This paper reveals a new mode of winter (October--March) monthly mean atmospheric intraseasonal variability characterized by a seesaw structure in sea level pressure (SLP) anomalies between the Barents Sea and the Beaufort Sea with an equivalent barotropic structure. The Beaufort High varies out of phase with the Siberian High. Compared to the Arctic Oscillation (AO) and the dipole anomaly, the effect of this mode on Fram Strait sea ice flux is the most important so far, although it accounts for only 9.1% of the variance. The Beaufort High itself is not crucial for sea ice flux through Fram Strait.