Slab avalanche ... in my driveway

[sardog1]

Here's an object lesson in snow mechanics, from my own driveway after the recent storm:

Homegrown slab avalanche

This slab demonstrates very nicely the mechanism of slab avalanches. Note how the roof angle, like that of some mountainsides, is perfectly suited for snow accumulation - to a point. Note the cohesiveness of the slab, even to the point of sliding to the left because the trailer leans that way. Note the ease with which it slides on the surface under it, to which it is very poorly bonded. Finally, note the fracture line of a "natural" avalanche that has already occurred.

 

[Kevin Rooney]

You may need your transponder to get to the mailbox ...

 

[peakbagger]

My Pole Mounted Solar Panels exhibit similar characteristics. To make it more interesting, I can vary the angle of tilt but despite it being spring, they are still tilted down at winter angle of 30 degrees off vertical to cut down on accumulation.

 

[RoySwkr]

yeah, watched a similar thing happen slowly on the trunk of my car involving a number of angles and fractures

 

[TCD]

My old house with a slate roof used to avy all the time. If you were upstairs the roar would surprise you. If you were outside, you could actually hear the snow "crack" or "pop" when the fracture released. All sorts of exotic looking textbook fracture lines on the roof. Very neat stuff.

 

[sardog1]

My old house with a slate roof used to avy all the time. If you were upstairs the roar would surprise you. If you were outside, you could actually hear the snow "crack" or "pop" when the fracture released. All sorts of exotic looking textbook fracture lines on the roof. Very neat stuff.

Sadly, there are fatalities now and then from these. There was one in a nearby town the year I arrived in NH, and I know of cases from AK and MN. Some examples are collected here: [url]http://tinyurl.com/cqnbc5e[/URL]

 

[David Metsky]

My old house with a slate roof used to avy all the time.

Mine too, usually right after I had just finished shoveling the driveway.

 

[skiguy]

I have a Steel roof on my house. You could conduct an international symposium on avalanches here if you wanted. All inclusive with different pitch angles, valleys, and deposition zones.

 

[Stan]

We have a copper roof over our screened in porch, about a 3 in 12 pitch which I comfortably climb in ordinary workboots without rope or harness ... all the while fantasizing some far off mountain. It has had some terrific avalanches, even shaking the whole house! ... but the main fractures occur to the screens themselves which I'm reluctant to repair until thoroughly convinced that sufficient copper oxidization has occurred to provide friction to prevent the slide. Old roofers told me the best way to expedite oxidation is with horse piss but they could never figure out a way to get the horse on the roof.

That avalanche is nothing compared to the glacier that's forming on some shady stairs down to the driveway.

Nature can work in our interest, however. By careful calibration, I have installed optimal attic insulation to provide the precise roof snow melt to form icicles which conveniently hang all the way to the ground, making them easy to harvest in event of a power outage that prevents making ice cubes for the bourbon.