Snow cover and duration are very variable components of the alpine
environment and are often poorly reproduced in climate models. Using
joint probability temperature/precipitation distributions to categorize
cold/dry, cold/moist, warm/dry (WD) and warm/moist situations in winter,
this study demonstrates that one particular mode (WD) exerts the
strongest influence on snow. When the number of WD days is low, snow in
the Swiss Alps is abundant, and vice versa. Since the 1950s, there has
been an increase in the WD events and a subsequent reduction in snow
cover. Snow-abundant winters have nevertheless occurred in recent years,
when WD days are low, despite winter temperatures that are more than 1
degrees C higher than those in the mid-1900s. The WD mode thus
represents a form of proxy to snow amount and duration; its evolution in
an enhanced greenhouse climate can help identify whether snow-abundant
winters may still occur in a much warmer world. Copyright. (C) 2010
Royal Meteorological Society