Fast variability of the outflow in the Z CMa system

High-resolution, time-resolved spectroscopic observations of Z CMa carried out on 1997 January 14–17 are presented. Large night-to-night and hour-to-hour variations in Hα, Hβ and Na i D P Cygni absorptions, as well as an Hβ emission peak, were observed. Variations in the red wings of the hydrogen emission lines were also detected. The high-velocity wide-emission component on the blue side of Hα appeared on January 17. The observations are discussed in the framework of current wind models.