Understand Tropical Cyclone Wind Signals

What is a Tropical Cyclone? 

A vast area of low pressure extends on both sides of the equator in the tropics. The northeast trade winds blow from the northeast side of this zone, while the southeast trade winds blow from the southeast side.

Warm tropical water heats the air inside this region of low pressure, creating thundery showers as the air rises in separate packages. Although these showers often come and go, occasionally, they congregate to form enormous thunderstorm clusters. A core of low pressure, or depression, forms near the surface due to the passage of extremely warm, humid air that rises quickly.

A number of trigger mechanisms are needed to turn these cloud clusters into tropical cyclones. Such trigger systems rely on many situations being 'correct' simultaneously. One of the most critical factors is a source of warm, humid air from tropical oceans, whose sea surface temperatures typically range around or surpass 27C. 

Another is low wind shear, caused by winds near the ocean surface that blow from various directions, converge and cause air to rise and storm clouds to form. Because of this, the storm clouds may ascend vertically to great heights; they are also far enough from the equator to spin or twist.

Notable Tropical Cyclones in Australia

Tropical Cyclone Wind Signals 

There are five main categories of tropical cyclone wind signals; we will explain each in detail.

Tropical Cyclone Wind Signal 1

Lead Time (Hrs): 36

Winds (kph): 30-60

Potential Impacts of the Wind:

Some homes with relatively light materials or improvised buildings in vulnerable populations have minor damage. A few banana plants have fallen, some are skewed, and the leaves are typically broken.

Tropical Cyclone Wind Signal 2

Lead Time (Hrs): 24

Winds (kph): 61-120

Potential Impacts of the Wind:

Old, decaying schoolhouses, temporary shelters, and other light-material constructions are either unroofed or partially damaged. Many nipa and cogon homes could have a partly or entirely missing roof. Old wooden electric poles are slanted or fallen, and some old galvanised iron (G.I.) roofs may be torn off or blown off. There is some damage to poorly made billboards and signage.

Generally speaking, the exposed neighbourhoods may sustain mild to severe damage from the winds. Most banana plants, a few mango trees, and similar trees are either broken or uprooted.

A few coconut trees may be damaged, while others may be skewed. There may be adverse effects on corn and rice. Trees and vegetation suffered significant damage, with some trees with dense foliage being blown down.

Tropical Cyclone Wind Signal 3

Lead Time (Hrs): 18

Winds (kph): 121-170

Potential Impacts of the Wind:

Old, decaying schoolhouses, temporary shelters, and other light-material constructions are either unroofed or partially damaged. Many Nipa and Cogon homes could have a roof that is partially or entirely missing. Old wooden electric posts are slanted or fallen, and certain old galvanised iron (G.I.) roofs may be ripped off or blown off.

Poorly made billboards and signage may have some damage. A few coconut trees may be damaged, while others may be skewed. Corn and rice might be negatively impacted. Trees and vegetation suffered significant damage, with some trees with dense foliage being blown down.

Tropical Cyclone Wind Signal 4

Lead Time (Hrs): 12

Winds (kph): 171-220

Potential Impacts of the Wind:

Significant damage to light-material structures (up to 75% are entirely or partially destroyed); total failures of roof structures. Numerous medium-sized homes lack roofs; some have fallen walls; doors and windows are severely damaged.

All billboards and advertising have been blown down, and a few homes with premium materials are partially destroyed. Banana plantations are nearly destroyed, and most big trees, including mango and ipil trees, have been chopped down or damaged. Coconut plantations may sustain significant damage, and rice and maise plantations may sustain substantial losses.

Tropical Cyclone Wind Signal 5

Lead Time (Hrs): 12

Winds (kph): More than 220

Potential Impacts of the Wind:

Nearly destruction of light-material constructions, particularly in coastal regions that are severely exposed. Numerous homes and commercial structures have completely failed roofs. The majority of mixed-construction residential and institutional buildings might sustain significant damage.

