A Unified Blister and Subglacial Hydrology Framework for Supraglacial Lake Drainage Events

TL;DR

This paper introduces a comprehensive model that couples blister formation with subglacial hydrology, capturing transient responses to lake drainage events and explaining seasonal differences in blister behavior and water pathways.

Contribution

It presents a novel unified framework that extends existing models to simulate blister evolution and their impact on subglacial water flow during rapid lake drainage.

Findings

Summer drainage causes short-lived blisters that leak into existing channels.

Winter drainage results in persistent blisters that dominate water pathways.

Model simulations align with field observations of surface uplift and ice velocity changes.

Abstract

Subglacial blisters form due to the rapid drainage of supraglacial lakes into grounded ice sheets, and are characterised by elastic ice uplift and transient ice-velocity anomalies. Although blister occurrence is confirmed by observations, the dynamics of blisters and their impacts on ice flow remain poorly represented in current subglacial hydrology models, as typical cavity-channel system models cannot capture short-timescale blister formation, propagation, and relaxation. Here we present a unified, self-consistent modelling framework that directly couples blister evolution with the subglacial drainage system, extending existing subglacial hydrology models to account for transient responses to rapid lake drainage events. Numerical simulations, validated by field observations, reveal distinct seasonal behavior: during summer, lake drainage generates short-lived blisters that rapidly leak water into a pre-existing drainage system of efficient, channelised water pathways, whereas winter drainage results in persistent blisters that propagate and serve as the primary meltwater pathway at the ice-bed interface. The dynamics of blister propagation and leakage in our model are governed by effective viscosity and a characteristic leakage length scale, which reflects the connection between the blister and the surrounding hydrological network. This unified model offers a valuable tool for investigating blister dynamics and their interplay with subglacial hydrology, facilitating the interpretation of observed surface uplift and ice-velocity variations following supraglacial lake drainage events.