14 June 2010
Thanks to a number of people for bringing this one to my attention. The community of Oliver in British Columbia yesterday suffered an impressive mud and debris flow that is reported to have destroyed five homes (images from the Vancouver Sun):
The flow has clearly come out of a deeply incised gully in the mountains:
A perspective view of the excellent Google Earth imagery of this area is rather helpful:
Two things to note here (the flow hit the area just above the “97” on the image above). First the community that has been hit by this flow is located on a small fan that has been formed by this type of flow. Second, the very narrow, deeply-incised channel mouth is the classic location for this type pf flow, where a blockage allows debris and water to accumulate, before collapsing to generate a flow. It is interesting to note that this area has reportedly experienced unusually heavy rainfall this spring and early summer.