watervulnerability

Shasta Trinity National Forest Watershed Vulnerability Assessment, Pacific Southwest Region (R5)
Figure 6. Shasta Trinity National Forest Trends in Precipitation Variability
Forest Snow Depth and Mount Shasta Glacier Trends
Minimum and mean snow depths at all snow stations on the Forest have decreased (Figure 7). Maximum
snow depth at all stations in the Trinity River basin has decreased over the period of record. This trend is
not consistent across the Forest, as maximum snow depths in the Central Valley Region (the Southern
Cascade Province, Figure 7) are increasing. Growth of glaciers on Mount Shasta is consistent with
increase in maximum depths in the Southern Cascades (Figure 7). Shasta’s glaciers are among the few in
the world that are still growing. Glacier changes are dictated by air temperature and precipitation.
Warming can lead to increases in precipitation (and thus glacier ice accumulation) (Nesje et al. 2008).
191 Assessing the Vulnerability of Watersheds to Climate Change