FLORA LICHTMAN: Sure there's sledding, snowmen, skiing, but a winter storm can also mean safari.

KEN LIBBRECHT: You really just need a snowy day. Take a magnifying glass, go out, there's all sorts of different things you can see.

FLORA LICHTMAN: That's Ken Libbrecht, the physicist at Caltech who also happens to be a snowflake expert. He's been hunting flakes for years and documenting them before they melt with this microscope camera rig.

KEN LIBBRECHT: My travel with that the hard part is getting it through airport security.

FLORA LICHTMAN: Snow crystals come in roughly 35 flavors Libbrecht says. Some more common than others of course.

KEN LIBBRECHT: Stellar dendrites are pretty common standard sort of shopping mall snowflake with six branches.

FLORA LICHTMAN: Then there's the variant fern-like stellar dendrites.

KEN LIBBRECHT: ...and they look like a little bitty ferns.

FLORA LICHTMAN: Also common are...

KEN LIBBRECHT: ..needles, columns. One of my favorites are capped columns.

FLORA LICHTMAN: Which look kind of like a satellite or...

KEN LIBBRECHT:...two wheels on axle. Unfortunately the most common thing you'll find is just kind of junky looking snow looks like sand.

FLORA LICHTMAN: The least common, the ivory-billed woodpecker of snowflakes is big...

KEN LIBBRECHT: ...five millimeters in diameter and nicely symmetrical with lots of intricate markings. Those are really gorgeous and hard to find.

FLORA LICHTMAN: But you can increase your chances if you seek out snowflake hotspots.

KEN LIBBRECHT: Northern Ontario is a good spot. Vermont and Michigan and I have been there. Northern Japan actually is pretty good. I'm anxious to try to Siberia.

FLORA LICHTMAN: See certain conditions breed better crystals.

KEN LIBBRECHT: The best temperature is around five degrees Fahrenheit. Sometimes though you can see it's really nice crystals just below freezing.

FLORA LICHTMAN: Ok a little review of where snowflakes come from. They're born in the clouds. It all starts with a speck of dust or bacterium.

KEN LIBBRECHT: Gunk in the air.

FLORA LICHTMAN:...and the gunk floats around the cloud.

KEN LIBBRECHT:...for half a mile.

FLORA LICHTMAN: Picking up water molecules.

KEN LIBBRECHT: Then they shuffle around a little bit until they find the right spot to sit in and that the water molecules themselves are lined up in the hexagonal array. That's where the the order is generated.

FLORA LICHTMAN: ...and that order is what makes it a crystal.

KEN LIBBRECHT:...and as a grows larger the points of the hexagon stick out a little bit in the air so each of the six corners sprouts and arm and that's one of the things we're trying to understand in details how crystals grow.

FLORA LICHTMAN: The details of that growth are determined by the microenvironment, the flake encounters, as it travels through the cloud.

KEN LIBBRECHT: Humidity is low the crystals grow slow and humidity is high they go fast.

FLORA LICHTMAN: In other words of flakes identity is shaped by the environment it grows up in and because two snow crystals aren't likely to follow the exact same path, you're not likely to find two of the exact same flake. Just how environment affects crystal growth is something Librecht studies in the lab, by growing his own snowflakes.

KEN LIBBRECHT: We call these designer snowflakes. You can sort of dial-up what you want.

FLORA LICHTMAN: Give it the right environment and something to grow on and it'll build itself.

KEN LIBBRECHT: A really nice example of how really complicated structures emerged spontaneously not alive test the DNA or anything like that genetic code. It just happens. To understand more about how works will be able to use it for something or at the very least we'll just understand how it works.

FLORA LICHTMAN: Happy new year. For Science Friday, I'm Flora Lichtman.