The research team has tracked this glacier's movement for eleven consecutive seasons, expecting the slow, well-documented acceleration typical of glaciers in the region. This year's measurements came in at roughly double the historical rate.
Their first instinct was to suspect an instrument error. A second, independent measurement using a different method confirmed the number: the glacier really had moved that much faster, in a single season, than any prior year on record.
A number nobody expected yet
The team is cautious about attributing a single season's anomaly to any one cause. Glacial movement depends on a tangle of factors — meltwater lubrication at the base, ice thickness, underlying bedrock — that don't always move in the same direction.
What they can say with more confidence is that the models used to project this glacier's future may need revisiting sooner than planned. A rate this far outside historical variance is exactly the kind of data point that forces a model back to the drawing board.