How would you briefly describe your project (WP6) – what is the core question you are trying to answer?

– We are trying to understand how and where meltwater is stored within Antarctic ice, and what that means for future stability. The core question is: how do hidden water reservoirs affect the ice’s resilience, motion and the risk of collapse?

You study both firn aquifers and supraglacial lakes – what are they, and are they connected?

– Firn aquifers are water reservoirs within the snow, while supraglacial lakes are bodies of water that collect on top of the ice surface. They are connected in the sense that both show Antarctica is beginning to store more meltwater than before—but they function in different ways. A lake is visible on the surface and can drain rapidly through cracks, whereas an aquifer is more like a sponge that slowly fills from within.

Why is it important that a firn aquifer is multi-year?

– If an aquifer persists from year to year, it means the system does not have time to refreeze—an indication of a warmer climate. It also means large amounts of water can be stored, which could affect the ice’s mechanical properties in the future, says Katrin Lindbäck.

How can water stored in snow and ice contribute to cracks and, ultimately, the collapse of an ice shelf?

– Water is heavy. When it accumulates in lakes or is forced down into crevasses, it acts like a hydraulic jack, prying the cracks open and driving them deeper. This is called hydrofracturing. If many lakes drain at the same time, an entire ice shelf can weaken and, in the worst case, collapse.

How do you actually go about looking for invisible water inside snow and ice?

– We use ground-penetrating radar and sensors to “scan” the ice. Radar signals are sent down into the snow and reflected back when they hit something different from the surrounding material—for example, water. This allows us to map layers, boundaries and potential aquifers without digging.

What do you think could surprise you the most: that there is more water stored in the ice than expected, or that it behaves differently? And what would that imply?

– The biggest surprise would be if the water moves horizontally over longer distances than we think—or if the aquifers turn out to be larger and more complex. That would mean Antarctica’s hydrology is far more dynamic than the models assume, which affects how we assess the risk of instability.

How do you use ground-penetrating radar (GPR) in the field – what can it reveal that neither the eye nor satellites can see?

– The eye only sees the surface. Satellites see the surface and sometimes large lakes. But radar can detect structures and water 20–100 metres down in the snow. It reveals layer boundaries, ice blocks, melt layers and where the water is—even small amounts that no other method can detect.

You also measure with sensors (snow depth, temperature/moisture, pressure). What signals are you looking for that link weather and incoming radiation to how much water can form and be stored?

– We track:

• temperature profiles in the firn – how deeply heat penetrates
• snow depth – whether snow insulates or melts
• moisture and pressure – signs that water is flowing or accumulating
• solar radiation and wind – how the surface warms or cools

– Together, these show when and where conditions are warm enough to produce meltwater that can percolate down and be stored.

What are your expectations for the expedition?

– I hope we succeed in mapping where water is present, how much is stored and how it moves. It is difficult, cold and logistically challenging—but also a unique opportunity to collect data that no one has had before.

If everything goes according to plan, what data do you hope to bring back, and how can this contribute to the iQ2300 theme?

– We hope to collect:

• high-resolution radar profiles
• time series from our sensor masts
• firn cores and samples
• observations of the extent of melt layers

– With this, we can contribute to iQ2300 by:

• improving the modelling of meltwater in Antarctica
• better understanding the risk of hydrofracturing
• providing input for projections of future sea levels

– Understanding meltwater in Antarctica is like trying to see an entirely new hydrological system that is just beginning to emerge. It is invisible, complex and crucial for the future—and we are only at the beginning of understanding it, says Katrin Lindbäck.