During the time that ice is present in the Bering Strait, it is constantly moving, both northward and southward, subject to wind and current stresses. There were, however, several times in the last decade when the ice was prevented from travelling through the Strait. The blockage of ice was due to the formation of fairly stable double arches that extended across the Strait.

Six episodes of double arch formation, resulting in ice blockage in the Bering Strait, were recorded on NOAA satellite imagery spanning the last eleven years; one additional episode was seen on Landsat imagery. All of the incidences of double arching occurred between February and May. In the most extreme case the arches prevented the southward flow of ice through the Strait for at least 27 days during April and May 1980.