Qu'est-ce que c'est?

This is picture is somewhat relevant to the story....
I received a rude wakeup at 5 am a few days ago, when it sounded like a team of construction workers had descended onto the house from a helicopter. Well that might be exaggerating a little, but at 5am it was LOUD (and dark). I may have mentioned before that I live approximately 500 meters from a psychiatric hospital, where Norway likes to send their finest insane criminals. This tends to cause me some jumpiness at 5am. I live on the 2nd floor of the house, but generally in the winter I am too lazy to go down and lock the outside door to the stairwell, because well I'm lazy, I don't want to get my feet cold and my fleecy slippers fall off going down stairs. So I normally just lock the upper door into the apartment and go to bed. This was one of those nights. So my first thought after jumping out of bed was that an escaped prisoner was trying to hack his way into the house. So I ran into the hallway and sure enough, I could see that the motion sensing light in the stairwell was on. Now being it is 5am, I just woke up and I'm not really that smart anyway, I OPENED THE DOOR, to see who was in there. Fortunately for me, I did not receive an ax into the forehead. I didn't see anyone, but I heard something... which sounded suspiciously like a crazy person talking to themselves. I ran over to the small north window that looks towards the driveway into the garage. I see a shadow! Someone is walking alongside the house and mumbling. I've got you now serial killer, I thought. I ran over to the kitchen window facing the street to try to get a glimpse of the psycho as he came around the corner.
-and-
OK, it was the guy delivering the newspapers, singing along with his ipod. whew.
That didn't really explain all the noise until I went back over to the south windows, where I could see that the section of roof from this picture was now bare. The entire load of ice and snow had slid off at once. Since the roof is tiled, every time the ice bumped over a tile it shook the crap out of the house, waking me up and setting off the motion sensor. Mystery solved, although somehow that did not really help me go back to sleep. Next I will start working on that remote locking mechanism for the outside door....