A study of hailstones has found large numbers of bacteria at their cores. It turns out that the bacteria help create the snow and hail, since their coating of protein causes water to freeze at relatively warm temperatures. In fact, bacteria works so well that it's used in snow-making machines.
Bacteria may be involved in this cycle as a way of spreading THEMSELVES in a wider area, which isn't a problem for us unless they are the type of bacteria that can cause disease. Researchers are worried that the glaciers that are melting all over the world may release bacteria that hasn't been seen on earth for thousands of years--germs that our immune systems are no longer able to fight off.
In 1998, Whitley Strieber had never heard of climate change, but the Master of the Key burst into his hotel room in Toronto and warned him that glaciers would soon melt, resulting in sea level rise (The new, UNCENSORED edition of The Key--Subscribers can still listen to this show--with a foreword that talks about how many of his statements later turned out to be true, is in bookstores NOW).
In BBC News, Jason Palmer quotes microbiologist Brent Christner as saying, "(Bacteria in snow is) an interesting idea that's been thrown around for decades but only recently has the data accumulated to support it."