Regarding the continuous appearance of hail in recent times, Mr. Nguyen Van Huong - Head of Weather Forecasting Department, National Center for Hydro-Meteorological Forecasting, Department of Hydro-Meteorological Forecasting - has provided opinions on this phenomenon.
Consecutive avalanches in many localities are rare.
Mr. Nguyen Van Huong, how do you assess the nature of thunderstorms and hail in recent days in many localities in the North and North Central regions?
- On April 2-4, 2026, thunderstorms, tornadoes, lightning and especially hailstorms have caused heavy damage in many localities in the Northern and North Central regions, especially the northern mountainous provinces.
According to recorded data as well as updated reports from localities, only in the late afternoon and night of May 2, thunderstorms, tornadoes, and hailstorms occurred in Dien Bien, Lai Chau, Lao Cai, Tuyen Quang, Phu Tho, Thai Nguyen provinces and Hanoi capital. In the late afternoon and night of May 3, Nghe An and Ha Tinh provinces also recorded thunderstorms, lightning and hailstorms.
In addition to thunderstorms, tornadoes, and hail, also in the period from the evening of May 2 to this morning May 4, widespread thunderstorms occurred in the Northern and North Central provinces, locally there were heavy to very heavy rain points such as: Tan Pheo station (Phu Tho) 171mm, Lam Thao (Phu Tho) 168mm, Ky Giang (Ha Tinh) 156mm, ...
Usually, thunderstorms and lightning storms appearing during the interseasonal period (April and May and the period of October-October) in the northern provinces are not unusual and not uncommon.
For the period in early May 2026, according to preliminary assessments, the phenomenon of hail rain appearing concentratedly in both mountainous, midland and delta areas is rare.
What are the causes of ice rain in recent days and can you explain the mechanism of ice rain formation?
- The phenomenon of large ice rain, with ice particles the size of a chicken egg or tennis ball, occurring in recent days in provinces such as Phu Tho and Thai Nguyen may be due to the fact that in recent days, this area has continuously maintained a hot and humid state, with daylight, accumulating convection energy in the atmosphere.
Above, there is a low pressure trough in the strong westerly wind zone at an altitude of about 5000m; at the same time, in the north, there is a weak cold air mass moving southward, compressing the low pressure trough through the North.
In the afternoon, due to rising temperatures, hot and humid air mass is pushed up strongly, forming thunderstorm clouds that develop very quickly vertically. It is in this highly unstable environment that the upward air flow is very strong to hold the ice blocks in the thunderstorm clouds longer and make them grow larger before falling down. These ice particles, if dissolved into water before reaching the ground, will form normal rains, and if they do not dissipate in time, they will form ice rains.
New cold air wave is about to appear, risk of extreme rain
Is it possible that extreme rains will still occur in the near future, sir?
- It is forecasted that around May 8-9, there will be another new cold air wave, so around the end of this week, the North will continue to have thunderstorms and will face the risk of tornadoes, whirlwinds; hail and strong gusts of wind.
In addition, around May 5-7, there is also a possibility of widespread showers and thunderstorms in the southern Central Highlands and Southern regions. Rain concentrates from afternoon to evening. In thunderstorms, vigilance is also needed against thunderstorms, hail and strong gusts of wind.
Can you recommend some signs to recognize the risk of ice rain?
- Regarding the signs to recognize when ice rain occurs, ice rain is a very small-scale phenomenon often accompanied by strong thunderstorms during the transitional period. ice rain is often accompanied by quite characteristic signs that people can proactively recognize, such as strong thunderstorm clouds appearing in the sky, air transitioning from hot and humid to cool very quickly, strong gusts of wind, heavy showers accompanied by thunder.
When these signs appear, people should quickly find safe shelter, avoid staying outdoors or under large trees.
Thank you very much, sir!
