“The meteorological sector has never recorded hail in Ho Chi Minh City in August,” said Mr. Le Dinh Quyet, Deputy Head of the Forecasting Department at the Southern Hydro-Meteorological Center.
On the evening of August 22, hailstones the size of three fingers fell in various locations in Ho Chi Minh City, Dong Nai, and Binh Duong. Not only hail, but also thunderstorms and tornadoes were reported in Ben Tre, Mr. Quyet confirmed, adding: “This is also a rather rare phenomenon for the Southern region. Unusual phenomena due to the impact of climate change and extreme weather and hydrological conditions are occurring more frequently and becoming more complex, breaking conventional patterns.”
Hail falling on the streets of Thu Duc City. (Video: Provided by a reader).
He explained that the hailstorm was caused by a subtropical high-pressure system moving westward, pushing a large amount of moisture from the sea inland, while the high pressure also created sunny weather with high air temperatures. With high humidity and temperature conditions, the atmosphere becomes highly unstable and turbulent, with an upward air movement (updraft) carrying warm, moist clouds very high, surpassing the troposphere. The higher the altitude, the lower the temperature; at 0 degrees Celsius, water vapor condenses (freezes), and when the particles grow large enough to overcome gravity, they fall to the ground, resulting in hail.
“The hail phenomenon on August 22 was quite unusual. Hail typically occurs in the Southern region at the beginning and end of the rainy season (May, June, and late October),” Mr. Quyet noted. Each year in the Southern region, hail occasionally occurs in areas such as Dong Nai, Binh Duong, Binh Phuoc, Long An, etc. The most recent event was on July 19 in Tan Binh, where hail fell, but the duration was short and the hailstones were small.
Hail occurred in Ho Chi Minh City on the evening of August 22. (Photo: Southern Hydro-Meteorological Center)
At the end of August and into September and October, the rainy season peaks in the Southern region. The Deputy Head of Forecasting indicated that forecast data suggest heavy rains could accumulate to several hundred millimeters within a few hours. Heavy rainfall is expected to cause urban flooding, along with more frequent thunderstorms and tornadoes. In October and November, when typhoons and tropical depressions operate at lower latitudes, their circulation will also affect southern provinces. Towards the end of the year, wind patterns shift (with southwest winds decreasing and being replaced by northeast winds), and these changes often lead to thunderstorms, tornadoes, and gusty winds.
Meanwhile, accurately predicting hail and the areas where hail will occur in advance “is very difficult,” said Mr. Nguyen Van Huong, Head of the Climate Forecasting Department at the National Hydro-Meteorological Center. The Meteorological Agency can currently only rely on the development of thunderstorm clouds to issue warnings 1-2 hours before hail occurs.
According to Associate Professor Dr. Pham Duc Thi, former Head of the Short and Long-Term Forecasting Department at the National Hydro-Meteorological Center, the manifestations of climate change are becoming increasingly evident. Areas that have never seen snow, such as Nghe An and Ha Tinh, have experienced snowfall in recent years. Record heatwaves are continuously being set, with temperatures in the following year higher than the previous year. “Globally, climate change is rampant, with some regions experiencing extreme heat while others face record cold. The unusual hail phenomenon in Ho Chi Minh City is not outside that pattern,” said Dr. Thi.
“We must prepare for the worst-case scenarios to cope with extreme weather phenomena,” Dr. Thi emphasized, noting that these unusual events have already occurred and will continue to repeat.
