Some days the grizzly bear watching in July and early August are quite warm so it is unlikely this was a “bath” rather think back on a hot day that you may have experienced and add a heavy fur coat. They are in the Glendale River estuary, which is a mixture of fresh and salt water so their coat will not contain much salt when dry. The sedge grass along the shore is the main reason for the grizzly bears to be in the area as the salmon to not appear until late August.