The phenomenon of a strange vapor trail along the horizon in Hau Loc District is explained as being caused by aircraft engine emissions.
On the morning of December 26, fishermen along the coast of Hau Loc District (Thanh Hoa) and many other places witnessed a bright white streak in the sky near the horizon. Many curious onlookers came to see, take photos, and film videos, believing this to be a natural phenomenon signaling good fortune.
Residents of Hau Loc, Thanh Hoa recorded the scene of the vapor trail from the aircraft engine they witnessed early in the morning. (Video: Provided by locals)
According to Dr. Nguyen Ngoc Huy, a meteorological and climate change expert, this is not a natural phenomenon. The funnel-shaped streak in the sky is caused by a jet engine that may be conducting a mission or training early in the morning.
Dr. Huy explained that when an aircraft suddenly accelerates while moving slowly, it creates a strong compressed airflow. When this airflow is released into the air and encounters the sudden cold from the environment, it causes a quick temperature difference that condenses the water vapor. This results in a visually striking vapor trail, leading many to believe it is a natural occurrence.
According to Dr. Huy, the shape of the vapor trail created by the hot air from the engine operates in a horizontal funnel mechanism, meaning that air spreads out from the center to both sides, creating a similar shape. The shape of the trail depends on the operational state of the aircraft engine.
The expert noted that the vapor trail phenomenon during aircraft operation only occurs when the aircraft suddenly changes speed in regions with low ambient temperatures, specifically at or below 0 degrees Celsius, and when there is no strong wind.
Dr. Huy also mentioned that a similar phenomenon occurred in South Korea at the end of last year, but the vapor trail was vertical due to the exhaust from a rocket interacting with the air, similar to the aforementioned mechanism.
Funnel-shaped vapor trail from an aircraft engine. (Photo: Provided by locals).
Agreeing with this assessment, Master Le Dinh Quyet, Deputy Head of the Southern Regional Meteorological Center, stated that it is highly likely caused by a jet aircraft due to the movement at the tip of the cone-shaped trail. “This is not a natural phenomenon,” Quyet said.
The northern and central regions are currently experiencing the coldest spell of the year due to a cold front. The temperature in Fansipan (Lao Cai) dropped to -3 degrees Celsius yesterday, resulting in frost. According to the National Center for Meteorological Forecasting, starting today (December 26), the cold air will weaken, and temperatures in the north will gradually rise. In Hanoi, temperatures are expected to range from 10-22 degrees Celsius, with daytime temperatures rising to 25 degrees Celsius and nighttime temperatures reaching 17-18 degrees Celsius. At altitudes above 1,600 meters above sea level, such as in Sa Pa, temperatures will increase from 3-12 degrees Celsius to 6-18 degrees Celsius.
