Heavy rain can more than double glacier speeds in Alaska
Glaciers are often thought of as unyielding blocks of ice that slowly carve out the landscape as they move downhill by gravity. But sometimes their slow crawl becomes a surge that sees them move orders of magnitude faster than their usual speed.
Rain can significantly accelerate the movement of glaciers in Alaska, according to a study published in The Cryosphere. The research focused on the Sít Kusá Glacier, also known as Turner Glacier, which is known for its rapid surges. By analyzing GPS measurements taken every 15 seconds, the researchers found that rain events correlated with increases in the glacier's speed, sometimes by as much as 116%.
During slower periods, rain-induced surges were less common but still caused a 251% increase in speed, although at a slower overall rate. The study suggests that the efficiency of the glacier's drainage system plays a crucial role in these surges. When water cannot drain properly, it builds up pressure, reducing friction and allowing the glacier to slide more quickly over the underlying ground.
Understanding these mechanisms is essential for monitoring glacier instability and predicting future changes in sea levels due to climate change.
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