They kill crops, coax snowfall to fall out of the atmosphere, and help ski resorts stay open during unseasonably warm weather. These tiny life-forms are called ice-minus bacteria, and their talent is forcing water vapor to form ice—creating frost at temperatures where the water wouldn’t otherwise freeze. Today scientists may finally understand how these bacteria work their molecular magic.
A team of scientists led by Tobias Weidner, a physicist at the Max Planck Institute for Polymer Research in Mainz, Germany, has just completed a fascinating new study on how ice-minus bacteria manipulate water into freezing. Weidner’s team tracked how they use two strange tricks to stack water into ice crystals, molecule by molecule.
Whether on the ground or airborne, ice-minus bacteria can have an enormous effect on making sure water becomes ice as close to the freezing point (0 degrees Celsius, or 32 Fahrenheit) as possible. “For example, if you have pure water suspended in the atmosphere, sometimes the water droplets won’t freeze until they’re at -40 degrees centigrade. But if these bacteria are around, that freezing point can drop to just -5 degrees,” Weidner says.
Ski resorts put these bacteria in with the water and pressured air they blast from snow cannons to make fake powder.
Behind the Scenes – How Snowmaking at Ski Resorts Works
Snow Making at Heavenly Ski Resort
Mother Nature has been especially cruel this drought year to the ski resorts in Lake Tahoe. Snowpack is 25 percent of the historical average and January 2015 was the driest on record. But Barrett Burghard, who has been making snow at Heavenly for 27 years, isn’t too concerned about California’s ongoing drought. His team of snow makers and groomers have been working around the clock, and as of early March, they’ve succeeded in opening nearly half of the resorts 4,800 acres for skiing.