe 3 feet high, but there was a lot of strong vertical surging in Giant, Cave erupted steadily to 2+ feet and etc. There was a pretty good restart at 1213, d ~ 3 1/2 minutes, accompanied by continuing surging in Giant."

K.C. Thomson helped fill in the hot period activity for the afternoon:

1308 -- no details
1530 -- d=5m50s.
1634 -- d=2m15s.

Grotto Fountain began normally at 1602, with Grotto at 1613.  Grotto quit at 1754 for a duration of 1h41m.  The next hot period was at 1829--the one that was in progress while I cursed at the elk jam.  It lasted 7m45s and India was abuot 50% covered.  Mastiff did not do a lot of large surging, but it did reach 3-4 feet at one point (based on Lynn's radio calls).  Cave bubbled to abuot 3 inches.  One thing that was odd about the hot period was that Bijou came on while Mastiff was still overflowing.  Based on what I was hearing over the radio, Bijou splashed a few times, then stopped, then started again more seriously, before Mastiff dropped.  However, Feather quit promptly after that.  There was a Feather restart with a few vertical surges that sent water to the top of the cone, but the surging quickly became angled and never got anyone excited.  (Thank you to Lynn, Kendall Madsen, the Thomsons, the Slivkas, and Rocco Paperiello for all the information.)

The final hot period before dark took place at 2009, and it was so exciting that somebody asked, "Was that even a hot period??"  Feather's duration was all of 1m05s, with the Southwest Vents starting 28 seconds before Feather.  No other vents participated, and Mastiff did not overflow.

Since the sun was setting, some gazers decided to call it quits for the day and I headed in as well, knowing that if I was going to stay any length of time at Giant I needed an actual meal and not just the granola bars I had tossed into my pack.  Oblong was called at 2118ns.  I was still eating when Kitt called the next hot period, which started at 2133.  I made a dash towards Giant, but didn't get very far, as the hot period lasted just 2m.  Feather Satellite came on, but once again Mastiff did not overflow.

I was glad for some breathing room so that I could get prepared to wait at Giant into the night.  It was already getting chilly, so I put on all of my winter layers.  I planned to stay at Giant until the next decent hot period--not so much because I was optimistic about Giant, but because I was curious.  The reports of weird goings-on at Giant had be intrigued, and I didn't feel comfortable leaving Giant unattended until I had seen a relatively strong hot period.

Grotto started at 2156ns, and the next Giant hot period was at 2243.  While this one lasted lnoger than the others (5m10s), it expended almost no energy.  Mastiff only overflowed lightly, and the only vents to participate were Feather and the Southwest Vents, which had once again started prior to Feather.  After this, a few more gazers headed in for the night, leaving myself, Kitt Barger, and Tom and Oriana Magnera at Giant.

Kitt had her timing down--she waited about a minute for a huge Rocket major at 2340.  On her way from the Grotto area back to Giant, Kitt noticed that the water level in the GIP was about 4 inches below overflow, but by the time she got back to Giant, Mastiff had dropped out of sight.  We surmised that this was a bathtub or footbath at 2345.

At 0010, I got a call on my phone.  It was Suzanne Strasser, who was just arriving at Old Faithful, just 8 hours 26 minutes after leaving Westminster (the trip normally takes them 9 1/2 hours).  I was happy to tell Suzanne that she was safe for the time being due to the bathtub, and that Grotto had just shut off at approximately 0005 for a duration of ~2h10m.  Paul, Suzanne, and Linda hastily unloaded their car, grabbed layers and flashlights, and headed for Giant.

Wanting to save batteries for the hot period, Kitt and I relied on sounds coming from the Giant platform to know what was going on.  As we sat in the darkness, we heard interesting sounds from Bijou.  It had not paused since the bathtub, and was on so strong that we could hear steam mixed with the water.  This persisted until 0045, when Bijou had its first pause.  We looked for water in Mastiff, but Bijou restarted right away.

It had been getting colder and colder, and finally Tom and Oriana decided to head back to their car to warm up.  Linda and Suzanne arrived at Giant in time for the next pause at 0056, but once again we did not see water in Mastiff.  Then at 0107, I noticed that Bijou had stopped again.  As I stood on the railing looking for water in Mastiff, I glanced towards Oblong and saw Paul's light approaching on the boardwalk.

