In Japan's popular mythology, especially in mountainous and cold regions, there is a quite terrifying type of youkai (spirit/monster): the Snow Hags, known as Yukinba (雪婆, “snow hag/granny”) and Yukifuriba (雪降り婆, “falling snow hag”).

Who are these hags?

Both are variations of entities linked to winter and blizzards, but with different appearances and "horror styles":

• Yukinba is described as a grotesque monster: an aged female figure with a deformed body, often depicted walking or hopping on a single massive leg. For whatever reason, this one-legged detail appears in several of these cold-related figures, such as a group of monsters called Ippon-datara.
• Yukifuriba has a more “poetic” name (the old woman of the falling snow) and, contrary to the monstrous appearance of the Yukinba, looks like a normal elderly woman with white skin and simple clothes — almost a “cadaverous” version of the famous Yuki-onna (the Snow Woman).

What do they do?

Traditional stories (which do not appear on the site you linked) say that these hags are snow predators. They roam through the snow-covered mountains, especially at night or during blizzards. If you are alone or if children play outside on a cold night, they might call out to you or them with an old woman's voice asking for help — but it is a trap. Once approached, they capture and devour children or even unsuspecting adults. Because of this, in some old rural areas, parents were told not to let their children go out during the snow.

This part recalls other legends of mountain hags in Japan, such as the Yamauba, who also attacks travelers and children in the forests — only here it is an icy version of her.

A classic story

One of the recorded versions (in a scroll called Bakemono Emaki from the Meiji period) tells of a man walking through the countryside in the height of winter when he heard an old woman's voice asking for help in the snow. When he approached… a horrible figure appeared hopping on one leg — it was the Yukinba. Terrified, he fled before becoming lunch.

Anthropological Curiosity

The fear of playing or traveling during snowstorms in Japan wasn't just because of the cold — it was also because blizzards were deadly, and people really did get lost or freeze to death. Legends like those of the Yukinba and Yukifuriba functioned as warnings to stay home and stay safe during winter.

Research sources: Hyakumonogatari Kaidankai, Yokai.JP, Yokai.com, SamKalenski