The lower part of the channel has widened and, more importantly, the steep section has moved up channel considerably. Bear in mind that this image is more than 15 hours old now. The best illustration of the way that this is developing is with this sequence of three images, which are taken about a day apart, starting on 29th May on the left and ending with 31st May on the right:
It seems to me that release of the water in the lake is now highly likely in the next few days. The most likely mode of failure looks to be this retrogressive erosion, which could lead to a rapid release event, but the initiation of erosion through downcutting cannot be ruled out. Downstream communities need to be prepared.
I have received no update on the state of flow in the channel - I will post again when some information becomes available.
Where is the water going to ?
ReplyDeleteDaniel
ReplyDeleteYou can get some sense of the scale in the first, biggest picture - see the access track on the right hand side leading to the area where the spoil was dumped at the base of the slope? That track is wide enough to accomodate JCBs/Caterpillar tracked excavators.
Here is an image, back from Jan 04, 2010.
ReplyDeleteThere is a boulder that with shadow appears to be a tetrahedron near the top centre of the second photo which can be used as a common reference point in the photos. In the second photo, the first slump in the channel appears minor compared to the one below it -- which in the third photo has expanded up to the upper slump. If the retrograde erosion holds at this point, the release may remain controlled for some time yet.
ReplyDeleteI'd keep an eye on this spot.
George