Core Viewpoint - The phenomenon referred to as "Hai Hao" is actually a type of evaporation fog, not a new atmospheric phenomenon, resulting from a significant temperature difference between cold air and warmer water surfaces [4][9]. Group 1: Definition and Origin - "Hai Hao" is a term that originated from local dialects in Dalian, first reported in November 2015, and is not officially documented [4][7]. - The term describes a natural occurrence where cold air flows over warmer water, leading to the formation of fog [9]. Group 2: Weather Conditions and Occurrences - The phenomenon has been observed in various locations, including Changbai Mountain, Qingdao, and Dalian, particularly during cold weather conditions [4][5]. - Specific weather conditions necessary for the formation of this fog include a temperature difference of over 20°C between the air and water [8][9]. Group 3: Expert Insights - Experts from the Ocean University of China emphasize that "Hai Hao" is not a new atmospheric phenomenon but rather a well-known occurrence of evaporation fog under specific climatic conditions [6][9]. - The phenomenon is likened to the steam rising when boiling water, illustrating the visual similarity of the fog formation [9].

Core Points - A strong cold air mass has swept across most parts of China since October 15, with temperatures expected to gradually rise after October 22, although it will still feel cool, necessitating warm clothing [1][3] - Snowfall occurred in Laiyuan County, Baoding, Hebei, with the lowest temperature dropping to 0°C, causing slippery roads and cautious driving [3] - Shanxi Province issued blue frost warnings, with temperatures in cities like Datong and Taiyuan also dropping to around 0°C, prompting agricultural departments to prepare for frost and protect crops [5] - In Jilin's Changbai Mountain, a rare natural phenomenon called evaporation fog was observed due to sudden temperature drops, creating a visually striking scene [7] - Zhejiang experienced a rapid temperature drop due to the cold air, with minimum temperatures falling to 13-15°C and strong winds causing a noticeable wind chill effect [9] - The upcoming frost descent on the 23rd marks a climatic turning point, with experts warning that blood pressure may rise, particularly among hypertensive patients, due to cold-induced vascular resistance [11]