Alaska's Glaciers: How do they happen? And do they really move?

Published: Jan 01, 2021
Last Updated: Nov 30, 2023

Alaska boasts many treasures, but one of the most beloved are our breathtaking glaciers. These massive sheets of ice are large enough that their pasts are carved into the towering mountains that often surround them; these glacier-made features are called cirques.


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Glacier Bay, AK (Photo / CC BY)


These kind of glaciers are alpine glaciers, which form on the slopes and crests of mountains, Alaska has many of these. We also have many tidewater glaciers, which terminate directly into the ocean. Glaciers larger than 50,000 kilometers are called continental glaciers, like those in Antarctica.

Glaciers form when snow and ice build up faster than it can melt, over very long periods of time. As they build up, or grow, they become extremely heavy, creating glacial ice. This ice looks white from the top, where tiny air bubbles accumulate, but in the middle they are bright blue! (This happens because of infrared light.) If you’re lucky, a piece of the glacier will calve, or fall off, when you’re there––it’s an dramatic and exciting thing to see, and it exposes that gorgeous color.


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Calving at Holgate Glacier, AK (Photo by ecastro / CC BY)


In addition to growing and shrinking, glaciers also move! Due to gravity and that immense weight glaciers move slowly downhill, sort of like a very slow river. Glaciers leave land features called moraines in their wake, these are composed of glacial flour and silt––extremely fine sand-like substances, be sure to touch some on your trip!

Developing moraine in, AK (Photo by ecastro / CC BY)


Now comes the tricky part: Choosing which tour! The Juneau Mendenhall Glacier Ice Adventure Tour takes you away from the crowds via native-style canoe paddle across Mendenhall Lake, where you’ll also learn all about the famous Mendenhall Glacier and other entertaining information from your friendly guide. Once there it’s time for a glacier-top hike––and even into an ice cave to see that bright blue close up! (Conditions permitting.)

Mendenhall Glacier Ice Cave near Juneau, AK (Photo by ecastro / CC BY)


The Juneau Mendenhall Glacier Guided Walk via Helicopter takes you soaring through the air over rainforest, lakes, and stunning glacial ice features, while you learn all about them. Then it’s time to land––directly onto the Mendenhall Glacier! Once landed, you’ll enjoy a short guided walk on top of the glacier.

Juneau Mendenhall Glacier Guided Walk via Helicopter (Photo by ecastro / CC BY)


Finally we have our Juneau Taku Glacier Lodge Flight and Feast, which takes you completely off the beaten path to remote wilderness. You’ll get there via seaplane, passing FIVE glaciers on the way! The Taku River will act as your landing strip when you arrive at Taku Lodge, directly across the river from Hole in the Wall Glacier. You’ll have time to wander the short walking paths, grab a drink of choice, or explore the lodge before the all-you-can-eat feast!

Juneau Taku Glacier Lodge Flight & Feast (Photo by ecastro / CC BY)


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