Satellite Map Uncovers ‘Hidden Lagoon’ and Other Mysteries of North America’s Largest Glacier

By: Georgia | Published: Dec 11, 2023

NASA has released a striking false-color image of Alaska’s Malaspina Glacier, revealing previously hidden aspects of this massive ice formation. Thanks to this image, several discoveries have been made, including the revelation of a previously unseen lagoon.

Captured by NASA’s Landsat 9 satellite, this image provides a unique perspective on one of North America’s largest glaciers.

Malaspina Glacier: A Geographic Titan

Covering approximately 1,680 square miles and located in Wrangell-St. Elias National Park in Southeastern Alaska, the Malaspina Glacier is North America’s largest glacier and the world’s largest piedmont glacier. 

The photograph captures a sweeping aerial view of a vast snow-covered mountain range under a clear sky

Source: Wikimedia Commons

Distinguished by its lobed form, this type of glacier spreads out from mountainous regions onto flatter land. It is a significant geographical feature in the region thanks to its enormous size and unique shape.


Interpreting NASA's Colorful Image

NASA’s image of Malaspina Glacier uses false-color imaging to differentiate between various elements of the glacier. In this technique, infrared radiation helps distinguish between ice, water, land, and vegetation. 

A false-color satellite image showcasing the Malaspina Glacier in the center with vivid yellow and gold tones swirling like eddies, labeled clearly on the image. To the north, the Seward Glacier and Agassiz Glacier are labeled, depicted in bright turquoise and orange hues, indicating ice and vegetation

Source: Wanmei Liang/Landsat/NASA Earth Observatory

The yellow and orange hues represent ice, red indicates water, and blue and green colors mark land and vegetation, respectively. This method provides valuable insight into the glacier’s composition.

The Discovery of a Hidden Lagoon

The recent image has revealed a ‘hidden lagoon’ located between the ice and land at the glacier’s edge. This body of water is unique due to its saltwater composition, which is warmer than previously thought.

An overhead satellite image displaying the vast Malaspina Glacier with layered streaks of ice and sediment flowing outward. Surrounding glaciers, including the Libby, Agassiz, Marvine, and Hayden Glaciers, are labeled, showing their proximity to Malaspina

Source: Jesse Allen/Landsat/NASA Earth Observatory

The discovery of this lagoon is important, as it could have consequences for the current understanding of glacial melting processes.

Malaspina's Moraines: A Geological Record

The ripples and folds visible on the surface of Malaspina Glacier are moraines, which are bands of soil, rock, and debris. These features are formed as the glacier moves and collects material along its path.

The image offers an aerial view of a glacier's surface taken from a small aircraft, as evidenced by the wing's strut in the upper left corner. The glacier is marked by dark and light striations, showing the patterns of accumulated ice and moraines

Source: Wikimedia Commons

Moraines serve as a geological record, providing evidence of the glacier’s historical movements and the natural processes that are involved in shaping it.

Adjacent Glaciers: Seward and Agassiz

In addition to Malaspina, the satellite image also shows nearby glaciers, namely the Seward and Agassiz Glaciers.

A striking landscape featuring a wide glacier flowing through a mountainous valley. In the foreground, rugged terrain with green vegetation is visible, leading towards the expansive, icy surface of the glacier

Source: Wikimedia Commons

These glaciers, fed by the Saint Elias Mountains, are part of the same glacial system and contribute to the overall understanding of glacial behavior in the region. 


Reassessing Malaspina's Ice Volume

A study published in the Journal of Geophysical Research: Earth Surface has shown that the volume of Malaspina Glacier’s ice had previously been overestimated by about 30%. 

A digital 3D topographic representation of a glacial valley with distinct blue and white bands depicting the glacier's flow

Source: Wikimedia Commons

Despite this, the study suggests that a complete melt of the glacier could raise global sea levels by 0.06 inches, highlighting the potential impact of glacial melting on global sea levels.


Saltwater Lagoon's Impact on Ice Melt

The saltwater lagoon discovered within the glacier is warmer due to its high salt content. This characteristic of the lagoon is crucial as it could influence the rate at which the surrounding ice melts. 

The image captures a bird's-eye view of a broad glacier nestled between mountain ranges. The glacier's surface is characterized by concentric lines and patterns indicative of its flow and the accumulation of sediments

Source: Wikimedia Commons

The presence of such warm water bodies within glaciers is an important factor in studying glacial dynamics.


Subglacial Water Channels: An Underlying Network

Researchers have also identified extensive subglacial channels running through the bedrock beneath Malaspina Glacier.

Glacial landscape viewed from above, showing a vast, pale glacier surrounded by rugged terrain. The glacier spills into a central basin, with striations indicating ice flow. Surrounding the ice are green areas representing vegetation, and blue tones for water bodies, including rivers feeding into the glacier's basin

Source: Wikimedia Commons

These channels, extending up to 22 miles under the ice, play a notable role in the glacier’s movement and melting patterns.


A Window into Earth's Glaciers

The Landsat 9 satellite, a joint project between NASA and the U.S. Geological Survey was instrumental in capturing this detailed image of Malaspina Glacier.

Landsat 9 satellite orbiting Earth, with its large solar panel arrays fully extended

Source: Wikimedia Commons

The satellite’s ability to provide such high-resolution, false-color images is invaluable in studying Earth’s natural features and keeping an eye on environmental changes.


The Glacier's Indigenous Name

The Malaspina Glacier is also known by its indigenous name, Sít’ Tlein, which means ‘big glacier’ in the Tlingit language. 

An aerial photograph captures the expansive Malaspina Glacier in Alaska, with its intricate patterns of ice and sediment forming natural, wave-like striations. The glacier is nestled among mountain ranges, with the peaks rising ruggedly in the background, partially covered in snow

Source: Wikimedia Commons

This name, given by the Indigenous people of the area, reflects the cultural significance of the glacier and the deep connection between the natural world and local communities.


Global Implications of Malaspina Glacier's Study

The study of Malaspina Glacier extends beyond its geographical and environmental aspects. Understanding this glacier, its behavior, and its changes is crucial in the broader context of climate research and sea-level studies.

A satellite image in false-color depicts Malaspina Glacier, with the ice shown in shades of gray and white, flowing into a dark blue sea. Surrounding the glacier, the land and vegetation are represented in vivid red, contrasting starkly with the ice

Source: Wikimedia Commons

The insights gained from Malaspina Glacier contribute to the global understanding of glacial dynamics and their implications for Earth’s climate system.