Plain Language Summary
Retrogressive thaw slumps (thaw slumps) are a form of landslide that
occurs when thick layers of ice under the ground are exposed and thaw,
creating muddy flows that can grow to cover thousands of
m2 in just a few years. These processes are occurring
more frequently in the western Canadian Arctic during the last two
decades, becoming one of the primary causes of landscape change. This
research examines how variation in the ice and overlying soil thickness
of the thaw slump headwalls (a prominent, near vertical cliff at the
back of a thaw slump), affects their rate of growth. We find that a
persistent layer of ice, and a thin soil overburden, tends to promote
headwall retreat rates much faster than otherwise. We also show how
simple, cost-effective and quick measurements can be used to map the
buried ice and show how it varies inland, and then use this information
to improve predictions of how fast the headwall will retreat. This
research suggests that detailed knowledge of how the internal ice and
overburden layering varies is critical to understanding how thaw slumps
evolve and to predict their development.