Communication services and electrical power were significantly interrupted. Every billboard and sign has been blown down—the destruction of banana plantations. Coconut trees are slumped, broken, or uprooted; most tall trees are damaged, uprooted, or defoliated. Few trees and plants make it through.

Considerations When Using the TCWS System

When using the tropical cyclone wind signal system, the following factors need to be taken into account:

The TCWS aims to alert people to the dangers of tropical cyclone-related general wind intensity. Due to natural and artificial obstacles, such as surrounding buildings or the local topography, local winds may be significantly more significant than the overall wind strength over the province or sub-provincial locale indicated by the wind signal. 

For example, local winds are often less in places protected from the direction of the predominant wind and stronger over high land (such as hilly locations) and offshore sea.

Except for Metro Manila, which is grouped under a single wind signal level, a wind signal is typically raised at the level of a province, autonomous component city, or highly urbanised metropolis. Nonetheless, a wind signal may be issued at the city or municipality level if the weather conditions demand it.

The strength, the extent of strong winds or higher, and the predicted direction and speed of movement of the tropical storm at the time of bulletin publication determine the scope and timing of wind signal hoisting. Therefore, the change in the wind signal over a specific location is also determined by any change in the tropical cyclone's movement, strength, or the extent of severe winds or higher.

Even though the tropical cyclone wind signal is a tiered system, wind signal levels can be skipped thanks to the escalation or de-escalation of wind signals. For example, it is possible to upgrade Wind Signal #1 in a specific region straight to Wind Signal #3 without passing Wind Signal #2. However, This is only seen when the hoisted wind signal level over a locality does not quickly alter due to the release of an intermediate tropical cyclone bulletin.

Improvements in objective forecast guidance, operational experiences and challenges faced by typhoon forecasters, feedback from end users and stakeholders, and the adoption of best practices from other tropical cyclone warning centres and regionally accepted operational standards have made the current TCWS system in use since March 23, 2022. 

The Impact of Tropical Cyclones

Tropical cyclones, referred to as hurricanes or typhoons based on geographical location, can inflict catastrophic consequences, predominantly resulting in extensive devastation via powerful winds, intense precipitation, storm surges, flooding, and occasionally tornadoes, culminating in substantial fatalities, property destruction, and infrastructural disruption, especially in coastal regions; the most severe destruction typically arises from the interplay of storm surge and inland flooding.

Principal Effects of Tropical Cyclones:

Storm surge: The most perilous element, wherein winds propel ocean water inland, resulting in flooding, coastal erosion, and damage to structures and infrastructure.

Intense winds can displace trees, damage structures, and induce power failures.  

Intense precipitation may result in inland flooding, landslides, and river overflows.

Coastal erosion: Storm surges and waves can substantially erode coasts, compromising beaches and coastal ecosystems.

Tornadoes: Tropical cyclones can generate tornadoes, hence intensifying destruction. 

Socioeconomic Ramifications:

Fatalities: Immediate fatalities from water, airborne debris, and structural failure.  

Economic losses: Detriment to property, infrastructure, agricultural, and tourism sectors.

Population displacement: Evacuations prompted by storm concerns can disrupt communities.

Health consequences: Elevated risk of waterborne illnesses resulting from contaminated floodwaters. 

Environmental Impacts:

Coastal ecosystems may experience significant degradation due to storm surges and floods. Flooding can adulterate freshwater sources with saline water. Disruption of ecosystems: Harm to flora and fauna populations. 

Cyclone Preparedness and Safety Precautions

You should take action before, during, or after a cyclone. The following are the detailed steps and tips for handling cyclones.

Before the Cyclone

Check with your building control body or local council to find out if your house was constructed according to cyclone requirements. Verify the security of your home's walls, roof, and eaves. With permission from the council, trim trees and branches far from your house. All glass sections should have shutters or metal shutters.

