The North Atlantic Oscillation and snow avalanching in Iceland

The number of snow avalanche cycles occurring in Iceland is correlated to a major source of variability in climate, the North Atlantic Oscillation. A new index for this oscillation is produced that reflects the cumulative effect of snow build‐up in a starting zone. An analysis of the time‐series for this index shows that recent avalanche tragedies in Iceland are linked to a rise in this index. Consequently, estimations of avalanche return periods and thus, avalanche hazard zones, may need re‐evaluation. Because the oscillation has an impact upon climate throughout the Northern Hemisphere, this may be necessary in a number of other countries.