Meteorological factors control landslide phenomena in a high-Arctic glacier basin (Ny-Ålesund, Svalbard)

Landslide activity is expected to increase as climate change reduces mountain slope stability. High-Arctic regions like Svalbard are critical for studying slope dynamics in a changing climate, especially due to arctic amplification effects. Despite the significance of Arctic regions for climate research, empirical evidence in these regions is often lacking due to the absence of long-term, high-resolution terrain data necessary to assess the impact of meteorological conditions on landscapes severely affected by climate change. Bridging this gap is vital for comprehending the intricate relationships between meteorological factors and landslide development in Arctic regions.

This study presents a unique high-resolution on-site dataset from a high-Arctic glacier basin, collected over a 10-year period. Using terrestrial laser-scanning and an autonomous camera network, we investigated the impact of meteorological conditions on the trigger mechanisms of translational debris slides and debris flows in the Austre Lovénbreen glacier basin (Svalbard, Norway).

Translational debris slides accounted for approximately 96% (N = 147) of the total sediment flux observed, with debris flows (N = 21) as a secondary agent. Debris slide activity significantly increased between 2011 and 2021. Heavy rainfall events primarily influenced the frequency and magnitude of debris slides during the hydrological summer, while the duration and intensity of the thawing period were the main controls for their initiation. On the opposite, the impact of winter temperatures or snow parameters was limited. Furthermore, a 2-year return period for large debris flows was identified, representing an increase by a factor of 2.5 to 5 compared to previous estimates for Svalbard and northern Scandinavia in the last decades.

In conclusion, this study highlights the significant impact of meteorological factors on the frequency and magnitude of landslides in high-Arctic glacier basins, providing insights into how climate change controls landslide dynamics in Arctic environments. The expected continuous rise in temperatures and increased heavy rainfall events are likely to further facilitate landslide activity in the Arctic.

Thus, this study shows that long-term observatories like the Austre Lovénbreen glacier are irreplaceable for future research unraveling the impact of climate change on landslide dynamics and that the present climate alterations in the Arctic may provide insights also relevant for other regions.