Remove any loose items from your property that can blow about and cause harm or damage in the event of strong winds. Know the closest safe high ground and the safest way to get there in the event of a storm surge, tidal warning, or other flooding.

Assemble an emergency kit including a portable battery radio, flashlight, and extra batteries; water bottles, canned or dried food, and a can opener; matches, a fuel lamp, a portable stove, cooking supplies, and dining utensils; a first aid kit and instruction booklet; waterproof bags; and masking tape for windows, and a portable power supply like Jackery Portable Power Station.

Keep a list of phone numbers for emergencies visible. Verify your neighbours' readiness, mainly if they are newcomers.

When a Cyclone Watch Is Issued

Verify your property again for loose materials and secure (or submerge) any significant, relatively light objects, such as trash cans and boats. Fill automobile gasoline tanks, water containers, and your emergency pack.

Ensure everyone in the house knows the most substantial area and what to do in case of an evacuation or cyclone alert. Tune in to your local TV or radio station for further information and alerts. Verify that your neighbours are prepared and aware of the situation.

The following steps could be necessary, depending on the official guidance given by your local authorities as the situation develops.

Pick up kids from school or daycare and head home if local authorities ask you to.

Park cars with the hand brake engaged and in gear under a sturdy shelter.

Close shutters, board up, or firmly tape all windows. Place wooden or plastic patio furniture in your pool or indoors with other unsecured goods. Lock doors and draw curtains.

Pack an evacuation kit with your emergency kit, which should include warm clothing, necessary prescriptions, infant formula, diapers, valuables, critical documents, pictures, and mementoes in waterproof bags. Large or heavy items can be kept safe in a sturdy cabinet.

Stay inside (and bring your dogs with you). For further information, check your local TV or radio station.

Remain indoors (with your pets). Stay tuned to your local radio/TV for further information.

During the Cyclone

All electrical appliances should be disconnected. Tune in to your battery radio for updates. Stay inside and seek cover in the most substantial area of the structure, such as the cellar, interior corridor, or bathroom, keeping windows well away. Have emergency and evacuation supplies on hand.

Protect yourself with blankets, mattresses, or rugs behind a sturdy table or bench if the structure collapses or clings to a sturdy fixture, such as a water pipe. Watch out for the serene 'eye'. Don't believe the storm has ended because the wind stops; strong gusts will quickly pick up again from a different direction. 

Await the official 'all clear'. If you're driving, stop (use the handbrake and shift into gear), but keep a safe distance from the water and steer clear of any trees, power wires, or streams. Remain in the car.

After the Cyclone

Please wait until it is officially declared safe to walk outdoors. Inspect for gas leaks. Avoid using wet electric appliances. Tune in to the local radio for official warnings and recommendations.

Don't return until instructed if you have to evacuate or have already done so. Don't hurry and take the suggested path. Watch out for damaged buildings, bridges, trees, and electrical lines, and stay out of floods. Observe all caution and refrain from sightseeing. Instead, check on or assist your neighbours.

Jackery Portable Power Stations for Cyclones

Essential services such as illumination, communication, and medical equipment may be at risk without power. A portable power station is necessary in this context. These units guarantee a continuous electrical supply, enabling the operation of essential devices.    

Portable power stations are a great way to prepare for a cyclone or other emergency. Jackery is a well-known global manufacturer of high-quality solar equipment, such as solar generators, solar panels, and portable power stations. Jackery Portable Power Stations offer larger capacities to run home appliances for numerous hours or days.

A Jackery Portable Power Station is a compact, battery-operated apparatus that supplies electricity while travelling. Equipped with AC, DC, and USB connectors, it supplies power to cellphones, laptops, and most outdoor and household gadgets. In contrast to gas generators, it operates silently, produces no emissions, and can be recharged using solar panels, electrical outlets, or automobile chargers.  

