Identification of Warning Fatigue and Its Impact on Municipal Preparedness in Norway

From 7. August 2023 to 9. August 2023, Norway was hit by the extreme weather event “Hans”. Especially in the southern and western parts of the country, municipalities were warned about precipitation of up to 100 mm within 24 hours (Norwegian Meteorological Institute, 2023) causing extensive flooding and landslides. Rain, flood and landslides warnings were issued early and for large areas. Not all municipalities reacted with the necessary urgency to the situation for various reasons. In a survey of the affected municipalities after “Hans”, many municipalities described that they were overwhelmed with the circumstances or had no prior experience with the size of the predicted floodings. On the other hand, there were municipalities that had experienced major floodings before, but underestimated the severity of “Hans”. The general opinion of Norwegian municipalities is that there are too many warnings, leading to warning fatigue. Hence, this study aims to: i) analyse the total number of issued warnings, as well as the warning level assigned, and ii) analyse the warning response of selected municipalities before and after “Hans”.

Through a statistical review of all municipalities’ warnings, clusters of municipalities prone to warning fatigue, or under-preparedness are found. By comparing the response to different extreme weather events, the goal is to identify patterns resulting in over-warning or warning fatigue. It is expected that the number of issued warnings, will have increased over the last ten years, however cross-referencing with the preparedness to future events by installing mitigation measures, citizen education on natural hazards and such, differences between municipalities will become apparent.