雲仙の冬。 仁田峠、妙見岳、国見岳、普賢岳などの標高1,100メートル以上の地域では、12月から3月にかけての厳冬期に霧氷が見られます。特に寒い日には、月に10日～12日ほど霧氷が見られます。
数十年前は寒さが厳しかった頃は温泉街でも霧氷が見られましたが、近年は地球温暖化の影響か、霧氷を見る頻度が減ってきました。
霧氷は、北風に吹かれて木の枝にできる氷の結晶です。それらは冬の気圧システムによって形成され、西の高気圧と東の低気圧、雲、霧、および氷点下で発生するその他の要因があります。
地元では「花ぼうろ」とも呼ばれ、住民に愛されています。ちなみに、東北の蔵王地方で見られる「樹氷」は、雲仙の霧氷とは違います。雪が枝にくっついて凍結することで形成されます。

Winter in Unzen. In regions with elevations exceeding 1,100 meters such as Nita Pass, Mt. Myokendake, Mt. Kunimidake, and Mt. Fugendake, you can observe rime ice during the severe winter period from December to March. Especially on extremely cold days, rime ice can be seen approximately 10 to 12 days per month.
Several decades ago, during times of more intense cold, rime ice was also visible in the hot spring town. However, in recent years, possibly due to the effects of global warming, the frequency of observing rime ice has decreased.
Rime ice is formed by ice crystals that develop on tree branches when blown by the north wind. They are created through the winter pressure system, influenced by the high-pressure system in the west, low-pressure system in the east, clouds, fog, and other factors occurring below freezing temperatures.
Locally, it is also known as "hanabouro," and is cherished by the residents. By the way, the "juhyo" seen in the Zao region in Tohoku is different from Unzen's rime ice. It forms when snow sticks to branches and freezes.