Annelies Voordendag receives L’Oréal-UNESCO Award
Annelies Voordendag, a postdoctoral researcher at ETH Zurich’s Department of Civil, Environmental and Geomatic Engineering, has been named one of four laureates of the Swiss L'Oréal-UNESCO "For Women in Science" Awards 2025. The programme honours outstanding female scientists for their contributions to research and society.
Annelies Voordendag is recognised for developing a new method to observe glaciers. Her approach combines surveying techniques with glacier science to track how ice moves and melts over time in high detail. In her project, the researcher uses specially designed reflective markers – nicknamed "ice lollipops" – that can be detected in long-range terrestrial laser scanning data and withstand extreme alpine conditions.
This detailed tracking also helps scientists better understand how much ice a glacier gains or loses over time – a measure known as glacier mass balance. Under the guidance of Professor Andreas Wieser, Head of the Geosensors and Engineering Geodesy group, Voordendag uses the data to monitor glacier mass balance at high temporal resolution without frequent field visits. "By combining precise measurement tools with knowledge about glaciers, we can better understand how they respond to climate change", she explains.
Her system was first tested with one ice lollipop on the Hintereisferner glacier in the Austrian Alps. There, she set up a permanent terrestrial laser scanner system that automatically collects long-term data. The L'Oréal-UNESCO award, endowed with 25,000 CHF, will help her to perform new fieldwork campaigns with a network of ice lollipops.
Beyond her scientific work, Voordendag is a committed advocate for gender equity in STEM. As a long-time mentor with Girls on Ice Austria, she encourages young women to explore science through hands-on field experiences. "Coming from a small Dutch farm, I want to show that anyone can contribute to science," the postdoctoral researcher says.
Her interest in snow and mountains began during family skiing holidays, shaping both her personal and professional path. For more than 13 years, she has spent her academic breaks working as a ski and snowboard instructor, skills that now prove invaluable in her glacier fieldwork. "People often say, ‘You ski really well – for a Dutch person'", she says with a smile.
Annelies Voordendag
Annelies Voordendag holds degrees in Applied Earth Sciences and in Science Education and Communication from TU Delft, as well as a doctorate in Atmospheric Sciences from the University of Innsbruck. Since 2023, she has been a postdoctoral researcher at ETH Zurich, where she contributes to the development of geodetic methods for environmental monitoring. In 2024, she received the CCCA Nachwuchspreis for her work on Glacier Loss Day, a project that raises awareness of glacier retreat.