Leads and Associated Sea Ice Drift in the Beaufort Sea in Winter

Beaufort Sea ice motion is episodic in winter, on average following the anticyclonic motion of the Beaufort Gyre. Weather systems cause the ice pack to fracture in characteristic patterns that depend on the location and trajectory of the weather system in relation to the coast. The majority of leads associated with anticyclonic motion in the Beaufort Sea are coastal leads that form perpendicular from promontories along the coast and landfast ice edge. Between 40% and 90% (depending on location along the Beaufort coast) winter sea ice motion is associated with leads, including coastal leads, coastal flaw leads, and interior lead patterns. In winter much of the Beaufort Gyre ice drift results from ice‐coast interaction, with high ice drift localized on the leeward side of fractures that propagate from the coast. In the vicinity of Point Barrow, which has the largest occurrence of coastal leads, ice drift rates are enhanced due to this ice‐coast interaction. No trends in occurrence of these leads are found over the 20 winters from December 1993 to May 2013. Seasonality in the occurrence of the leads follows seasonality in the location of the Beaufort High. In order for ice to be transported from the northeast part of the Beaufort Gyre to the southwest in a single winter, anticyclones would need to break their geospatial climatic norm, needing a higher prevalence of anticyclones in the eastern Beaufort early in the season and higher prevalence in the west Canada Basin later in the season.