The peak gust risk assesses how often the site is hit by gusts strong enough to cause damage (at least 90 km/h). It is estimated from the maximum gust of each year from 1940 to today: the more often such a gust comes back, the higher the risk. The class is the same in every scenario, because climate models do not simulate gusts reliably.
Indicator. Return period, in years, of a gust of at least 25 m/s (90 km/h), the speed at which damage starts according to Roberts et al. 2014. The 50-year gust and the maximum observed gust are also reported.
Data. Daily maximum 10 m wind gust (3-second gust) of the ERA5 reanalysis (Hersbach et al. 2020) from 1940 to 2025, through the Open-Meteo archive (ERA5 only, not the default blend with other models); one maximum per year, only for years with at least 330 valid days. Scenarios: SSP1-2.6 / SSP2-4.5 / SSP3-7.0 / SSP5-8.5, with the same class.
Calculation.
(1) For each year from 1940 to 2025 the maximum gust is taken.
(2) A GEV (Generalized Extreme Value) distribution is fitted to the yearly maxima, as for the 50-year wind of Eurocode EN 1991-1-4.
(3) The return period is the inverse of the annual probability of exceeding 90 km/h; the 50-year gust is the value exceeded with a 2% probability per year.
(4) The class is the same in every scenario and year: IPCC AR6 (WGI, chapter 12) states that gust projections are not available because climate models do not simulate them.
Note: ERA5 underestimates tropical cyclone winds (Hodges et al. 2017) and strong gusts at coastal and mountain stations (Minola et al. 2020), so at exposed sites the risk may be underestimated.
Thresholds → level A–F.
• 90 km/h at least once every 3.2 years → F
• every 3.2–10 years → E
• every 10–22.4 years → D
• every 22.4–50 years → C
• every 50–1,000 years → B
• less than once every 1,000 years → A.
ThinkHazard! bands (GFDRR): high hazard within 10 years, medium within 50, low within 1,000, translated as for landslides (high → E/F, medium → C/D, low → B, beyond → A); within the high and medium bands the more frequent half (split at the geometric middle: 3.2 and 22.4 years) takes the higher class, a xNatura choice.
From physical to impact. The physical level (A–F) is combined with the production process's sensitivity through the risk matrix (6 physical levels by 5 sensitivity bands) → impact level. The euro amount of this risk is the one described in the "Economic damage" paragraph (Version 2026): the damage factor per class of Version 2025 is no longer used for this risk.
Economic damage. Besides the class, the loss in euro is estimated as a share of the asset value (building only, no contents), with the FEMA Hazus hurricane damage curves (version 5.1), calibrated on United States buildings: the share of the building value lost at each gust, in open terrain.
• The site's structure type picks the curve: light steel = pre-engineered steel building; steel, concrete, precast concrete and reinforced masonry = low-rise engineered commercial buildings; masonry = masonry industrial building. Basis: published source. For wood (Hazus has no wooden industrial or commercial buildings) or without a type, the mean of the six structures is used: basis "xNatura estimate".
• The curve is applied to the same GEV distribution of gusts used for the class: expected annual loss (mean of the loss over the distribution of the yearly maximum gust, up to the 10,000-year gust) and loss at the gust that comes back once in 100 years. Same values in every scenario: gust projections are not reliable.
Simplifications: ERA5 cell gusts, not measured in open terrain (they underestimate cyclones and exposed stations); replacement cost equal to the book value; one building type per site.
Sources.
• [Roberts et al. 2014, The XWS catalogue of European windstorms](Roberts et al. 2014, The XWS catalogue of European windstorms)
• [ThinkHazard! methodology report (GFDRR)](ThinkHazard! methodology report (GFDRR))
• [Eurocode EN 1991-1-4, wind actions](Eurocode EN 1991-1-4, wind actions)
• [Bloemendaal et al. 2020, STORM tropical cyclone return periods](Bloemendaal et al. 2020, STORM tropical cyclone return periods)
• [IPCC AR6 WGI, Chapter 12: Climate Change Information for Regional Impact and for Risk Assessment](IPCC AR6 WGI, Chapter 12: Climate Change Information for Regional Impact and for Risk Assessment)
• [Hersbach et al. 2020, The ERA5 global reanalysis](Hersbach et al. 2020, The ERA5 global reanalysis)
• [Hodges et al. 2017, tropical cyclones in reanalyses](Hodges et al. 2017, tropical cyclones in reanalyses)
• [Minola et al. 2020, ERA5 gusts against station observations](Minola et al. 2020, ERA5 gusts against station observations)
• [FEMA Hazus Hurricane Model Technical Manual 5.1](FEMA Hazus Hurricane Model Technical Manual 5.1)
• [NHERI SimCenter Damage and Loss Model Library, Hazus hurricane loss functions](NHERI SimCenter Damage and Loss Model Library, Hazus hurricane loss functions).
