Sachin Shankar Yadav A severe thunderstorm warning is a formal notification from meteorological organizations to the public that a dangerous thunderstorm is approaching or has already occurred in a particular area. The storm has formed and is producing—or is very likely to produce—one or more of the following, according to this warning:
- Wind gusts that cause damage (usually greater than 58 mph or 93 km/h)
- Large hail, with a diameter of at least 1 inch or 2.5 cm
- Flash flooding due to torrential rains
- The possibility of tornadoes (although not all severe thunderstorms result in tornadoes).
| Alert Type | Definition | Recommended Action |
| Severe Thunderstorm Watch | Conditions are favorable for severe thunderstorms to develop. | Be prepared and monitor |
| Severe Thunderstorm Advisory | Weather may be inconvenient or hazardous; storms not fully developed. | Exercise caution and review preparedness |
| Severe Thunderstorm Warning | A severe thunderstorm is occurring or imminent, based on detection by radar or by trained spotters. | Take immediate shelter |
When meteorologists detect a thunderstorm that satisfies the following minimal requirements using radar or ground reports, a warning is usually issued:
- Winds exceeding 58 mph (93 km/h)
- Hail with a diameter of at least 1 inch (2.5 cm)
- any of the aforementioned, occasionally accompanied by severe lightning and the possibility of flooding.
Each country may have different requirements. For instance:
- UK: hail exceeding 2 cm, winds exceeding 55 mph (89 km/h)
- Australia: heavy rainfall/flash flooding, hail exceeding 2 cm, or winds exceeding 56 mph (90 km/h).
- New Zealand: tornadoes, rainfall at least 25 mm/hr, winds of 68 mph (110 km/h), and hail exceeding 2 cm.
- As soon as possible, seek cover away from windows in a strong building.
- After the last thunderclap, stay inside for at least half an hour.
- To reduce the chance of electrocution during lightning strikes, stay away from running water and electrical appliances.
- Furniture and other loose items should be secured outside as they can turn into projectiles during strong winds.
- To prevent hail damage, move your car under cover.
- Use a television, smartphone app, or radio to stay up to date on weather updates.
Strong thunderstorms may result in:
- extensive hail and wind-related damage to crops and property
- Death or serious injury brought on by falling objects, collapsed buildings, or lightning strikes
- Flash flooding can quickly inundate low-lying areas and carry away people or cars.
- Media broadcasting (radio, television)
- SMS alerts and weather apps
- Sirens (in certain areas)
- official government channel.
It is essential to have an emergency plan, keep an emergency kit on hand, and understand how your local alert system works if you live in an area that frequently experiences severe thunderstorms.
“A Severe Thunderstorm Warning means that a thunderstorm has formed that meets the criteria for being defined as severe. This means that the storm contains either damaging wind gusts in excess of 58 miles per hour or hail at least one inch in diameter or both. A warning is typically issued over a relatively small geographic area in advance of an existing storm. If a warning is issued, it is best to seek shelter in a sturdy structure, away from windows.”