Impact of hail events on agriculture: A remote sensing-based analysis of hail damage in the context of climate change

In the project HAGL (“Impact of hail events on agriculture: A remote sensing-based analysis of hail damage in the context of climate change”), we analyse the effects of hail damage on agriculture. In the context of climate change and the associated increased risk of extreme weather events to society and the economy, this project deals with a locally catastrophic natural hazard that causes high costs, namely hail. Hail, combined with severe storms, causes millions of Euros of damage to agriculture every year. The influence of climate change on local weather patterns (e.g. thunderstorms) is still relatively unexplored, but early evidence points to an increase in weather patterns causing hail and an increase in hailstone sizes. In Austria, especially southeastern Styria with its various crops is frequently affected by extreme hail events. Yield losses due to hail damage can be existence-threatening for farmers, which is why an effective damage assessment is of great interest.

We aim to develop an efficient method to determine the damage to agriculture caused by hail using various remote sensing data. Through a spatial hotspot analysis, we identify regions in southeastern Styria that are particularly affected by hailstorms to test and validate our method. We perform a combined analysis of Sentinel-2 optical and Sentinel-1 synthetic aperture radar (SAR) data using object-based image analysis (OBIA) methods and different vegetation indices derived from the multispectral data as well as radar backscatter signals to detect hail damage. Finally, we aim to create a damage categorisation that could support insurance work in the event of a disaster and make it more efficient by providing a first estimation of the damage before an on-side assessment is conducted. Especially for large agricultural fields, this would save time and resources by making it possible to prioritise areas with high damage and organise the fieldwork of insurance employees accordingly.