Rock Fall in the Swiss Alps

September 02, 2019

RoseR_rock_fall-base-XL

RoseR_confluence-XL

Photographer: Rose Riemer 
Summary Author: Rose Riemer 

While hiking near Kandersteg, Switzerland (Oeschenensee region) earlier this summer, I observed the rockfall shown above. Rocks were tumbling down the beds made by small snowmelt streams (top photo). We could hear rocks falling during much of our hike and occasionally could see dust from the rocks disintegrating as they fell. The bottom photo, at the confluence of two streams, shows the upper stream (at center) filled with mud and rocks; whereas the lower stream (white water along the bottom of the photo) is relatively clean.

It’s worth noting that in late June much of Europe experienced a major heatwave; record temperatures were recorded at 30 locations in Switzerland (both low and high altitude sites). Rapidly melting ice and snow at higher elevations, from the high temperatures and also from heavy downpours of rain, dislodged pebbles as well as small rocks, cascading them down the mountainside. Photos taken on July 6, 2019.

Photo Details: Top - Camera: NIKON D750; Exposure Time: 0.0013s (1/800); ISO equivalent: 2500; Focal Length: 210.0mm; Bottom - same except: ISO equivalent: 7200; Focal Length: 62.0mm.