The growing and shrinking of mountains – the story of the height measurement of the Mönch
Cartographica Helvetica 16 (1997) 3–12
In 1996 quite a stir was caused by a press release proclaiming Mönch, a mountain in the Bernese Oberland, has grown by eight meters during the last seven years (which is the revision cycle of the topographic map series 1:25,000). A meticulous study was launched to document the height measurements made during the last 250 years. In 1754 and in 1788 the first attempts to measure its height were made with the method of triangulation. In the following years, the surveyors moved ever closer to remeasure the mountain. It was not until the introduction of aerial photography that the height of Mönch could be determined more accurately. Probably the most accurate measurements were carried out in 1957 in the scope of surveying the Aletsch Glacier and its surroundings for the publication of the map at the scale 1:10,000. For that purpose, several thousand bags filled with ashes and sawdust were dropped from an airplane to visibly mark the glacier's surface for easy recognition by the photogrammetrist.
In today's National Map series, the height of Mönch is 4107 m above sea level. Marking the 140th anniversary of Mönch's first ascent, this spot height was remeasured in 1997 using the most modern satellite-assisted surveying techniques called GPS (Global Positioning System). However, one must remember that already in 1840 geodesist Johannes Eschmann remarked that the top of a snow-covered mountain peak like Tödi, Mont-Blanc [and Mönch] can vary by seven meters due to evaporation or melting snow.