That winter, sextillions of snowflakes fell from the sky. That’s billions of trillions of them that have now mostly melted away as spring approaches.

Few people looked at each other closely.

Kenneth G. Libbrecht, professor of physics at the California Institute of Technology, spent a quarter of a century trying to understand how such a simple substance – water – can freeze in a myriad of forms.

“How do snowflakes form?” Dr. Libbrecht said during an online conversation on February 23 hosted by the Bruce Museum in Greenwich, Connecticut, “And how do these structures appear – and as I would like to say, literally out of nowhere?”

One of the people led by Dr. Libbrecht’s snowflake research and photography were fascinated by Nathan P. Myhrvold, a former chief technology officer at Microsoft who has since pursued projects in a myriad of scientific disciplines such as paleontology, cooking, and astronomy.

Dr. Myhrvold, an avid photographer, met Dr. Libbrecht first saw it more than a decade ago and in the spring of 2018 he decided to photograph the intricate frozen crystals himself. He remembered thinking, “Oh, we’ll just throw something together and be ready for winter.”

But as with many of his projects, things weren’t as simple as Dr. Myhrvold had planned it.

“It turned out to be massively more complicated than I thought,” said Dr. Myhrvold. “So it took 18 months to build the damn thing.”

The “damn thing” was the camera system for taking pictures of snowflakes. He wanted to use the best digital sensors that could capture a million pixels. “The real snowflake is very, very fragile,” he said. “It’s super complicated. So you want a high resolution. “

However, this type of sensor is much larger in area than the images normally produced by microscope lenses. This is the result of choices made by microscope manufacturers nearly a century ago.

That meant he had to find a way to stretch the microscope image to fill the sensor.

In his tinkering, “I came up with a custom optical path that it actually works with,” he said.

Then there is the housing for the optics. This is usually made of metal, but metal expands when it is warm and shrinks when it is cold. If he took the machine from the warm interior to a cold balcony where he was collecting the snowflakes, “it would mess up the whole microscope,” said Dr. Myhrvold and made it impossible to keep everything in focus.

Instead of metal, he used carbon fiber, which doesn’t expand or shrink noticeably.

Dr. Myhrvold also found a special LED manufactured by a company in Japan for industrial purposes that would emit bursts of light of 1/1000 for as long as a typical camera flash. This minimizes the heat given off by lightning, which could melt the snowflake somewhat.

To look at something under a microscope, a sample is usually placed on a slide. But glass stores heat. That also melts the snowflakes. So he switched from glass to sapphire, a material that cools down more easily.

He was ready by February 2020. But where can I find the most beautiful snowflakes to photograph? At first he thought he could just go to a ski resort – maybe Aspen or Vail in Colorado or Whistler in British Columbia.

But these places weren’t cold enough.

“Powder that a skier likes to ski through is actually quite a bit of powder,” said Dr. Myhrvold. “There’s not much beauty in these things.”

In fact, the snowflakes that meet most people most of the time are rarely what people consider snowflake-shaped.

Water is a simple molecule made up of two hydrogen atoms and one oxygen. When temperatures drop below 32 degrees Fahrenheit, the molecules begin to stick together – that is, they freeze.

A snowflake is created in a cloud when a drop of water freezes into a tiny ice crystal. The shape of the water molecules causes them to stack in a hexagonal pattern. That is why the archetypal snowflake has six arms.

Then the crystal grows and absorbs water vapor from the air. Vaporize other droplets nearby to replenish the vapor. “It takes maybe 100,000 drops of water to evaporate to make a snow crystal,” said Dr. Libbrecht.

How the crystal grows, however, depends on the temperature and humidity. In the 1930s, the Japanese physicist Ukichiro Nakaya was the first to grow artificial snowflakes in his laboratory. By varying the conditions, he was able to catalog which types form under most conditions.

Generally, when temperatures are just below freezing, the snowflakes are simple hexagon plates. At around 20 degrees Fahrenheit, hexagonal pillars are the predominant shape. It is between 15 degrees and -5 degrees Fahrenheit that the archetypically beautiful snowflakes usually form.

At these temperatures, the tips of the hexagon grow into branches. The branches then produce other branches and smaller hexagonal plates. Slight fluctuations in temperature and humidity affect the growth pattern, and conditions are constantly changing as the snowflake falls to the ground.

“Because it has this complicated path through the clouds, there is a complicated shape,” said Dr. Libbrecht. “They all follow different paths, so each one looks a little different depending on the path.”

To find the beautiful snowflakes, Dr. Myhrvold to the north, much further north. He and a few assistants hauled about a thousand pounds of equipment to Fairbanks, Alaska; Yellowknife, the largest parish in the Canadian Northwest Territories; and Timmins, Ontario, about 150 miles north of Lake Huron.

A month later, the coronavirus pandemic put the company on hiatus. Dr. However, Myhrvold was able to capture what he called the highest resolution images of snowflakes of all time.

That claim has angered others in the snowflake world, including Don Komarechka, a Canadian photographer who takes a decidedly lower technical approach. He uses a store-bought digital camera with a high-performance macro lens. He doesn’t even use a tripod – he just holds the camera while the snowflakes sit on a black mitt his grandmother gave him.

“Incredibly simple,” said Komarechka. “It’s so accessible to anyone with any camera.”

He said about Dr. Myhrvold’s bespoke system: “I think it’s a little overhauled.”

Mr. Komarechka also takes a different approach to lighting, using the light reflected from a snowflake, while Dr. Myhrvold catch the light passing through. “You see texture and sometimes beautiful rainbow colors in the middle of a snowflake,” said Komarechka.

The rainbow effect is the same as a soap film, but the colors “often appear much more solidly than with a soap film or something else,” he said. “It’s almost psychedelic colors that look almost like a tie-dye t-shirt.”

To Dr. To counter Myhrvold’s claims, Mr. Komarechka took a picture which he says was of even higher resolution. Dr. Myhrvold responded with a long counter-argument, explaining why his pictures were nonetheless more detailed.

In practice, Dr. Myhrvold’s images are sharper when printed in large sizes on paper. They can be purchased in sizes up to 2 x 1.5 meters.

“In that very narrow sense, yes, that’s what Nathan says, and he’s not wrong,” said Dr. Komarechka.