The alpine late-glacial period ended approximately 11,600 years ago with the recession of Ice Age glaciers to the Holocene or recent size (e.g. as around 1850). Since then, alpine glaciers have been fluctuating within a narrowly limited range only at a high temperature level and an astonishingly low amplitude (± 1 °C). There is conclusive evidence, based on historical glaciology studies, of eight major advance cycles and as many retreat phases covering the last 11,600 years (Holocene, postglacial). During these Holocene cold phases, the glacier delineation and tongue positions always attained comparable extents and ranges.

The advance phase around 1850, with its striking moraine zones (terminal and embankment moraines) constitutes the culmination and conclusion of this period of generally major glacier extents lasting over several centuries. This phase is commonly referred to as the «Little Ice Age» (period of 1250 to 1850, approx.). The glacier forefields, subsequently freed from ice, can be recognized by the areas of fresh morainic debris and the as-yet sparse vegetation. In the cool phases of the Holocene, these pro-glacial areas were repeatedly covered with ice, and then became ice-free in the retreat phases. For this reason, the maximum extent of 1850 serves as a key variable for determining and calibrating the climatic fluctuations of the Holocene.

This phase is well documented (e.g., with maps and pictures) based on historical records from the period around the middle of the 19th century. The glaciers of the Alps were depicted at the point of their last maximum extent in the first overall topographic record of Switzerland (for the making of the Dufour map, at a scale of 1:100,000). Glaciomorphological findings enable a detailed reconstruction of the glacier extent around 1850. In such manner, extensive data were collected, and in comparison with the current situation (Swiss Glacier Inventories of 1973 and 1998) it was possible to illustrate and analyze the «retreat of the century».

The glaciated surface of the Swiss Alps diminished from 1800 km² in 1850 to 1300 km² in 1973 and to 860 km² in 2023. With reference to the surface area of Switzerland, the glaciated portion was reduced from 4.4% to around 2%. Large glaciers, such as the Grosser Aletsch, Gorner, and Morteratsch had the greatest amount of recession, with respect to surface area, volume and length values, seen in absolute terms. However, their losses were less, at 10 to 25 %, than the medium-sized glaciers, at 30–50%, or the small glaciers, at 50 to 80%. Several hundred small firn patches melted away completely during the last 150 years. The retreat tendency is continuing at present and seems even to be accelerating, in line with climatic developments (glacier retreat scenario for 2050).