Formation of a 1.5km Wide Ice Rubble Field from a 60cm Thick Flaw Lead in Eastern Canadian Beaufort Sea

During April 2008, ice property data were collected with helicopter-borne sensors along flight paths over the pack ice in the eastern Canadian Beaufort Sea using a Canadian Ice breaker, CCGS Amunsden, as a logistic base. Ice thickness, surface roughness data were collected with an Electromagnetic-Laser system and lead/floe distributions with a Video-Laser system. One strong wind event generated a large linear ice rubble field when the 60cm thick flaw lead, 18km wide, was crunched into land-fast by the 1.5m thick offshore pack ice. From imagery before and after the event and from data collected by the helicopter-borne sensors it was found that the original 18km wide flaw lead became a 1.3-1.4km wide rubble field with an average thickness of 8m. The change does account for the ice volume of the original flaw lead. When the wind reversed a new flaw lead opened up leaving the newly formed rubble field attached to and become part of the original land-fast ice. The observations are an excellent validation data set for ice-ocean forecast models trying to forecast ice features such as rubble field formation that during the pack ice evolution would represent an ice hazards to navigation.