The climatic state in the Beaufort Sea in 1997 was characterized by warmer atmosphere, smaller areal coverage of sea ice in summer than average, and an oceanic mixed layer with a relatively low salinity that persisted into fall and early winter. The most remarkable change occurred near the end of 1997 when both salinity and temperature in the upper layer varied dramatically in a short-time period. The evolution of the air-sea-ice condition was observed by an autonomous buoy. The buoy observation revealed that deep mixing that penetrated through the Arctic halocline occurred in response to enhanced wind-stress forcing associated with an intense storm and was mainly responsible for the abrupt change of temperature and salinity in the mixed layer near the end of 1997. Similar events were inferred from storms in the Eurasian basin in 1994. We postulate that synoptic storms plays a very important role in the variations of the heat and salt budgets in the upper Arctic Ocean. ¿ 2001 American Geophysical Union