As we waited for a potential Steamboat eruption, I noticed what appeared to be a vent well to the right of the South Vent, one that steamed heavily at times, especially on Sunday. It's also to the right of the opening Bill Pulliam called the South Vent Drain, whose action was obvious during the splashing of South Vent. I didn't remember seeing anything like that before at that location. The geometry of the formations around the South Vent and the Drain appear to have changed in the last 38 years, so it may just be something that's been exposed by all the erosion over the years.
Back home, a quick review of Paul Strasser's videos from the early 80s didn't show it, either. But the video of the 1991 Oct 02 eruption does show brownish steam coming out with some force to the right of the South Vent. But this could also be an illusion like the way the North Vent also has a "middle vent" during the eruption. This past weekend was my first visit to Norris this century, so I have no idea how long it may have been there, or when it appeared. More info about it would be appreciated.
In any case, during the eruption, as the video shows, there does appear to be water sloshing out of this "far south" or "antartic vent". The video also shows the vent steaming on Saturday. I didn't take much video on during the wait Sunday. Which is unfortunate as later in the day I was thinking that the steaming was heavier that the day before. It would have been nice to compare video on the two days. It's also possible that this vent is an illusion. Where the steam from the South Vent Drain hugs the wall of the crater, so that it appears to be coming from a vent. I believe that might be an example of the "Coanda Effect", which can be observed in the steam that rolls down Beehive's cone.
During the eruption I thought at times I saw the vent slosh up to maybe 25cm or so, appearing much like an eruption of Turtle Geyser during an eruption of Giant. I couldn't find anything like that, however, on the video I took of the water phase. (Maybe it was in the 23 second gap?)
So it may just be some Guru Geyser Gazing, then again maybe this vent needs a closer watch, something I'm not going to be able to do for a while. And maybe someone need to volunteer to see if there is a vent there...
Update : 2018 May 31 I thought the 1991 eruption video was available, but it appears to have been taken down from YouTube at some point. The only link I could find goes to a dead YouTube page that doesn't explain anything.