Thunderstorms are severe local storms of short duration, occurring over small area but violent causing significant harm to lives and infrastructure.
About Thunderstorms
- They are well grown cumulonimbus clouds producing thunder and lightning, caused by intense convection on moist hot days.
- They fall in category of Meso-gamma weather systems with spatial extent of around 2~20 km and temporal scale of few hours.
- Types: Considering their intensity, the thunderstorms in India are categorised as
- Moderate: Loud peals of thunder with associated lightning flashes, moderate to heavy rain and maximum wind speed of 29 to 74 kmph.
- Severe: Continuous thunder and occasional hailstorm, and maximum wind speed exceeding 74 kmph.
- Occurrence: Frequency and intensity are maximum during summer months (March to June) due to intense heating up of atmosphere at surface level.
Life Cycle of Thunderstorms
- Developing Stage: Marked by cumulus cloud being pushed upward by a rising column of air (updraft); that soon looks like a tower.
- This stage has little to no rain but occasional lightning.
- Mature Stage: While Updraft continues to feed the storm, precipitation begins to fall out of the storm, creating a downdraft (column of air pushing downward).
- Causes hail, heavy rain, frequent lightning, strong winds, and tornadoes.
- Dissipating Stage: Eventually, large amount of precipitation is produced and the updraft is overcome by the downdraft beginning the dissipating stage.
NDMA through its Guidelines for Prevention and Management of Thunderstorms, 2018 provide comprehensive measures to tackle it by way of Hazard mapping, structural mitigation measures, etc.
