Weather-Related Flood and Landslide Damage: A Risk Index for Italian Regions

Abstract

The frequency of natural hazards has been increasing in the last decades in Europe and specifically in Mediterranean regions due to climate change. For example heavy precipitation events can lead to disasters through the interaction with exposed and vulnerable people and natural systems. It is therefore necessary a prevention planning to preserve human health and to reduce economic losses. Prevention should mainly be carried out with more adequate land management, also supported by the development of an appropriate risk prediction tool based on weather forecasts. The main aim of this study is to investigate the relationship between weather types (WTs) and the frequency of floods and landslides that have caused damage to properties, personal injuries, or deaths in the Italian regions over recent decades. In particular, a specific risk index (WT-FLARI) for each WT was developed at national and regional scale. This study has identified a specific risk index associated with each weather type, calibrated for each Italian region and applicable to both annual and seasonal levels. The risk index represents the seasonal and annual vulnerability of each Italian region and indicates that additional preventive actions are necessary for some regions. The results of this study represent a good starting point towards the development of a tool to support policy-makers, local authorities and health agencies in planning actions, mainly in the medium to long term, aimed at the weather damage reduction that represents an important issue of the World Meteorological Organization mission.

Fig 1. 500hPa geopotential height for each weather types (WT) classified by LAMMA-IBIMET for the period 1948–2011.

Fig 2. Work-flow of the Weather Type-related Floods and Landslides Risk Index (WT-FLARI) assessment.

Fig 3. Incidence of normalized features for each Italian region.

Fig 4. Mapping of the annual WT-related Floods and LAndslides Risk Index (WT-FLARI).

WT (Weather Type). WT-FLARI levels: red = Very High (WT-FLARI > 99^th perc.); orange = High (95^th perc. > WT-FLARI > 99^th perc.); yellow = Moderate (95^th perc. > WT-FLARI > 90^th perc.); white = Low (WT-FLARI < 90^th perc.)

Fig 5. Mapping of the autumn WT-related Floods and LAndslides Risk Index (WT-FLARI).

WT (Weather Type). WT-FLARI levels: red = Very High (WT-FLARI > 99^th perc.); orange = High (95^th perc. > WT-FLARI > 99^th perc.); yellow = Moderate (95^th perc. > WT-FLARI > 90^th perc.); white = Low (WT-FLARI < 90^th perc.)

Fig 6. Mapping of the spring WT-related Floods and LAndslides Risk Index (WT-FLARI).

WT (Weather Type). WT-FLARI levels: red = Very High (WT-FLARI > 99^th perc.); orange = High (95^th perc. > WT-FLARI > 99^th perc.); yellow = Moderate (95^th perc. > WT-FLARI > 90^th perc.); white = Low (WT-FLARI < 90^th perc.)

Fig 7. Mapping of the winter WT-related Floods and LAndslides Risk Index (WT-FLARI).

WT (Weather Type). WT-FLARI levels: red = Very High (WT-FLARI > 99^th perc.); orange = High (95^th perc. > WT-FLARI > 99^th perc.); yellow = Moderate (95^th perc. > WT-FLARI > 90^th perc.); white = Low (WT-FLARI < 90^th perc.)