Posted on 21 February 2011 at 16:40h

Nice weather today, blue skies and -12 until the sun comes up. As the days grow longer the intensity of the sun becomes noticeably more. In this photo of my neighbours houses you can see that the amount of snow remaining on the roofs is related to the direction they are facing. All the roofs are the same angle and since the snow fell on a fairly windless night originally had the same amount of snow on them. The air temperature hasn't been above zero so the only way the snow can melt is by absorbing energy from the sun (houses are well insulated in Norway so very little heat escapes from the inside). The roof on the left is pointing directly South so gets most sun and the one in the middle is pointing North so gets no sun. The sticking out roof above the balcony points West. It would be very interesting to measure the thickness of snow on a whole range of roofs, roll on group 4 project day.