Thanks to both Beehive and the bear closure, I was slow in getting downbasin for the morning Grand prediction, and so saw the start from north of Crested Pool. But as I walked toward the eruption through the Sawmill Group, I noticed something that hadn't been there when I left last July: a small hole near the point where the Old Tardy and the Crystal Spring runnoff channels combine.
|
|
|
|
Old Tardy's new drain, 2008 May 18
Once the Grand eruption ended, I got the chance to examine it more closely. From the lack of a splash zone, I quickly decided that it was not any sort of explosion feature. The erosion was clean, but was also fairly deep. I assume it was something that broke out a few weeks to several months ago. So I was a bit surprised when Scott Bryan told me that he hadn't noticed it just two days earlier. This implies that the opening was only a few hours old.
The opening is about 15 to 20 cm across, and a nice round shape. From the walkway, it appears to be undercut and layered in a manner similar to those openings that have over the years appeared across the walkway from Scalloped Spring. Early Sunday morning it could be seen steaming gently, but that could have been the result of all the hot water pouring into it. And a lot of hot water poured into it. During the Old Tardy eruptions that I saw, I would estimate well over half, but less than 90% of the water that would have gone into the runoff channel went down the hole instead.
Back in 1990 I sketched out maps of all the features in the Sawmill group, and on the one for the Old Tardy area I noted a couple of areas of steaming ground. One of these developed into the small slit in the runoff into Oval. (Which was spitting nicely during the Penta eruption Sunday morning.) Another one of these corresponds to the area of this new hold. So it's not really new, just that the lid has finally been removed. But unlike other holes in the area, this one has all that water flowing into it.
All that water is going somewhere, and, at least for a while, having a considerable effect on down below. That water has to go somewhere, and as it moves, ti will be causing erosion like that in the gravel on the surface. This could cause further holes to the surface to develop, or break into the plumping system of some of the other features of the area. But most likely I would expect we'll see nothing obvious. Still, it'll be interesting to see what happens next. We know that Slurp is a part of the Sawmill Group, and this drain lies between it and the rest of the group.