The unknowns of thunderstorm
Thunderstorms are a part of daily life in warm tropical regions like the Philippines. A thunderstorm forms quickly in warm and humid environments, and they normally intensify during the months of April and May. This year, under the prevailing Weak El Niño in the Tropical Pacific, it has been a lot warmer, and several regions of High Pressure zones have moved closer to Luzon’s Western and Eastern coast. Today, we unravel the thunderstorms’ little secrets.
Thunderstorms form when warm, moist air rises into cold air. The warm air becomes cooler, which causes its moisture, called water vapor,’ to form small water droplets – a process known as condensation. The cooled air drops lower in the atmosphere, warms, and rises again.
One key factor during the formation of a thunderstorm is moisture, which causes its humidity levels to go into overdrive. Next is the amount of instability in the atmosphere. The warm air on the ground tends to rise and is denser than cold air. As the sun heats up the globe unevenly, it heats up the ground and becomes less dense. Eventually, when the warm air rises and cools to a point of condensation, a cloud is formed. This is the birth of a thunderstorm.
Another thing that is very important to the development of a thunderstorm is “lift.” There are multiple ways of lifting air into the atmosphere. In the Philippines, it is by way of convection or frontal lifting, and the other one is through “orographic” lifting, which involves hillsides or high mountains that forces air to rise. Once again, as air rises, it cools under pressure to a certain point of condensation.
How does a thunderstorm become severe?
General or local thunderstorms can produce severe weather but are usually short-lived and relatively weak compared to larger thunderstorms. The key factor for longer severe thunderstorm development is ‘’wind shear.” This refers to the change of speed and/or direction of the wind with height. A severe thunderstorm often blows strong wind gusts ahead of the storm.
Hazards posed by thunderstorm
Globally, lightning is a leading cause of injury and death from weather-related hazards. There are cases where people struck by lightning manage to survive, but not without a variety of long-term debilitating symptoms.
A severe thunderstorm can cause powerful winds in excess of 80 kilometers per hour, as well as hail, tornadoes, and the most common of all – flash flooding in low-lying areas, including rough sea conditions. Anyone caught in these life-threatening situations may have a very small opportunity to take cover before it hits.
Here are some practical things you can do in an approaching thunderstorm:
- When thunder is heard from a distance, head indoors;
- If outdoors, look for a sturdy shelter such as building or a car;
- If on a low-lying roadside, find an elevated location. Just six inches of fast-moving water can knock you down, and one foot of moving water can sweep your vehicle away;
- If at sea, stay inside. If swimming on a beach, get to land immediately and find a sturdy shelter or a closed vehicle – never touch anything metal;
- If indoors, avoid running water as electrical charges may travel through the plumbing system;
- Pay attention to alerts or warnings issued by the state weather bureau or relevant organizations;
- Protect your property by unplugging appliances and other electrical devices. Do not use landline phones, including mobile phones.
As the Philippines is known for having vagaries in weather, even the most innocent-looking weather system could inflict such damage to our community and cost us our lives and even our loved ones. With this, we should all be ready not just with our rain gear, but with the mindset that now is the time to be more wary of possible sudden changes in the weather, be it cold or warm, typhoon or not. Stay #WeatherWiser!
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–By Adonis S. Manzan
Typhoon Specialist, WeatherPhilippines Foundation, Inc.