How snow making works
By Marshall Brain
http://www.JewishWorldReview.com | (MCT) Let's imagine that you are standing at the top of a phenomenal black diamond ski run. As you look down the hill, a mile-long runway of beautiful, clean, fluffy snow stretches like a white carpet toward the ski lodge at the bottom.
But when you look to either side of the trail, there may be no snow at all. Even in the "heart of winter," nature can be fickle. Malibu may be seeing snow flurries for the first time in 20 years, but some ski slopes haven't had a flake.
In other words, the ribbon of snow you see at the ski slope may be completely artificial. The whole thing is created at night using snow guns, specialized snow bulldozers and a big lake of water in the valley.
There's even some dead bacteria thrown in to help the process. The technology that makes this all possible is absolutely fascinating.
The first thing you need is the right weather. It's got to be cold to make snow, and we still depend on nature for freezing temperatures.
Fortunately, despite the worries about global warming, it usually gets cold enough in the mountains to make snow at night. Temperatures in the teens are perfect. But if the humidity is low enough, you can make snow at 30 degrees Fahrenheit.
Next you need a lake full of H2O. Covering a ski slope takes a gigantic amount of water. If you think about it for a minute, you can see why. To blanket one acre of slope in 1 inch of snow, you need about 12,000 gallons of water. A good size ski run may measure 30 acres or more from top to bottom. And a ski run needs at least a foot of snow to be credible for skiing. So, just for a single run, you have to pump more than 4 million gallons of water up the hill - enough to fill 300 backyard swimming pools. A big ski resort can burn through 10,000 gallons of water every minute when it is making snow.
Lots of ski resorts add something called a nucleator to the water. When water forms into ice, a nucleator speeds up the process by giving each ice crystal a seed to start on. Using a nucleator, you can make snow in warmer temperatures. One popular brand of nucleator is called Snomax, which is made from dead bacteria cells. They grow the bacteria in giant vats, freeze-dry their little bodies and then zap them with nuclear radiation to make sure they are sterile before shipping them off to ski slopes.
I know what you are thinking: "Bacteria to make snow?" Turns out that some species of bacteria (Pseudomonas syringae is one of them) have special ice-nucleation proteins on their outer cell walls.
All of that nucleated water feeds into the snow guns. The simplest gun is nothing more than a lawn sprinkler and a huge fan. The sprinkler atomizes the water, and the fan blows enough cold air through the droplets to freeze them. More sophisticated guns use giant air compressors and then shoot the compressed air through the water to atomize and freeze it.
Now that you've made all this snow, you have to put it in the right places. That's where the snow groomers come in. A groomer is really just a specialized snow bulldozer that can push artificial snow around. They have very wide metal tracks so they can move up and down the mountain easily, even when things get icy. For the really steep black diamond trails, a winch can help pull the groomer up the hill.
As you might imagine, all of this pumping and blowing uses a lot of electricity. Some resorts burn through so much juice that they actually build their own power plants. The HoliMont ski resort near Buffalo, N.Y., has a plant that produces 3.5 megawatts. And this gets us to an important point about making artificial snow. The snow that nature brings is absolutely free. To make snow artificially you need to pay for electricity, nucleators, equipment, maintenance and people. Those costs can really add up.
All of which means that, whenever the real white stuff falls from the sky for free, it makes the owners of ski resorts very, very happy. As long as there is not too much of it.
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