Orange warning level at Veslemannen due to rain
NVE increases the danger level to orange for the Mountain area Veslemannen (“the Little Man”) due to heavy rainfall and increased rock movement.
Veslemannen is a small but very active part of the Mountain area Mannen.
The danger level for Veslemannen was raised to the yellow level on June 13th, due to increased rock movements. Since then, the movements have been largely constant.
There has been a fair amount of precipitation on Mannen on Sunday morning. Significant rainfall has been reported until Monday evening. The precipitation will after that, probably be in the form of snow.
Large movements on Veslemannen
Mountain movements are increasing on Sunday, but the sensitivity to rain is uncertain. Earlier in the year, the mountain reacted little to precipitation this early in the year, but the situation is different now, with large movements early in the summer.
The movements are now approximately 15-20 millimetres per day in the upper part and 4-5 mm in the lower part of the mountain section.
At orange danger level, two daily reports are published (morning and evening) on Rockslide warning for Veslemannen
Mannen and Veslemannen
Mannen is an unstable mountain area located on the west side of Romsdalen in Rauma municipality, Møre og Romsdal. Mannen is part of the three-kilometre-long Børa-Mannen complex.
The Børa-Mannen complex became part of the NGU mapping program in the late 1990s. Periodic measurements with GPS between 2006 and 2008 showed that it was moving the most in the unstable mountain area Mannen, and a permanent monitoring system was established. This, currently, consists of GPS antennas, lasers, tension bars, tilt metres, instrumented boreholes, geophones and a ground-based InSAR radar. In addition, there is a weather station and camera.
Movements can be measured between 600 and 1200 meters above sea level. The upper part moves at a speed of approximately 2 mm/year. There is a sudden transition to the parts below, which have a speed of approx. 5 mm/year. In 2014, a very active local party of the Veslemannen was discovered, with annual movements of just over one metre. A geological evaluation of the incident in 2014 is available in the report series of NVE.
A rockslide from Mannen will affect some habitation, E-136 and Raumaabanen. In addition, upstream and downstream floods in case of dam fractures could affect 1,650 inhabitants of Romsdalen. In NGU’s risk classification, Mannen has a high level of danger with medium consequences.
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