News 16.12.2020

Numerical weather model predicts iciness of footpaths

A numerical weather model developed at the Finnish Meteorological Institute is used to predict the iciness of footpaths under different weather conditions. Forecasts made by the model are used in the weather service when it issues warnings about slippery pavement.
Photo: Juha Tuomi

The Finnish Meteorological Institute issues warnings about slippery pavements. From a pedestrian's point of view, slippery conditions prevail particularly when there is water or loose snow on top of a layer of ice on the surface of a road. Freshly fallen snow can also become very slippery when it is pressed down in certain conditions if many people walk on it. No observational measurements are available on the degree of slipperiness of footpaths, so the pedestrian model serves as an essential tool for meteorologists on duty in evaluating slipperiness. In addition to the traditional warning map, the Finnish Meteorological Institute has an iciness warning service for companies and municipalities. A municipality can buy the service for its residents, or employers can get it for their employees.

The pedestrian slippery index model has been developed by the Finnish Meteorological Institute from the road weather model. A fresh study presents statistics on accidents involving slipping, and on the physical principle of the pedestrian model as well as examples of slippery conditions.

More information:

Researcher Marjo Hippi, Finnish Meteorological Institute, tel. 029 539 3153,

Hippi M, Kangas M, Ruuhela R, Ruotsalainen J, Hartonen S., RoadSurf-Pedestrian: a sidewalk condition model to predict risk for wintertime slipping injuries. Meteorol Appl.2020;27:e1955.

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