Right next to my little city there are large dumping grounds for snow cleared from the city streets. In fact, it is just across a major road. Some people could walk out of their yard, across the street and into the snowy mountains.
The piles get to be 2-3 stories tall, and parking lot sized. In late spring the city uses machinery to spread it out, probably because it wouldnt fully melt otherwise. The snow dump is on slightly lower ground and features drainage ditches and pipes into a local creek.
To those unfamiliar with the practice of snow removal, there is a lot of grit, gravel, detritus and dust mixed in with snow. You dont normally see it, but as it melts the snow becomes dirty looking on its surfaces. This can cause an insulation effect.
Further, a large pile of snow and ice has a smaller surface area than snow spread out; it is self insulating. It is also compressed; the city can drive their dump trucks on top.
So I had a sudden thought(if thoughts from years ago could be called sudden), that if they left the snow alone, within a few years, our local weather and biome could be drastically skewed. They could build a small glacier.
Not that they particularly need to, but its an interesting type of environmental modification that nobody seems to try.
Eventually it seems it would become self perpetuating. Maybe.
Actually the dirt and grit decrease reflection of light and increase heat absorption. Also, those snow piles aren’t densely packed. They shrink considerably if compressed down to hard ice.
However, there have been experiments where large, deep holes are filled with plowed snow, and then covered with insulated blankets over the summer. The idea is to use the ice as a heat sink for large air conditioning systems. Don’t know how that’s worked out so far.
They are definitely packed hard enough to support the weight of the trucks and other machinery. They build ramps, drive up top and dump their loads there. They dont need to be pressed to solid ice for that.
Gravel will form a crust on a snow pile. Exposed areas melt faster; the caped areas are shaded. Here is a poor example, but you can see what I mean: http://2.bp.blogspot.com/-SIT8_J16u7A/Tbn-e8m3IKI/AAAAAAAAEf4/CwYINdA4-JI/s1600/Snow%2Bpile%2BApr%2B28.JPG
The graveled areas form little ridges. While rock does absorb heat, it also doesnt transfer it further in very efficiently. the pebbles sit lightly on others, barely touching.
In the days before air conditioning, ice was harvested from lakes and ponds, cut and packed in sawdust (excellent insulator). The ice was stored in warehouses (icehouses)-it would frequently last into the next winter.
There are many such places. Polar Caves in New Hampshire gets its name from being such a place. The locals used to use it as a natural refrigeratoe.
Even though it’s exposed, and not a cave, the bottom of the gorge at Letchworth State Park in upstate New York frequently has ice year-round, because it’s so deep and parts get virtually no sun. As with the snow piles cited above, the ice mounds at the bottom of Letchworthy are often coated with rock dust and crumblings.
In the spring, more ice and snow is removed by direct sunlight, than by thawing temperatures. In direct sunlight, ice and snow will “sublime”, that is, transform directly from solid to gaseous without passing through a liquid stage. (A few other solids also do this, including Iodine crystals.)
So all that is needed to retard the disappearance of winter snow and ice is to cover it, so that it does not receive direct solar radiation. The impurities in the snowpile, to some extent, form an opaque covering over the snow, as others have described above.
In the northern states, before there was electrical refrigeration, ice was saved from the winter in covered and sheltered warehouses, and delivered daily all summer to people’s houses, to keep things cool in their “ice box”, which my mother continued to call her modern refrigerator until she died in 2007. I believe northern lake ice was shipped by train or river barge to southern states for refrigeration.
Not exactly related to the OP but an interesting bit of trivia - when ice was first created using refrigeration equipment, it was referred to as “synthetic ice”.
I can’t find a cite. Google returns nothing but references to a commercial polymer used for skating. But I saw it in a Scientific American in a monthly feature they have called “50, 100 and 150 years ago”.
Maybe. They reprinted an actual article from the time and I recall that article saying “synthetic”, but I could be remembering wrong, or maybe both terms were used.
