Jordan wrote:Shoveling, it felt like in the 15-20lb range..there were 4" of semi-solid ice crust followed by less dense stuff...about 20" high. Id say the garage is like 40' x 15'? So what is that like 7-8 tons?
Okay, water weighs 5.3 lbs/ ft^2 inch.
Fresh snow density varies from .10 for fresh "powder" snow to .35-.40 for "Cascade Concrete". As it settles, density rises, and a typical settled winter snow pack is in the .30-.35 range. Ice approaches a density of .92. We'll round up to 1 for this excercise and use a typical .33 for the older snow. When snow is "ripe" (beginning to melt and liquid water running out), it's typically .45.
You have a 600 ft^2 roof.
4" ice = 1 x 4 x 600 x 5.3 = 12720 lbs for the ice.
20" snow = .33 x 20 x 600 x 5.3 = 20988 for the snow.
(12720 + 20988)/ 2000lbs/ton = 16.8 Tons (
) or 540 ft^3 of water!
An easy way to find the real density (or a good approximation thereof) would be to jam a coffee can or other metal tube into the snow, capturing a sample w/ as little deformation as possible. Measure the depth of the snow (should be the same as the height of the can). Melt the snow in the can, measure the depth of water. This number is your snow water equivalent. Divide the melted depth (SWE) by the raw depth to get the density. That would give you a better number than just using the .33 average...
Obviously, a true snow survey sample uses a tube that captures a complete vertical sample and the sample is weighed in the field (unmelted), but a set of real survey tubes and scales can be a bit spendy...
john
.