Devices such as that are sheared off as if they didn't exist. I have seen
the ribs of heavy gauge metal roofs folded over and flattened as the snow
creeps diagonally away from the valleys. We have had success with these
clips in low snow load areas.
From: Parkerres+AEA-aol.com +ADw-Parkerres+AEA-aol.com+AD4-
To: seaint+AEA-seaint.org +ADw-seaint+AEA-seaint.org+AD4-
Date: Friday, May 28, 1999 9:15 AM
Subject: Re: FALLING ICE
+AD4-You may try to install some icebreaker devices on the edge of the high roof
+AD4-to break up the snow as it falls. This is commonly done in locations where
+AD4-the falling snow/ice would not hit a low roof, but would land on someone's
+AD4-Bruce Resnick, SE
+AD4-Parker Resnick Str. Eng.
+AD4-In a message dated 5/27/99 11:21:41 PM Pacific Daylight Time,
+AD4- This topic is along the lines of a problem that I will soon have to
+AD4- Several months ago Kirkwood Ski resort called me to look at a roof that
+AD4- a failure. It seems that a large glacial like chunk of ice (rough guess
+AD4- tons) fell about 20 feet from an upper roof and shattered some rafters at
+AD4- the front of the general store. It turns out this is the second time that
+AD4- this has happened.
+AD4- A little aside, it seems that architects rarely listen to warnings
+AD4- explaining all the possible affects of sixty feet of annual snow fall.
+AD4- The lower roof was originally 3x6 rafters at 2' oc spanning about 5'. The
+AD4- first time they failed they replaced them with 4x6 at 2'oc. Five or six
+AD4- these 4x6's at the impact area were reduced to splinters. The snow load
+AD4- this area (Pf) is 300 psf, the funny part of the story is that this roof
+AD4- never has any snow on it. The upper roof tends to acculimate snow at an
+AD4- adjacent valley area and then gradually creep until it eventually falls to
+AD4- the unloaded roof below, then bounces off and lands in the parking lot. I
+AD4- gave Kirkwood a temporary repair last the winter, and told them to call me
+AD4- this summer for a permanent repair. I think that I will have fun trying
+AD4- come up with a reasonable but safe impact load for the new roof.
+AD4- Randy Vogelgesang S.E.
+AD4- South Lake Tahoe +AD4APg-