It may not just be one heavy snowfall that causes a problem but perhaps a collection of snowstorms.
How much snow on a roof is too much.
But as the chart below shows packed snow with ice can easily overload a roof once it reaches about 12 off depth.
How much snow can my roof hold.
These questions aren t quite so easy to answer because there are several variables.
The drifts on the roof were 5 feet deep.
Driving winds can change the depth of the snow and snow depth on the ground does not necessarily equate to the snow depth on a roof.
Trying to work out whether the snow load is too much for your particular roof requires quite complicated maths.
Remove excess snow and ice.
That means clearing amounts above 20 pounds per square foot.
A snow rake with a long extension arm is recommended.
How much snow a roof can hold depends on the type of snow roofline and material among other considerations.
Last winter we had snow on the ground that was up to our hips.