I turned back to Mastiff and the water was quickly rising.  The Southwest Vents were sputtering, and then in full eruption at 0108.  Feather began to overflow, and started at 0110, about 90 seconds after the Southwest Vents.  For nearly 3 minutes, I was worried that this was yet another weak hot period, not even strong enough to allow me to leave Giant for a few hours to get some sleep.  Only Feather and the Southwest Vents were erupting, and Mastiff was seeping a trickle of overflow.  Then, around the 3-minute mark, Mastiff started to push out small waves of overflow, though it remained flat.  Then we noticed that Cave was bubbling to 3-4 inches.

Then someone said they thought Mastiff was dropping.  But Linda said, "No, it's still there--there's more runoff now."  Then, in a matter of seconds, the pace of the hot period picked up.  Feather Satellite came on near the 4-minute mark, and soon Mastiff was boiling steadily.  A dramatic increase in overflow began to envelop the platform with steam, so Paul ran back towards the GIP to get a better flashlight angle.  I saw that Cave was now boiling vigorously to 6-8 inches.  Paul's light revealed that Mastiff's boiling was getting stronger--1, 2, then 3 feet and getting wider.  The runoff got noisy as it poured off the platform.  The next time I looked at Cave it was erupting, first to 2-3 feet, then a full 4 feet in a steady column.  We could hear Mastiff continuing to surge, and I saw water to 5 feet at one point.

My initial reaction to all of this was, WHUH????  It was like I was suddenly watching a completely different hot period.  Just a few minutes before, I was afraid that I wouldn't even feel safe leaving Giant for more than an hour or two; now, we were starting to get excited, and Kitt was digging through her pack for her poncho.  I would have found her optimism less understandable if Cave hadn't been erupting higher than I'd ever seen it--it looked like a slightly smaller version of Feather.  But I was still incredulous.  Aside from Cave's activity, I'd seen hot periods like this before, and Giant hadn't erupted on any of them.

"How's India?" I asked as Mastiff's surging returned to 1-2 feet.  Suzanne called back that India was covered.  About then Giant caught our attention with nice water to halfway up the cone.  It was about 7-8 minutes into the hot period, and the platform was so steamy that it was sometimes hard to tell what was going on.  Mastiff appeared to go flat, but I couldn't tell if it was dropping.  Paul, still at his vantage point on the main boardwalk, called out that he thought Mastiff had dropped.  Then Bijou came on strong, and there were huge bursts from Catfish--10-15 feet high.  I was starting to believe, but I still expected Feather to be weakening when I pointed my flashlight in that direction.

Instead, through a veil of steam, it seemed to be getting stronger.  Yes, now it was the height of the cone, with the Satellite erupting furiously next to it.  Now I realized that I was in trouble.  I had learned from the July 30 nighttime Giant eruption that in the cool and almost windless night, it's impossible to stay dry.  As the vertical surging began in Giant, Suzanne and I frantically tried to cover ourselves and our packs with ponchos, hearing Kitt and Linda screaming with each surge.  Tom and Oriana had turned around when I started calling the hot period and were now at Giant, helping us cheer it on.  By the time I got my head back out of the poncho again, the surges were over halfway up the cone and dumping water out the front.  "It's gonna GO!!!" Kitt squealed, and there was a general stampede out of the monkey cage and back to the main boardwalk.  In what seemed like a matter of seconds, the surging was reaching the top of the cone, then over the top.  Two fat surges completely filled the cone, and then Giant burst up to 30 feet.

GIANT, 0121!!!!!

Our flashlight beams followed the column up and up and up, and for a few moments we could see the top spikes glittering against the starry sky before huge droplets came cascading back down, enveloping the cage and landing beyond the main boardwalk at the junction of the "T."  Then came the wall of steam, and then the rain.  I was very happy that I had decided to try out my new waterproof boots that night, as being anywhere in the vicinity of Giant meant standing in a steady downpour.  It was even worse when I returned to the cage to feel the power of Giant at close range--in fact, it was so wet there for most of the eruption that I could only stay for a few minutes at a time.  Still, it was well worth standing closer to Giant as the water and steam roared out of its cone and Bijou roared alongside.  Mastiff joined in with steamy bursts of water to 5 feet above its crater rim for a few minutes.

We admired Giant from various angles, but after about 30 minutes we started to notice that the water on the boardwalk was turning to slush under our feet.  Eventually Linda, Tom, and Oriana decided that in the interest of avoiding hypothermia, they should probably head in and get warmed up.  They discovered that the boardwalk was a sheet of ice, so decided to return via the bike path.  Eventually, we could see the crescent moon rising over the hill behind Giant, and soon it was backlit in the pale moonilght as it waned to its final bursts.  The duration was 101 minutes.

Hey, weird is good, right?

--Tara Cross
fanandmortar at hotmail.com
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