Since 1977 ablation-season temperature has been 1.1°C above the 1930–80 mean and winter precipitation has been 14% below the 1930–80 mean. In order to identify the effect of this climatic fluctuation on North Cascade glaciers, the North Cascade Glacier-Climate Project has monitored the terminus behavior of 107 glaciers between 1983 and 1988.

The 107 glaciers examined represent six climate sensitivity groups. Each group has a different sensitivity to the four primary climatic parameters: (1) ablation-season temperature, (2) accumulation-season precipitation, (3) summer cloud cover and (4) freezing levels during May and October precipitation events. A glacier’s sensitivity to each climatic parameter is determined by its geographic location and topographic position. Each sensitivity type has specific geographic and topographic characteristics, such as degree of radiational shading, orientation, altitude with respect to the local glaciation threshold, accumulation sources, and distance from the Cascade Crest. Accumulation sources are direct snowfall, wind drifting and avalanching.

Of the 107 glaciers examined, 91 had retreated significantly between 1983 and 1988 and three had advanced. Correlation of retreat rate and climatic sensitivity type indicates that the higher a glacier’s winter balance, the smaller the retreat rate. High-altitude accumulation zones, multiple accumulation sources and a northward orientation are all associated with higher winter balances. Retreat was greatest for glaciers with poor radiational shading, and only direct snowfall accumulation. Retreat rate was slowest for glaciers with multiple accumulation sources and a northward orientation, though not necessarily good radiational shading. Retreat rate increased with distance east of the Cascade Crest and retreat rate was high for low-altitude glaciers.