Indicator. Return period, in years, of a gust of at least 25 m/s (90 km/h), the speed at which damage starts according to Roberts et al. 2014. The 50-year gust and the maximum observed gust are also reported.
Data. Daily maximum 10 m wind gust (3-second gust) of the ERA5 reanalysis (Hersbach et al. 2020) from 1940 to 2025, through the Open-Meteo archive (ERA5 only, not the default blend with other models); one maximum per year, only for years with at least 330 valid days. Scenarios: SSP1-2.6 / SSP2-4.5 / SSP3-7.0 / SSP5-8.5, with the same class.
Calculation.
(1) For each year from 1940 to 2025 the maximum gust is taken.
(2) A GEV (Generalized Extreme Value) distribution is fitted to the yearly maxima, as for the 50-year wind of Eurocode EN 1991-1-4.
(3) The return period is the inverse of the annual probability of exceeding 90 km/h; the 50-year gust is the value exceeded with a 2% probability per year.
(4) The class is the same in every scenario and year: IPCC AR6 (WGI, chapter 12) states that gust projections are not available because climate models do not simulate them.
Note: ERA5 underestimates tropical cyclone winds (Hodges et al. 2017) and strong gusts at coastal and mountain stations (Minola et al. 2020), so at exposed sites the risk may be underestimated.
Thresholds → level A–F.
• 90 km/h at least once every 3.2 years → F
• every 3.2–10 years → E
• every 10–22.4 years → D
• every 22.4–50 years → C
• every 50–1,000 years → B
• less than once every 1,000 years → A.
ThinkHazard! bands (GFDRR): high hazard within 10 years, medium within 50, low within 1,000, translated as for landslides (high → E/F, medium → C/D, low → B, beyond → A); within the high and medium bands the more frequent half (split at the geometric middle: 3.2 and 22.4 years) takes the higher class, a xNatura choice.
From physical to impact. The physical level (A–F) is combined with the production process's sensitivity through the risk matrix (6 physical levels by 5 sensitivity bands) → impact level. The euro amount of this risk is the one described in the "Economic damage" paragraph (Version 2026): the damage factor per class of Version 2025 is no longer used for this risk.
Economic damage. Besides the class, the loss in euro is estimated as a share of the asset value (building only, no contents), with the FEMA Hazus hurricane damage curves (version 5.1), calibrated on United States buildings: the share of the building value lost at each gust, in open terrain.
• The site's structure type picks the curve: light steel = pre-engineered steel building; steel, concrete, precast concrete and reinforced masonry = low-rise engineered commercial buildings; masonry = masonry industrial building. Basis: published source. For wood (Hazus has no wooden industrial or commercial buildings) or without a type, the mean of the six structures is used: basis "xNatura estimate".
• The curve is applied to the same GEV distribution of gusts used for the class: expected annual loss (mean of the loss over the distribution of the yearly maximum gust, up to the 10,000-year gust) and loss at the gust that comes back once in 100 years. Same values in every scenario: gust projections are not reliable.
Simplifications: ERA5 cell gusts, not measured in open terrain (they underestimate cyclones and exposed stations); replacement cost equal to the book value; one building type per site.
Sources.
• [Roberts et al. 2014, The XWS catalogue of European windstorms](Roberts et al. 2014, The XWS catalogue of European windstorms)
• [ThinkHazard! methodology report (GFDRR)](ThinkHazard! methodology report (GFDRR))
• [Eurocode EN 1991-1-4, wind actions](Eurocode EN 1991-1-4, wind actions)
• [Bloemendaal et al. 2020, STORM tropical cyclone return periods](Bloemendaal et al. 2020, STORM tropical cyclone return periods)
• [IPCC AR6 WGI, Chapter 12: Climate Change Information for Regional Impact and for Risk Assessment](IPCC AR6 WGI, Chapter 12: Climate Change Information for Regional Impact and for Risk Assessment)
• [Hersbach et al. 2020, The ERA5 global reanalysis](Hersbach et al. 2020, The ERA5 global reanalysis)
• [Hodges et al. 2017, tropical cyclones in reanalyses](Hodges et al. 2017, tropical cyclones in reanalyses)
• [Minola et al. 2020, ERA5 gusts against station observations](Minola et al. 2020, ERA5 gusts against station observations)
• [FEMA Hazus Hurricane Model Technical Manual 5.1](FEMA Hazus Hurricane Model Technical Manual 5.1)
• [NHERI SimCenter Damage and Loss Model Library, Hazus hurricane loss functions](NHERI SimCenter Damage and Loss Model Library, Hazus hurricane loss functions).