Jackery Explorer 1000 Plus

The Jackery Explorer 1000 Plus is a practical selection for cyclone or hurricane preparedness. It offers compactness, versatility, and efficiency, particularly where mobility and rapid charging are critical. This portable device guarantees that vital emergency equipment stays functional and readily available, regardless of your whereabouts.

With an initial capacity of 1264Wh, expandable to 5 kWh, the Explorer 1000 Plus is optimal for powering critical devices during outages, including mobile devices, lamps, and smaller appliances. Its 2000W output, capable of powering 99% of household appliances, allows you to maintain connectivity and comfort during outages.

The Jackery Explorer 1000 Plus portable power station features a 10-year lifespan and a Lithium Iron Phosphate (LiFePO4) battery. It delivers stable voltage and a clean sine wave to safeguard all your electronic devices. Furthermore, the cutting-edge ChargeShield technology and reliable power distribution prevent equipment damage.

Discover unparalleled serenity with our silent, emission-free technology. Participate in transforming sustainability as we proudly introduce the industry's first entirely eco-friendly packaging. Enhance your energy solution with Jackery.

Jackery Explorer 2000 Plus

With an expandable capacity of 2 to 12 kWh, Jackery Explorer 2000 Plus is suitable for unexpected power outages caused cyclones, hurricanes, or storms. It can charge 99% of household appliances and electronics, such as lights, radios, phones, computers, etc. With a 20ms EPS, essential devices such as your refrigerator and CPAP remain operational instantaneously during a power outage.

The Explorer 2000 Plus requires only 6 hours for a complete solar charge when utilising 6 SolarSaga 100W solar panels. The power source achieves complete autonomy by using solar energy for charging, eliminating reliance on the power grid. You can recharge it with a wall outlet (1.7 hours) and carport (25 hours).

ChargeShield is Jackery's advanced quick charge technology, featuring 62 protective mechanisms, 12 protective algorithms, and four forms of physical safety protection. Manage and oversee your 2000 Plus with the Jackery App. It accommodates various devices, facilitates real-time status monitoring, and offers customisation options and additional features.

Tropical Cyclone Wind Signal FAQs

The following are the frequently asked questions about the tropical cyclone wind signal.

1. What is the wind scale for tropical storms?

Very severe cyclonic storms have hurricane-force winds of 64–89 kn (74–102 mph; 119–165 km/h), whereas severe cyclonic storms have 48–63 kn (55–72 mph; 89–117 km/h). Hurricane-force winds of 90–119 kn (104–137 mph; 167–220 km/h) are characteristic of highly severe cyclonic storms.

2. What is the deadliest cyclone in the world?

The world's deadliest tropical cyclone, Cyclone Bhola, which killed up to 500,000 people in what is now Bangladesh, is commemorating its 50th anniversary. It finally formed the groundwork for WMO's Tropical Cyclone Programme and sparked demands for action to stop a recurrence of such a devastating death toll.

3. How are cyclones measured in Australia?

Its average sustained wind speed must be more than 63 km/h to qualify as a cyclone. The average sustained wind speed must be more than 118 km/h to qualify as severe. A cyclone's intensity decreases and starts to fade away as soon as it crosses land.

4. What is the difference between a tropical cyclone and a hurricane?

Depending on where the storm forms in the world, a tropical cyclone is categorised as a hurricane, typhoon, or tropical cyclone after its maximum sustained winds exceed 74 miles per hour or more. The name "hurricane" is used in the North Atlantic, central North Pacific, and eastern North Pacific.

Final Thoughts

A vital part of Earth's atmospheric systems, tropical cyclones are intense and frequently devastating natural events. The risk to life and property can be considerably decreased by being aware of their production, possible effects, and necessary safety precautions. 

Governments and communities may increase resilience and reduce losses by better preparing for these occurrences with enhanced forecasting technologies, such as the Tropical Cyclone Wind Signal (TCWS) system. Awareness, readiness, and adherence to safety procedures are crucial to lessen the destructive consequences of tropical cyclones.