This study presents physical and stable isotopic properties of sea ice in the southernmost section of the Sea of Okhotsk on the basis of observations and measurements made in 1995 and 1996 midwinter cruises. Structural analysis revealed that ice was predominantly of the granular type. Saucer-shaped cores and wedges were seen in the cross sections of the pancakes, which indicate a rafting event in the early stage of the pancake formation. The fraction of snow with respect to the total ice mass was estimated at ~8% from independent Δ18O and density measurements. From these findings we conclude that the initial growth mechanisms of the sea ice over this region are by the frazil pancake cycle with rafting and by the snow ice formation. Analysis also shows that the formation of the snow ice induces ~10% more salt flux through the additional freezing of the seawater. In a short (synoptic) timescale this implies that snow becomes a negative (salting) rather than a positive (freshening) source for the buoyancy flux. These results suggest critical influence of the rapid formation of the frazil pancakes and snow ice under stormy conditions on the salt and buoyancy fluxes over the region. ¿ 2000 American Geophysical Union