Bertel Vehviläinen from the Finnish Environment Institute says that the biggest risks are faced by large halls and warehouses with flat roofs. The depth of snow on roofs can measure as much as double that on the ground, weighing up to 180 kilos per square metre. Last year tens of buildings collapsed as a result of an excess of snow on the roof. All of these buildings were found to have been structurally unsound.
Vehvilainen does not know of any cases where private houses have collapsed for this reason.
"My own view is that once the snow has reached a metre in depth, then it is time to have it removed. The risk for householders is that in doing that they will be injured by falling to the ground."
