Columbia Glacier, in Prince William Sound, Alaska, continued its rapid retreat in 1986, with a retreat of 800 m. Average velocity of the lower portion of the glacier, 10 September 1986 to 26 January 1987, was three km/yr, or about one-half of the velocity during similar periods for the previous three years. This reduced velocity is a new development in the progression of the retreat, and if the calving rate follows the pattern of previous years, will result in continued retreat. (Author 's abstract)