Wikipedia tells us that the surface area of Prince Edward Island is 5,660 km2.
The square root of 5,660 is 75.23, meaning that, if reconfigured to be a square, PEI would be 75.23 km by 75.23 km.
NASA tells us that “freshly-fallen snow has a density of 50 kg/m3.”
One centimeter of freshly-fallen snow on a 75.23 km by 75.23 km box is a cube that’s 7,523,000 cm by 7,523,000 cm by 1 cm.
That’s a cube that’s 56,595,529,000,000 cm3 or 56,595,529 m3.
At 50 kg/m3 that means that a one centimeter snowfall on Prince Edward Island has a mass of 2,829,776,450 kg, which is 2,829,776.45 metric tons.
So an 86 cm fall of snow has a mass of 226,382,116 metric tons.
Dump trucks vary, but it seems their capacity is around 32 metric tons, so that’s about 7 million dump trucks worth of snow.
Is my math correct?
Looks good. You could probably take this a step further and calculate the amount of PEI (or even Charlottetown) that's road (I'm sure TPW publishes that) and thus better understand how many truck trips it would take to clear the roads, and how long that could be expected to take.
It's likely well undershot too, as when snow accumulates it typically insulates the heat from the earth and forms water and ice (at least partially.) They estimate compacted snow to be about 200kg/m3, and ice and water would certainly be higher than that.
I am not sure if the Weather Canada measures account for this (i.e, some kind of measure and dump technique where snow's not allowed to compact) but in any event, it is a bloody lot of mass in such a short period of time.
I'm not sure about anyone else, but my first thought was "With an extra 226 million tonnes of weight, how faster is PEI sinking into the Atlantic?"
I can't be the only one who is thinking that, can I?
I don't know the geology of PEI, but I suppose it's a lot more than 86cm down to the sea floor, and the column that's supporting it isn't made of packing peanuts. So that 226 million tonnes is a 226 million tonne drop in the bucket, I figure.