December 08, 2006
The photo above showing strips of sea ice in the Arctic Ocean was taken on September 5, 2005. If the air is cold but the sea calm, nilas ice can form. Nilas is composed of both frazil and congelation ice crystals -- the frazil ice crystals lying above the congelation ice in vertical cross section. Nilas ice is thin (<10 cm or 4 in), nearly transparent and elastic, which allows it to easily bend and flex in a wave field. Note that September is typically the month of minimum sea ice extent in the Arctic Ocean. In September 2005, the ice extent was less than that observed in any year during the satellite era (since the late 1960s).