Read an article the other week from Scientific American on Looming Landslide Stokes Fears, … about the Rattlesnake Ridge landslide that’s taking place in Washington State in the US. Apparently there’s a fissure that has been slowly widening and is -slowly causing a landslide in the area.
Of course, recently there’s been significant mudslides in Montecito near Las Angeles, that have resulted in a number of deaths and destruction of many millions of dollars of property. Now mudslides and landslides are not exactly the same but my guess is by improving our understanding of landslides may also help us better understand mudslides and hopefully, provide a better way to predict the dangers inherent in both. Ditto for snow avalanches.
Science to the rescue
Geologist and geomorphologists from Washington State and the USGS have been instrumenting Rattlesnake Ridge with over 70 GPS sensors. They are also following the landslide using LIDAR snapshots to map terrain movement to try to better understand that movement over time.
It appears that Rattlesnake Ridge is moving about 1.6 ft/week. There’s a small community at the bottom of the ridge, and in the event of a complete collapse, knowing where and when to evacuate can save lives.
The belief is that the landslide at Rattlesnake Ridge and elsewhere are the result of an interaction of subsurface materials that holds ground in place and surface material moving down the a mountain side. It is the interface between these two layers that determines the rapidity of the landslide and its direction.
Land/snow/mud slides occur all the time
There’s a website called the Watchers that records significant landslides around the world. Aside from Rattlesnake Ridge and Montecito, they list a significant snow avalanche in South East France that cut off a village of 151 people, floods and landslides in the Philippines resulting from hurricane Kai-Tak that killed 26 people, a massive mudslide in Southern Chile which left 3 dead, 15 missing, and a new lake forming in India after the Gangotri glacier collapsed that rerouted a river flowing from the glacier melt, all of which occurred during December 2017.
Snow avalanches, mudslides, landslides, etc. are all similar activities involving matter moving down a mountainside. The extent, direction and rapidity of its movement, all depend on the surface topology and subsurface and surface materials present in an area.
Knowing when to call an evacuation of the area immediately in a destructive path of a land/mud/snow slide and knowing where that destructive path is going to be is what the team at Rattlesnake Ridge are trying to help find out.
Photo Credit(s): 2104[sic] Washington Landslide by USGS