… an unexpected disaster?
The wildfires in California are a dramatic reminder of how severe the impact of natural hazards can be on society, the economy and the environment. Around Los Angeles, strong winds are driving at least five major fires – the consequences so far have been devastating: at least ten people have lost their lives, around 10,000 buildings have been destroyed and around 130,000 people have been displaced (source: Tagesschau from 10.01.2025).
However, the fires not only destroy infrastructure and living spaces. They also illustrate how unpredictable natural hazards are becoming in combination with climate change and human influence. But how can such dangers and risks be identified at an early stage?
The K.A.R.L. team is working intensively on this question and would like to use the current fires in California to show how our analysis can contribute to the assessment of forest fire hazards.
The occurrence of forest fires is largely dependent on the climatological conditions and the amount of combustible vegetation at the respective location. For the climatological conditions, we have developed an index (= climatological forest fire potential) that takes into account various climatic factors such as temperature, dryness and wind strength – all elements that can favor the development of fires. In addition, we have created a combustibility index for the vegetation components, which is based on land use data and is divided into different levels depending on the proportion of combustible material in the surrounding area. The risk of forest fires is highest when these two indices come together: a high climatic forest fire potential and a high combustibility index.
This approach can be illustrated using the example of the currently raging “Eaton Fires” near Pasadena: here, the high climatic forest fire potential meets the dense forest cover of the San Gabriel Mountains – a scenario that can be clearly seen in our analysis: