Snow removal from roofs causes fatal accidents

Expert recommends that snow should be cleared only with professional help

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In a number of accidents involving people who were clearing snow off their roofs, at least three people died at the weekend.
      In Kouvola in Southeastern Finland, a man in his 50s died when he was removing snow from the roof of his house on Sunday and he fell to the ground. The avalanching masses of snow coming off the roof buried him.
      In Leppävirta in North Savo, another man was shovelling snow on Saturday, when he fell off the roof of his house and died.
      On Saturday, a 60-year-old man died in Asikkala near Lahti , when a 40-cm snow load covering several square metres fell down over him from the roof of a row house.
     
Moreover, the media reported on Sunday on dozens of snow shovellers who had fallen off roofs in Helsinki and in other parts of Finland.
     
Chief hydrologist Bertel Vehviläinen from the Finnish Environment Institute recommends that professional help should always be used to remove snow from roofs.
      According to Vehviläinen, at present heavy snow is causing dangerous situations everywhere.
      ”One risk exists if one leaves the snow on the roof and another if one goes to the roof in order to clear it of snow, which is why snow removal should be left in the hands of professionals”, Vehviläinen notes.
     
In an interview with the Finnish Broadcasting Company (YLE) on Sunday, Minister of Housing Jan Vapaavuori (National Coalition Party) defended his earlier call to people to clear snow from the roofs of their houses.
      He said that the officials had specially emphasised that when shovelling snow off the roof people should use proper safety meeasures.
      However, Bertel Vehviläinen criticised that the calls of officials for people to remove snow from their roofs led to the wrong outcome.
      ”After having been informed in good faith of a risk of collapse, even such people took to the roofs who should never have done so. The message should have stressed more the fact that the owners of detached houses must not go onto the roof without any safety equipment”, Vehviläinen points out.
     
According to Vehviläinen, the weight of the snow load on roofs exceeds the roofs’ snow-bearing capacity in many places, particularly in Southern Finland and along the southern coast.
      In the current week, the structural strength of roofs may be tested even in Eastern Finland and in Ostrobothnia, if further snowfalls occur.
      Detached houses or row houses are normally not at risk of collapsing.
      ”The actual problem appears to be the risk of falling off the roof. I do not know of any cases in which a detached house or a row house would have collapsed because of the weight of the snow on the roof. Even though the roof’s snow-bearing capacity is exceeded, small buildings do not easily collapse”, Vehviläinen argues.
      On Saturday, a porch of a detached house in Helsinki collapsed - apparently as a result of an exceptional snow load.
     
At present, large buildings - including sports arenas, cattle sheds, and shopping malls - pose the greatest problem.
      ”All municipalities will have to have snow cleared from the roofs of large buildings”, says Vehviläinen.
      On Saturday, a Citymarket supermarket in Helsinki’s Itäkeskus shopping centre was evacuated because it was believed to be at risk of collapse. On Wednesday last week, the roof of a sports arena in Järvenpää, north of Helsinki, collapsed, injuring two people.
      While shovelling snow on Sunday, hydrologist Vehviläinen evaluated the weight of the snow on the roof of his own house. The snow was some 80 centimetres deep, and the weight of the snow was 215 kg/sqm.
      The weight came as a surprise to the hydrologist.
      ”This is above the snow-bearing capacity of most of the newest roofs, but in practice, detached houses and row houses can bear more than these norms indicate”, Vehviläinen adds.


Previously in HS International Edition:
  Snow load on roofs getting risky in places (24.2.2010)
  Finnish Meteorological Institute: Weather this severe 40 years ago (24.2.2010)

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