The Bering Glacier is the largest glacier in North America, covering an area of about 1,900 square miles in Alaska and Canada. It is part of the Bagley Icefield, the largest icefield outside of the polar regions. The glacier flows from the icefield to the Gulf of Alaska, where it ends at the edge of Vitus Lake. The lake empties into the gulf by way of the Seal River, carrying 6.5 trillion tons of water from the glacier every year1
But the Bering Glacier is not just a massive block of ice. It is also a dynamic and complex system that changes over time, revealing hidden features and secrets. A trippy satellite map of the glacier, created by NASA’s Earth Observatory, shows some of these fascinating details2
One of the most striking features on the map is the hidden lagoon that appears near the terminus of the glacier. This lagoon is actually a subglacial lake, meaning that it is trapped under the ice. The lake formed as a result of the glacier’s surge, a periodic event that occurs when the glacier moves faster than usual due to increased pressure from the icefield. The surge causes the glacier to advance and push against the land, creating a dam that blocks the flow of water from Vitus Lake. The water then accumulates under the glacier, forming a subglacial lake2
The subglacial lake is not visible from the surface, but it can be detected by satellite radar. The radar waves can penetrate the ice and reflect off the water, creating a bright spot on the map. The lake is estimated to be about 6 miles long and 2.5 miles wide, and it contains about 4 cubic miles of water. The lake is also very deep, reaching a maximum depth of about 1,640 feet2
The subglacial lake is not stable, however. It can drain suddenly when the glacier retreats or when the ice dam breaks. This can cause a massive flood that can affect the downstream environment and communities. The last major drainage event occurred in 1994, when the lake released about 3.7 cubic miles of water in less than a week. The flood increased the discharge of the Seal River by 25 times, and raised the water level of Vitus Lake by 15 feet. The flood also carried large amounts of sediment and debris, creating a muddy plume that extended into the Gulf of Alaska2
Another interesting feature on the map is the medial moraine that runs along the center of the glacier. A moraine is a ridge of rock and soil that is deposited by a glacier as it moves. A medial moraine forms when two glaciers merge and carry their lateral moraines (the ones on the sides) to the middle. The medial moraine on the Bering Glacier is composed of material from the Steller and Quintino Sella Glaciers, which are two of the main tributaries of the Bering Glacier. The moraine acts as a marker of the glacier’s flow and history, and it also influences the glacier’s dynamics and stability2
The map also shows the crevasses that crisscross the surface of the glacier. Crevasses are cracks or fissures that form when the glacier bends or breaks due to stress or strain. Crevasses can vary in size and shape, depending on the glacier’s speed, thickness, slope, and temperature. Crevasses can be dangerous for people and animals that traverse the glacier, but they can also be useful for studying the glacier’s structure and movement. Crevasses can also affect the glacier’s melting and calving, as they expose more surface area to the air and water2
The Bering Glacier is a remarkable natural wonder that deserves our attention and appreciation. It is not only the largest glacier in North America, but also a living and changing entity that reveals hidden lagoon and other secrets. The trippy satellite map of the glacier, created by NASA’s Earth Observatory, helps us to see and understand the glacier’s beauty and complexity2
إرسال تعليق