Windstorm (Sturm)

Concept

In property insurance, windstorm refers to a weather-related air movement that reaches or exceeds a contractually defined minimum wind speed – policy conditions typically define windstorm as wind of at least force 8 on the Beaufort scale (roughly 62 km/h). Where the policyholder cannot demonstrate in an individual case that the relevant wind speed was actually reached, it is generally sufficient to show that comparable damage occurred to properly maintained objects in the immediate vicinity of the insured property.

Scope of Cover

Windstorm cover typically indemnifies losses caused directly by the action of the wind, such as roofs being stripped off, trees or masts being blown down, and damage caused to the insured property by objects carried or knocked down by the storm; windstorm cover typically also extends to consequential damage from rainwater entering the building, where this was caused directly by storm-related damage to the building.

Distinction and Accumulation Risk

Alongside hail, flood, and earthquake, windstorm is one of the core natural hazard perils and, in most jurisdictions, is either included as a standard peril in building and household contents insurance or can be additionally purchased as part of extended natural hazards cover; for insurers and reinsurers, windstorm represents a significant accumulation risk due to the wide geographic footprint of winter storms and hurricanes, and plays a central role in natural catastrophe modeling.