Why does water melt snow?
And I don’t mean warm water, I mean water at what must presumably be around freezing point.
To explain what I mean, consider the following scenario. There is a sudden snowstorm, lasting about half an hour. If the ground was previously wet (e.g. it had been raining earlier), the snow will melt. If not, the snow will lie on the ground until it gradually melts if the temperature is above zero.
Why does this happen?
I can come up with all sorts of plausible explanations, without ever referencing Water-9 (see Ice-9):
- liquid water conducts heat better than paths, grass or soil, so if it’s even slightly above freezing it will melt faster
- water on the ground has dissolved minerals (or whatever) in it that depress the melting point, meaning when snow lands on it it will start to melt
- Because snow is mostly air, it acts as its own insulating material if placed on a poor heat conducting surface. However, water would percolate through the snow crystal removing the insulation and turning it into a good conductor of heat
Now the key point here is plausible. They all — to me at least — sound like entirely reasonable possiiblities to explain why snow melts more quickly on wet than dry ground.
Of course the only scientific sounding explanation I’ve found online is that this is caused by “wet snow” which is half-melted anyway before it hits the ground. But I’m not entirely convinced as that sounds like a cop-out. So please experiment…
Next time it’s snowing near you, and the ground is dry, pour very cold water over a small area on the ground (works best on non-porous surfaces so it doesn’t drain away).
Then get back to me and let me know whether the snow settles equally on the wet and dry surfaces (as we would expect if it is just the type of snow) — or whether there is a difference between the wet and dry areas…
Hello. I am 
whatever temperature water is, if it’s still water it’s obviously warmer than the snow.
and as the water is already on the ground there’s a much larger amount of the warmer water, hence the overall temperature of the snow will rise and it will melt.
or if rain falls on the snow then that means the overall temperature is rising (as it’s raining, not snowing), so the snow will melt anyway and the impact of the rainwater just helps it along.
i reckon
Wet ground is probably able to absorb more energy than dry ground because water is good at absorbing heat. So if the ice would melt anyway it will melt faster.
However water is extremely funny stuff, have a look at this site:
http://www.lsbu.ac.uk/water/anmlies.html