Alaskan Glacial Lakes Expanding at Unprecedented Rates as Melting Accelerates According to New Colorado State University Study

New research from CSU shows Alaskan glacial lakes are expanding at record speeds, identifying basins where water will pool as glaciers continue to melt.

By: AXL Media

Published: Mar 12, 2026, 11:23 AM EDT

Source: Information for this report was sourced from Colorado State University

Staggering Acceleration of Glacial Lake Expansion

New research from Colorado State University indicates that the landscape of Alaska is shifting at a pace that has shocked even seasoned glaciologists. Between 2018 and 2024, glacial lakes in the region expanded by approximately 60 square miles, a growth rate 50% higher than that recorded between 2009 and 2018. Lead author Dan McGrath, an associate professor of geosciences, noted that while dramatic glacier retreat is now common, the scale of change over the last six years is staggering. This rapid expansion is a direct result of melting ice filling the voids left behind as glaciers withdraw further into the mountain ranges.

The Destructive Potential of Outburst Flooding

The primary concern regarding these growing bodies of water is the threat of glacial lake outburst floods (GLOFs). These events occur when a lake suddenly and destructively drains, sending massive volumes of water downstream toward human infrastructure and ecosystems. While much of Alaska remains sparsely populated, the impacts are already being felt in urban centers. For instance, neighborhoods along the Mendenhall River in Juneau have faced repeated inundation from Suicide Basin. As these lakes store more water, the potential magnitude and frequency of these catastrophic floods increase, placing bridges, roads, and railroads at higher risk.

Mapping the Hidden Terrain Beneath the Ice

To predict where future lakes will form, researchers utilized advanced elevation and ice-thickness data to map the land surface currently hidden beneath glaciers. The study demonstrated that 80% of recent lake growth occurred within "overdeepenings," which are deep basins carved into the bedrock by the weight and movement of the ice. For the first time, scientists have been able to show a direct correspondence between these landscape features and the formation of new lakes. This subsurface mapping allows land managers to see where water will naturally pool as glaciers continue their inevitable retreat in the coming decades.