Environment Institute warns of dangers of dropping snow from roofs

“Leave it to the professionals”, experts say

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Hydrologist Bertel Vehviläinen of the Finnish Environment Institute is warning home-owners against venturing onto the roofs of houses to remove the considerable build-up of snow, which is now growing heavier as the weather warms up.
      “Not a single detached house, row house, or properly-built summer cottage has ever collapsed under the weight of snow”, Vehviläinen says.
      “Small houses are not risky because of any danger of collapse, but rather because people go on the roofs to work with the snow and then fall off.”
     
Vehviläinen emphasises that knocking snow off roofs requires skill.
      “That is why people should not climb onto the roofs at all. At least people should not go there who do so once in a lifetime, or once every ten years. As an official I can only say that the professionals should be called in.”
     
Those who insist on climbing onto a roof in spite of the warnings, should at the very least always remember to have a rope and a security harness, he says.
      Even those precautions will not necessarily save a beginner. A person climbing onto a roof in the present conditions could get hit by an avalanche of two tonnes of snow at the slightest jolt.
      Houses with flat roofs are not quite as dangerous.
     
As a rule, snow should be removed from a roof when there is more than a metre of it.
      A layer of snow that is one metre thick weighs about 200 kilos per square metre.
      However, Vehviläinen says that a well-built roof will withstand much more weight than that.
      “Hardware stores sell various snow-dropping devices which make it possible to drop snow from the crest of a roof, or even from the ground with the help of a long pole, but they are still dangerous”, Vehviläinen points out.


Previously in HS International Edition:
  Helsinki is drowning in snow - Sunday pushed the capital deeper into the white mire (20.2.2012)
  Watch out for icicles as the weather warms up (21.2.2012)
  Snow removal equipment straining to cope with massive snowfall in Helsinki region (22.2.2012)

See also:
  Snow removal can be a wild wild business (25.1.2011)
  Heads up! Melting and falling snow makes Helsinki dangerous (11.1.2011)
  Snow removal from roofs causes fatal accidents (1.3.2010)

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