Working Group on Debris covered glaciers

(2018 – 2022, extended to 2023)

WG co-chairs

  • Lindsey Nicholson, University of Innsbruck, Austria
  • Francesca Pelliciotti, Swiss Federal Institute for Forest, Snow and Landscape Research , Switzerland
  • David Rounce, Carnegie Mellon University, USA


Many mountain ranges across the globe currently support abundant debris-covered glaciers, glaciers mantled for part of their tongues by a layer of rock debris. The proportion of the glacierized surface that is debris covered is expected to increase under continuing negative glacier mass balance due to ongoing climate change. Knowledge of how debris-covered glaciers will respond to climate will therefore have important implications for planning of hydrological resource, hazards associated with glacial lake outburst floods, and future global sea-level change.

Debris-covered glaciers are complex systems and their response to climate change is affected by multiple processes and factors including, but not limited to, the spatial extent of debris, debris thickness and other debris properties, rates of sub-debris melt, debris transport, the impact of ice cliffs, supraglacial ponds and subglacial processes, and changes in glacier dynamics. Some of these topics have been investigated for a while by now, and a number of alternative methods exist to assess e.g. melt under a uniform debris layer. Others are the subject of ongoing, very novel research efforts. This working group has chosen to focus on the more established areas of research, where it is possible and timely to conduct comparison of distinct approaches and a synthesis effort seems timely. Nevertheless, this working group is also determined to create a research platform for knowledge exchange and increased cooperation where all current research lines will find a place.

In the near future, the first regional maps of the areal extent of debris will become available. The logical next steps before debris can be included in regional and global models are to estimate the debris thickness and determine how sub-debris melt can be accurately quantified. While debris transport is important, its importance on regional runoff and sea-level projections over the next century still has to be established. Similarly, while the melt from ice cliffs, supraglacial ponds and subglacial processes is not insignificant, these are all relatively young areas of research that will need further progress before these processes can be quantified and their effect parameterised in large scale models. Therefore, the main objectives for the initial phase of this working group are to:

  • advance our ability to map debris thickness
  • identify the level of model complexity required to estimate sub-debris melt
  • coordinate knowledge exchange

These objectives will foster a step-change advance in our ability to incorporate debris thickness into regional and global models, while at the same time creating fertile ground for interaction and progress on the other important topics of current research outlined above.

Goals and Objectives

The overall goal is to provide – for the first time – a comparison of (1) debris thickness estimation methods and (2) sub-debris ablation models, in order to advance our understanding of how debris impacts glacier response and improve our ability to incorporate debris cover into larger-scale modeling efforts.

The specific objectives are to:

  • compare the available methods of mapping supra-glacial debris thickness, and assess their appropriateness for different applications
  • compare the performance of available sub-debris ablation models, and assess their appropriateness for different applications
  • work closely with the debris-covered glaciers research community to coordinate knowledge exchange

Open call for collaboration

We would like to engage as wide a group of scientists as possible in this working group, which will include young and senior scientists from a variety of geographic locations. In order to achieve this in a practical sense, we define two levels or participation: working group members and participants.

Members are expected to contribute to ALL of the following:

  • actively contribute to the development of at least one of the two comparison projects, which includes model design, forcing data, and output variables
  • produce model results for at least one of the comparison projects
  • participate in group workshops (as far as possible)

In addition to members, we also welcome working group participants from a wider sphere of related debris-covered glacier research topics.

Participants are expected to participate in discussions and meetings (if possible) AND contribute to AT LEAST ONE of the following:

  • contribute forcing data to one of the comparison projects
  • provide data or code to foster knowledge exchange
  • contribute services to journal special issues

Annual reports: 2020, 2021, 2022, 2023