After days of unusually warm weather, the brisk chill in the air this morning was a welcome change. The dropping temperature was a sign that we were nearing our destination: South Sawyer Glacier at the terminus of Tracy Arm Fjord. Cold air pools over icefields high in the mountains and then rushes down the fjord in a form of convection known as a katabatic wind.

Undeterred, guests and staff bundled up in warm layers to enjoy the stunning scenery as National Geographic Sea Bird cruised through the fjord before breakfast.

Our morning of glacier watching rewarded us with two large calving events and excellent views of harbor seals hauled out on ice. These animals seek refuge from predators on the ice floes at the base of tidewater glaciers and bear their pups in the relative safety of the ice. But tidewater glaciers are receding rapidly, and we must wonder what will happen to these creatures when, at last, the glaciers cease to deposit ice into the fjord.