How much does snow actually weaken the ice?

[DRock]

We have about 4"-5" of black ice around here and with this big storm coming through soon we are expected to get at least 20" of snow. I know that the snow insulates the ice so it will grow at a much slower rate but with this insane amount of snow coming down on such thin ice can we expect it to still be safe with all the additional weight?

Some quick calculations show that 24" of snow adds around 17lbs onto your actual "footprint" but what concerns me is the entire area around you has snow on it so in reality there is an added 600lbs of weight in a 5'x5' square area of where you stand. Now I have no idea what a snowmobile has for a footprint on the snow but I know that there needs to be substantially thicker ice to get me out there on any sort of machine and 4" will not cut it.

What do you guys think?

[Kevin23]

Wouldnt catch me out on it in water over 3 feet. Personally, I'd wait for 6"+ or until it rains and melts all that snow.

[Skipper]

20 inches of snow should sink and flood 5'' of ice pretty dang bad. If it doesn't, it will be a slushy mess at least.

[DRock]

I just did a few more calcs and they recommend 5" of ice for a 462lb sled and 2' of snow will be around 948lbs for an equivalent area of snow. 

That means we would need 10" of solid ice to support the weight of the snow we are about to get!

Damn that is not good news at all...

[Ole Polanski]

   20 + inches of snow is bad enough but boy do I ever hate water on the ice under the snow!!!   Thank God ice still floats!!!  Where did I put them snowshoes???

[Whopper Stopper]

Keep in mind ice thickness varies from spot to spot and not all ice is the same quality. I certainly would allow a little leeway, a calculator may get you a wet a_ _.

                        WS