Modelling Subglacial Blisters and Transient Ice-Flow Anomalies Following Supraglacial Lake Drainage

On the Greenland Ice Sheet, drainage of supraglacial lakes via hydrofracture can transport substantial volumes of meltwater into the subglacial drainage system within hours, generating subglacial “blisters” that transiently accelerate adjacent ice flow. The blisters subsequently dissipate, with their thickness diminishing as water spreads laterally, propagates, and leaks into adjacent components of the subglacial drainage system. Although field observations reveal surface-elevation and velocity anomalies associated with blisters, existing subglacial hydrology models—typically comprised of linked cavities and channels—do not include the physics of elastic ice uplift, and therefore cannot reproduce the observed flood propagation or ice-flow anomalies.

We present a modelling framework that integrates elastic ice uplift with an established subglacial hydrology model of linked cavities and channels to model subglacial blisters and their interactions with the surrounding hydrological network. We further couple this framework to a depth-integrated ice-flow model, and simulate the resulting, transient surface-uplift and velocity anomalies following lake drainages. This unified model provides a new tool for interpreting remote-sensing and in situ observations of drainage events on short timescales, and for assessing how lake-drainage processes influence ice dynamics and the long-term mass balance of the Greenland Ice Sheet.