An omen of snow? Yukimushi.
The other day at work, a colleague casually told me, “We’ll be getting snow in the next two or three weeks.” Naturally, I asked if he’d heard this on the news. To my surprise, he shook his head and replied that the Yukimushi have started to emerge. He was a former ALT from the beautiful prefecture of Hokkaido, now living in Fukushima; today’s blog will focus on a piece of folklore that actually originated in Hokkaido.
Curious, I pressed further. I’d just seen a report that northern Japan was experiencing unseasonably warm weather, so the prediction of snow caught me off guard. But according to my colleague, the answer was all around us: the sudden appearance of yukimushi, delicate “snow bugs” drifting through the air outside our workplace. Local folklore from Hokkaido and northern Tohoku, and a hint of pseudoscience, claim that when these ghostly insects emerge, snow is sure to follow within a month.
Intrigued by this natural omen, I set out to discover the truth about the mysterious white creatures behind this wintry legend. Today’s blog dives into the world of the yukimushi.
Known to scientists as Prociphilus and in Japanese as Todononeoowatamushi, these unusual aphids look as if they’re dressed for winter themselves, covered in white, waxy hairs that give them a soft, woolly appearance. They gather in clusters, and when caught on a gentle breeze, they drift through the air like tiny living snowflakes.
In Japanese folklore, these delicate insects are celebrated as the true heralds of winter. The story goes that once you see yukimushi floating by, the first snowfall is just around the corner, typically within 7 to 14 days. These harbingers tend to emerge on calm, mild afternoons between early October and mid-November, adding an air of quiet anticipation to the changing season. As I write, it has been about a week since Hokkaido received its first snow, where I live, and work is snowless.
So let’s investigate the science behind these dancing snowflakes. The emergence of Prociphilus can be explained by seasonal migration, which is triggered by a drop in temperatures. This migration isn’t like that of birds that fly to a different hemisphere to escape the harsh winter. This migration is more localised and on a much smaller scale. Prociphilus, usually called Todomatsu (Sakhalin fir), is home; they usually spend most of the warmer months feeding on the foliage, and when temperatures start to drop, they migrate upwards. They drift upwards to the branches of the achidamo (Manchurian ash); here they lay their eggs in hopes they will hatch before the first frost kills them.
The thought of my first true Japanese winter fills me with a mix of excitement and nerves, especially as the first snowflakes begin to swirl through the air. Cold weather has never been my strong suit, and the winters here are nothing short of fierce. Snow stacks itself against the windows, and climbing the mountain turns into a real adventure. My fascination with local folklore led me to the story of the Yukimushi, the so-called snow bugs. I cannot wait to see if their appearance really does predict the coming snow. If the legend holds, I will share an update on the blog in two weeks. For now, it seems that in the chilly northern prefectures, spotting these tiny white insects is a sure sign that winter is on its way.
