Today, we awoke aboard the National Geographic Sea Bird to find the ship winding its way through Tracy Arm, a long narrow fjord that terminates at the magnificent Sawyer and South Sawyer Glaciers. The steep walls of the fjord, shaped by flowing Pleistocene ice, rose vertically from the silty-green water. Behind them, pointed peaks could be seen that were spared from the glacier’s erosive powers by their commanding heights. We continued cruising until we could see the South Sawyer Glacier, then dropped anchor and set off to explore the fjord in the expedition landing crafts.

From the small crafts, we observed pairs of Arctic terns dancing over the water in ritualized breeding displays. Iceberg sculptures, some brilliant blue and others crystal clear, drifted by with the incoming tide, while harbor seals bobbed and weaved among them. Throughout, the glacier remained quiet until a small piece of ice broke free and splashed into the water below. And then, as if it had been waiting its turn, a second block of ice took the plunge, this time with a louder splash than before. A flock of terns that had been circling nearby began to dive for small fish that were stunned by the concussive force of the falling ice. Next was a thunderous avalanche of ice that drove waves up onto the rock wall at the glacier’s edge.

This continued, with each event seemingly triggering the next and drawing cheers from the onlookers, until suddenly a giant wall of ice began to emerge from the water. At first it seemed to be an illusion, as though our eyes had been fooled from staring too intently at the cascading ice. But the upheaval continued and the giant block of ice rose nearly to the height of the glacier itself before plunging back down into the churning water. We all watched with disbelief and excitement as the huge iceberg floated away from the glacier.  Eventually, it came to rest and some of us were able to approach it for a closer look. Part cobalt blue, part frosted blue, and as large as our ship, the massive block of ice lay dormant on its side. We had just witnessed an incredible display that inspired a sense of awe and wonderment.