Known Issue 316

For exposures with an unknown number of stories, losses produced by the Verisk Inland Flood Model for Central Europe exhibit a systematic over- or under-estimation depending on the modeled country.

Issue ID	316
Summary	For exposures with an unknown number of stories, losses produced by the Verisk Inland Flood Model for Central Europe exhibit a systematic over- or under-estimation depending on the modeled country.
Description	With the 2019 update of the Verisk Inland Flood Model for Central Europe, a change was introduced to better differentiate building height-dependent vulnerability – within the low-rise category the model differentiates now between 1-, 2-, and 3-story buildings. The vulnerability functions for unknown-story height are based on weighted averages of the individual vulnerability functions for 1-,2-, and 3-stories, as well as for mid- and high-rise. Verisk reviewed the "unknown" vulnerabilities and discovered a mismatch  in the definition of number of stories between the model and the datasets used to inform the model regarding the assumed building height distributions for low rise buildings. These discrepancies result in an overestimation of losses when the number of stories is not defined by the user in the countries of Austria, the Czech Republic, Germany and Poland and an underestimation of loss in Switzerland.
Resolved in
Date posted	2/4/2021
Software versions affected	10.0
Feature set	Detailed loss
Models	Verisk Inland Flood Model for Central Europe
Potential for loss numbers impact	No
Workaround	Verisk will provide a permanent fix in the model in Release 2021 and can provide Loss Modification Templates as an interim workaround. Contact your Verisk representative for more information. Until then clients are advised to either use the workaround or specify the number of stories in the exposure – defined as the number of furnished stories above ground.