Count me as that glacier-guy with some insight on Dave's query and Deke's response on the role of glaciers in droughts. Glaciers can be viewed as water reservoirs that diminish drought severity. In drier or warmer than normal years, glaciers release some of their ice mass in addition to the seasonal snow accumulated that year. In colder or snowier years, not all the seasonal snow melts and the remaining seasonal snow adds to the glaciers' mass. Clearly this decade's drought has exceeded the ability of glaciers in the western US to avoid large areas of that region plunging into severe drought, but glaciers have helped the situation from being even worse. This winter's snowpack in the Pacific NW is well above normal, so I expect glaciers there will experience a year of net growth. I'm not aware if the same applies to the Rockies and southern Sierra Nevada ranges. Variations in glacier size (volume) are usually averaged over the period late fall to late fall, growing in winter and shrinking in summer. Interannual variations occur primarily driven by variations in winter snowfall and summer warmth. Nearly all glaciers, including those in the US, are receding and shrinking, losing more mass each year by melting than they gain in winter snowfall. Thus, their ability to diminish the severity of future droughts is declining.