How far can a WiFi signal reach in snow?
firstly, I want to advice not to rely on whatever you are gonna craft, when it comes to your personal risk assessment when going off-slope skiing or snowboarding. There are avalanche rescue systems out there that engineered and tested to safe lives.
Now, for your question regarding the propagation of a wifi signal in snow (not in snowy air, as some have interpreted it), IT DEPENDS (as always)...
And mostly it depends on the consistency of the snow (conductivity, density, water content) and on the depth of the snow layer above soil (as the soil partly reflects signals).
Signals with lower frequency propagate better in snow, as they do in/through most materials.
I want to point you to a IEEE paper that could give you a better understanding on what to think about in your hobby project and where the research is standing.
As I can not publish their research here, I think I can safely quote them and recommend reading the paper:
&quot;As can be seen, WiFi frequency (2.45 GHz) presents an excessive attenuation with the distance, besides its greater susceptibility to the snow conditions. On that basis, lower frequencies will be better for through-the-snow communications systems.&quot;
They modeled and tested 0.4, 0.8 and 2.5 GHz signals, and compare it to the cited frequencies.
Note, they assume a 2m depth as their standard case for engineering, as they assume a burial below 2m has very low likelihood of survival (due to trauma, weight of snow, etc.). Other research, they cited in the paper, used a 1 m burial of the beacon and a 3 m snow layer over soil.
This does not answer your question directly, but I hope it helps developing a better understanding. Also, if you can, go test it (without getting burried) ;-)