According to experts, the winter season’s companions and symbols of the holiday season come in a stunning variety of shapes and sizes. Each one is unique. So, what is the largest snowflake ever recorded? What do snowflakes look like? And what determines their various forms? Here’s a real-life case that seems almost fantastical.
In 1887, Matt Coleman, a ranch owner in western Montana, noticed enormous snowflakes falling onto one of his pastures during a snowstorm. He reported that they were “as big as milk pans.” According to the Guinness World Records, these colossal snowflakes measured 38 centimeters wide and 20 centimeters thick, still holding the record for the largest snowflakes ever documented. To this day, despite the lack of photographic evidence, these specimens remain popular examples for studying precipitation. However, readers might still wonder: is it really possible for a single snowflake to be the size of a dinner plate?
Commenting on this phenomenon, Kenneth Libbrecht, a physics professor at the California Institute of Technology and a leading expert on snowflakes, has dedicated much of his career to studying and photographing them. He has authored several books on the subject and created a website devoted to it. The snowflake specialist asserts that such gigantic snowflakes are “rare but not impossible.” He explains that there is a common misconception about what makes a snowflake a true snowflake. When people refer to a snowflake, they are actually talking about an ice crystal, where water molecules arrange themselves in a hexagonal pattern. This characteristic hexagonal shape is familiar to all of us, as noted by Professor Libbrecht in an interview with Live Science.
Upon closer examination, it becomes clear that a single snowflake can be a standalone crystal or consist of hundreds or even thousands of crystals. They break apart and clump together in the air, forming clusters or aggregates. “In cold places, you often encounter these large aggregates falling from the sky,” Professor Libbrecht continued, “people call them snowflakes, but I prefer to call them aggregates.” According to the expert, it’s entirely possible that Coleman’s famous giants were simply a mass of ice crystals that collided and formed one combined snowflake.
As for the largest crystals he has ever seen, Kenneth Libbrecht describes them as true monsters, though not quite as large as those reported by the Montana rancher. Libbrecht’s giants typically measure around 10 millimeters wide, roughly the size of a dime. His laboratory is designed to create ideal conditions for snowflake formation: there’s no wind to break them apart in the air, and the optimal temperature reaches minus 15 degrees Celsius. This is why laboratory snowflakes can grow to such impressive sizes. In the wild, such large crystals are rare due to weather conditions. Usually, snowflakes break apart due to wind before they can grow large.
Regarding the variety of shapes, while these crystals may be small in size, the diversity of forms they can take is astonishing. In the 1930s, Ukichiro Nakaya, a Japanese physicist who created the world’s first artificial snowflakes, documented numerous different shapes on a morphological diagram. Depending on the temperature and humidity during crystal formation, their appearance varied from simple prisms and columns to delicate rosettes and star shapes with fern-like branches. Some form at slightly below freezing, while others require temperatures of minus 25 degrees Celsius. Growing snowflakes in the lab is highly educational, as it is the only way to truly understand what happens to these unique crystals in nature.