Alpine Archaeology: Some Effects of Climate and Altitude
Satellite Image over Alps, Spring
How do altitude and its attendant climatic results affect archaeology? Since 1994 we have an annual active learning experience about this relationship in the Stanford Alpine Archaeology Project.
Some general data about Alpine climate is apropos. Not only is the European Alpine high altitude above 2200 meters a cold biome but above the larch (Laryx sp. ) treeline generally between 1900-2100 meters in the Pennine Alps, summer temperatures range on average between -6 degrees Celsius to around 14 degrees Celsius. The average minimum precipitation in the Pennine Alps at 2200-2400 meters in the Grand-St-Bernard Pass is around 30 meters per year, at least 60% of which occurs as snow. Some years the precipitation exceeds 45 meters. The typical growing season above 2200 meters for shrubby plants (including mountain azalea and scrub juniper) is around 160 days. At night even summer temperatures often drop below freezing at elevations above 2200 meters. When warmer air masses from the Mediterranean in Italy meet the colder air masses of Northern Europe in Switzerland, a heavy fog often occurs around between 2200-2500 meters elevation with a thick cold air blanket in the passes between the continental divide where we work on the general border of the two countries. Within a few meters of each other in our site area, snow melt will flow either into the Mediterranean from the Po watershed or the Rhone watershed.
Temperature Map Year round (Swiss National Atlas)
The blue areas of Alpine Switzerland (including the Grand-St-Bernard pass region at near bottom left) have an annual median temperature not exceeding 5-7 degrees centigrade, essentially due to year round snowmass as a function of altitude, generally higher than 2000 meters.
Alpine region of Schreckhorn peak in late Winter/early Spring
The old adage that altitude mimics latitude is certainly true in the Alps, where it can snow any day of the year at 2472 meters (8200 ft elevation). We work in the Grand-St-Bernard Pass, at the montane junction of the Mont Blanc Massif and the Pennine Alps on an international border where Switzerland, Italy meet (we are also about 30 miles as the eagle flies from the French border). Last year's summer fieldwork was interrupted, as usual, by a mid-July snowfall that would in principle be lovely in December but is often frustrating when the fieldwork window is already narrow. Each year we usually have to wait until the winter snow melts to begin excavating, otherwise if we chop through snow and ice we have only muck underneath. If we wait too long, however, by mid-August the autumn begins early and we meet increasing snowfall again. This means that each year - depending on uncontrollable and rarely predictable variables - we have to be watching long-term European meteorology while still planning a fairly set time to do our annual fieldwork between July and August and hope for the best. Permanent active webcams set up across Switzerland assist us in accessing immediate snowfall melt data and inclement weather conditions while we are still stateside via the internet. Note the summer satellite image with storms building up from the west as the prevailing weather direction.
Satellite image over Alps, late fall / early winter, showing orographic storms approaching from west and building up over Jura Mtns in front of Bernese Oberland Alps.
We have often found that the shorter alpine spring and summer seasons of exposure to longer hours of sun (with photolysis) and rain (with hydrolysis) instead of snow, and the longer seasons of cold autumn and very cold winter during the year is actually a boon to archaeological preservation when materials and artifacts are in a frozen state at least six to eight months per year. Although many glaciers are apparently regressing at a faster rate and recent global warming trends are exposing such finds as the Neolithic Ice Man Otzi (5300 years BP), alpine archaeology can profit from much colder temperatures if the variable weather and field conditions can be optimized.
A full account of the most likely conditions and climatic effects (including organic preservation of artifacts by low diffusion in cold temperature) of alpine altitude on archaeological material is published in this author's book Alpine Archaeology (2007). Recent alpine finds such as the Neolithic-Copper Age threshold finds, including details of Otzi the Tyrolean Iceman (5300 BP) and other organic artifacts such as a Neolithic birchbark quiver found above Lenk, Switzerland, are discussed in this book.
TO READ MORE, SEE PATRICK HUNT'S ALPINE ARCHAEOLOGY BOOK (2007)
Dr. Patrick Hunt © 2005