The eastern side of the Antarctic Peninsula (AP) mountain range and the adjacent ice shelves are frequently affected by föhn winds originating from upwind of the mountains. Six automatic weather stations (AWSs) and archived model output from 5 km resolution Antarctic Mesoscale Prediction System (AMPS) forecasts have been combined to identify the occurrence of föhn conditions, and their spatial distribution over the Larsen C Ice Shelf (LCIS) from 2009 to 2012. Algorithms for semi‐automatic detection of föhn conditions have been developed for both AWS and AMPS data. The frequency of föhn varies by location, being most frequent at the foot of the AP and in the north of the ice shelf. They are most common in spring, when they can prevail for 50% of the time. The results of this study have important implications for further research, investigating the impact of föhn on surface melting, and the surface energy budget of the ice shelf. This is of particular interest due to the collapse of Larsen A and B ice shelves in 1995 and 2002 respectively, and the potential instability issues following a large calving event on Larsen C in 2017.

The disintegration of the ice shelves along the Antarctic Peninsula have spurred much discussion on the various processes leading to their eventual dramatic collapse, but without a consensus on an atmospheric forcing that could connect these processes. Here, using an atmospheric river detection algorithm along with a regional climate model and satellite observations, we show that the most intense atmospheric rivers induce extremes in temperature, surface melt, sea-ice disintegration, or large swells that destabilize the ice shelves with 40% probability. This was observed during the collapses of the Larsen A and B ice shelves during the summers of 1995 and 2002 respectively. Overall, 60% of calving events from 2000–2020 were triggered by atmospheric rivers. The loss of the buttressing effect from these ice shelves leads to further continental ice loss and subsequent sea-level rise. Under future warming projections, the Larsen C ice shelf will be at-risk from the same processes.

The ice shelves on the east coast of the Antarctic Peninsula (AP) have been disintegrating for over two decades. Surface melting induced by föhn winds has been proposed as a driver of this disintegration. Föhn winds are adiabatically warmed dry winds, formed by the interaction of a mountain range with perpendicularly approaching winds, in this case of the AP mountains with the prevailing circumpolar westerlies. Assessing their impact is difficult due to the sparsity of observations and the relatively low‐resolution of operational forecasts. We have carried out high‐resolution simulations using the Weather Research and Forecasting (WRF) model to provide more detailed simulations of the spatial distribution of the föhn air. The analysis presented here covers the period from 10 to 22 May 2011 and focuses on two föhn events during this period. Results show that a stable boundary layer can reduce the impact of föhn, as can the occurrence of cooler föhn jets.