Bacteria (Pseudomonas syringae) found in the Amazon rainforest may help form ice by manuplating the forces between water molecules, new research suggests. It all has to do with the ice nucleation process that forms ice crystals in the atmosphere and, thus, snow. You probably know that raindrops and snowflakes form around something. There's always a central nucleus that serves as the backbone of the water molecule structure. P. syringae gets this skill from the proteins that cover its surface membrane. The proteins basically form a physical structure that water molecules latch onto. That structure also orients the molecules in a way that prompts the formation of ice crystals. It's these proteins that really serve as the instigator of ice nucleation and they're incredibly efficient at it, far more so than dust. That means that P. syringae can get water to freeze at higher temperatures than would happen without its help. Pure water won't crystallize until temperatures dip down to -40 degrees F. If the water in our atmosphere were pure, most of us would never see snow. Add in the proteins from P. syringae, though, and, suddenly, ice can form at 27 degrees F. You can even get ice formation at higher temperatures than that, depending on the specific strain of P. syringae involved, and how densely the ice-forming proteins are packed along its surface.
Commercial snow machines use the proteins (though not the bacteria itself) to help instigate the creation of snow on ski mountains. In other words, you can thank P. syringae for all the snowboarding and downhill ski action the Winter Olympics.