Snow and ice on roofs – icicles and climate change

Icicles generation on roofs is a problem in the winter period. People have been killed from falling icicles because they have not been taken away before the size is too large. Building a model to predict, when we have a risk for generation of icicles is very interesting. The problem with icing and icicles on roof is a complex problem involving architecture, meteorology, glaciology and building physics. The architect decides the layout of the building and the form of roof used. The architectural solution can reduce or increase the risk of icicle generation. The meteorology comes in, as we must know the weather that will permit the icicles formation. The glaciology has the information on the physics behind ice and snow. The building physic is involved as heat air and moisture transfer is involved. The paper presents an expanded model (first version presented at the Building Physics symposium in Reykjavik 2005) for generation of icicles. We know that climate change will affect the future climate. SMHI has made climate senarios until 2100. Based on this I will try to give a first estimate on the future risk for icicle falls. A discussion on risks and how to aviod the problem will be given.