This winter, an Arizona ski resort, Snowbowl, will be the first to use treated sewage water, and sewage water alone, to make manmade snow. Recycling’s usually a good thing, but opponents of the plan worry about chemicals left in the snow, and an August report by a civil and environmental engineer says that the recycled water, already used for irrigation in Flagstaff green spaces, may contain antibiotic-resistant bacteria.
When winter doesn’t hold up its end of the snow bargain (we’re looking at you, this winter), ski areas often make their own, using devices like the one above and plenty of water. A short piece on the New York Times site describes the moment in 1950 when modern snowmaking was invented, when Wayne Pierce, an employee at Mohawk Mountain in Connecticut, improved upon the owner’s plan of trucking in tons of shredded ice:
He figured that a drop of water, propelled through below-freezing air, would turn into a snowflake, [colleague Arthur] Hunt recalled. Along with Dave Richey, their partner in a ski factory, they slapped together a spray-gun nozzle, a 10-horsepower compressor and a garden hose into something of a D.I.Y. snow gun. They experimented with it all night. “By morning,” Hunt wrote, “we had a 20-inch pile of snow over a diameter of 20 feet.” The contraption was later used at Mohawk Mountain.
Snowmaking has since developed quite a bit. While early attempts at snowmaking used just water, these days a special mixture of dirt and water is used to get natural freezing: as we’ve written before, ice crystals usually need a particle to coalesce around, which can be a bit of dirt or even bacteria floating in the atmosphere. These particles are called nucleators.
What’s the News: Bacteria are everywhere—in us, on us, around us. But they’re also floating around in the atmosphere, and researchers cracking open hailstones have now discovered them at the core, lending credence to the theory that bacteria jump-start the atmospheric process of forming snow, hail, and rain as a way to hitch a ride down to Earth.
Scientists have suggested for years now that the effects of a warming planet won’t show up in a uniform fashion across the globe—different locations won’t see glaciers retreat or sea levels rise at the same rate. Some places are particularly confusing because they show signs that seem backward to one’s expectations for a hotter Earth. One of the those confusing outliers for climatologists has been the sea ice off Antarctica.
While the amount of sea ice in the Arctic has been trending downward, Antarctic sea ice has actually expanded even as the area has warmed (and as ice shelves collapsed on the continent). This week, in the Proceedings of the National Academy of Sciences, Jiping Liu and Judith Curry put forth an explanation for this paradox. But, they say, the ice growth probably won’t continue.
How do you punch a hole in a cloud? Fly through it.
Meteorologists had long figured that aircraft were part of the explanation for crazy-looking “hole-punch clouds” like this one. When propeller planes fly through a cloud, they thought, it can exert air pressure that cools water extremely quickly to produce ice. If water vapor condenses on that ice, snow falls from the sky and leaves a conspicuous cloud hole.
Now, thanks to a happy accident, researchers confirmed that planes can cause these cloud holes, and that even jets, not just prop planes, can do it.
Andrew Heymsfield, a scientist with the National Center for Atmospheric Research, was aboard a research plane near the Denver airport in 2007 when he unwittingly flew through a flurry of snow produced by a hole-punch cloud.
The plane was loaded with instruments for studying how ice forms in clouds. Radar from the ground picked up a strange echo in their wake, indicating oddly-shaped snowflakes. “We didn’t know it, but we went right through this precipitation feature that was spotted from the ground,” Heymsfield said [Wired.com].
Their readings, when matched up with the path of planes in the area, helped unravel the mystery:
The researchers then linked satellite images of hole-punch clouds to flight schedules to show that jet aircraft, not just propeller planes, can also punch holes and produce snow. The supercooled droplets freeze after passing over the jet planes’ wings, Heymsfield said [Wired.com].
Their work will soon be published in the Bulletin of the American Meteorological Society.
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Image: Alan Sealls, chief meteorologist, WKRG-TV
When the Copenhagen climate summit ended in disappointment and finger-pointing, we saw again just how difficult it would be to get the world’s nations on board for an agreement to lower greenhouse emissions and slow global warming. This week brings another reminder of how far away we are from meaningful action: We can’t even get past the difference between weather and climate.
It’s bitter cold this week, even for January. Beijing had its coldest morning in almost 40 years and its biggest snowfall since 1951. Britain is suffering through its longest cold snap since 1981 [AP]. The southern United States is in the grip of freezing weather; the Midwest has seen dangerously cold wind chills far below zero. Trying to stave off the inevitable “where’s your global warming now” chants, the AP and other news sources rushed to run pieces trying to get across—one more time—that weather isn’t climate. The chants came, inevitably. But despite pundits and columnists who try to conflate the two to take the same old swings at global warming, a single bout of cold weather—or hot, for that matter—doesn’t actually say diddly squat about long-term climate patterns.