On the basis of an analysis of data from four sample plots at Ust'‐Yeniseysk, the author presents a detailed study of the sequence of events associated with the freezing and thawing of the active layer. By the time freezing was complete the active layer had assumed a binary structure with an upper streaky horizon with streaks of segregated ice, overlying a horizon with a massive cryogenic texture. This arrangement persisted for much of the winter but significant changes occurred once thawing had begun; specifically in much of the lower zone the massive cryogenic texture was replaced by a streaky texture, i.e., formation of streaks of segregated ice was occurring in the still frozen part of the active layer while thawing was proceeding from the surface. The author has correlated variations in this and other phenomena with differences in moisture content, temperature gradients and rates of thawing. (The translation is by William Barr, University of Saskatchewan.)