Photogrammetry as a Tool for Glacier Monitoring in the USA Robert Krimmel rkrimmel@usgs.gov Edward Josberger ejosberg@usgs.gov Ice and Climate Project U.S. Geological Survey Tacoma, WA 98402 Abstract Several glaciers in the Washington State and Alaska have been monitored for up to 4 decades for changes in surface altitude, terminus position, velocity, and mass balance. The mass balance at Wolverine Glacier, Gulkana Glacier, South Cascade Glacier, and Blue Glacier has been measured annually by surface or inferred methods since as early as 1953. An important check on these surface methods is the absolute change in volume as determined by photogrammetry. At South Cascade Glacier DEMs have been formed photogrammetrically 25 times since 1958. At other glaciers, DEMs at several year intervals improve the confidence level of the annual mass balance measurements. Columbia Glacier is a major tidewater glacier in Alaska and has been rapidly retreating since 1982. Surface lowering, terminus position, calving rate, and ice velocity have been measured using date to date comparison forming a unique 26 year time series of these changes. Other glaciers, notably Bering and Hubbard, two of North America's largest, have been monitored through surge cycles and a fjord closure using aerial photography.