Tropical Storms (Typhoons, Hurricanes and Cyclones)
Tropical Storms (Typhoons, Hurricanes and Cyclones)
Refer to OM Part C.
Tropical storms are basically the same worldwide. As the intensity of the storm increased, they go under various names in different geographical regions. The term Typhoon applies in the Western Pacific ocean; the term Hurricane applies in the West Indies, Atlantic Gulf of Mexico and Southern USA; Cyclone in the Indian Ocean, the Bay of Bengal and the Arabian Sea and Anticyclone in Southern Hemisphere.
By international agreement, tropical cyclones occurring in the western Pacific and the China Seas are classified according to the maximum sustained wind speeds within their circulations, as shown in the table below.
* The figures in the last column do not form part of the international definitions and are only typical of tropical cyclones experienced near Hong Kong.
Typhoon Categories
Typhoon intensities are measured by the wind speed of the storm according to the Saffir- Simpson Scale.
Category 1
(Minor hurricane/typhoon, 74-95 mph/64-82 knots/119-153 km/h) - No real damage to building structures. Damage primarily to unanchored mobile homes, shrubbery, and trees. Also some coastal road flooding and minor pier damage.
Category 2
(99-110 mph/83-95 knots/154-177 km/h) - Some roofing material, door, and window damage to buildings. Considerable damage to vegetation, mobile homes and piers. Coastal and low-lying escape routes flood 2-4 hours before arrival of centre. Small craft in unprotected anchorages breaks moorings.
Category 3
(Major hurricane/typhoon, 111-130 mph/99-113 knots/178-209 km/h) – Some structural damage to small residences and utility buildings with a minor amount of curtainwall failures. Mobile homes are destroyed. Flooding near the coast destroys smaller structures with larger structures damaged by floating debris. Terrain continuously lower than 5 feet ASL (at sea level) may be flooded inland 8 miles or more.
Category 4
(Severe hurricane/typhoon, 131-155 mph/114-135 knots/210-249 km/h) – More extensive curtainwall failures with some complete roof structure failure on small residences. Major erosion of the beach. Major damage to lower floors of structures near the shore. Terrain continuously lower than 10 feet ASL (at sea level) may be flooded requiring massive evacuation of residential areas inland as far as 6 miles.
Category 5
(Severe hurricane/typhoon, 155+ mph/136+ knots/250+ km/h) - Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. Major damage to lower floors of all structures located less than 15 feet ASL (at sea level) and within 500 yards of the shoreline. Massive evacuation of residential areas on low ground within 5 to 10 miles of the shoreline may be required.
Typhoon Policy and Procedures
The decision for the flight to be delayed or to proceed to the destination, affected by the tropical storm shall be made by Operations Control Centre. Assessments for operations into these areas are reported to the Flight Operations Manager or his designate.
Operation into and out of the affected aerodromes is not recommended when the average winds are above 42 knots.
The Commander of the aircraft that has been diverted to an alternate aerodrome must keep a constant communication with OCC via any available means possible regarding the typhoon conditions.
If an aircraft is grounded at the affected station, the Station Manager and the aircraft Commander will make joint consultation and agreement on an appropriate line of action to safeguard the aircraft.
The cancellation of a typhoon warning is issued by the appropriate aviation authority.
Refer to OM Part C.
Tropical storms are basically the same worldwide. As the intensity of the storm increased, they go under various names in different geographical regions. The term Typhoon applies in the Western Pacific ocean; the term Hurricane applies in the West Indies, Atlantic Gulf of Mexico and Southern USA; Cyclone in the Indian Ocean, the Bay of Bengal and the Arabian Sea and Anticyclone in Southern Hemisphere.
By international agreement, tropical cyclones occurring in the western Pacific and the China Seas are classified according to the maximum sustained wind speeds within their circulations, as shown in the table below.
* The figures in the last column do not form part of the international definitions and are only typical of tropical cyclones experienced near Hong Kong.
Typhoon Categories
Typhoon intensities are measured by the wind speed of the storm according to the Saffir- Simpson Scale.
Category 1
(Minor hurricane/typhoon, 74-95 mph/64-82 knots/119-153 km/h) - No real damage to building structures. Damage primarily to unanchored mobile homes, shrubbery, and trees. Also some coastal road flooding and minor pier damage.
Category 2
(99-110 mph/83-95 knots/154-177 km/h) - Some roofing material, door, and window damage to buildings. Considerable damage to vegetation, mobile homes and piers. Coastal and low-lying escape routes flood 2-4 hours before arrival of centre. Small craft in unprotected anchorages breaks moorings.
Category 3
(Major hurricane/typhoon, 111-130 mph/99-113 knots/178-209 km/h) – Some structural damage to small residences and utility buildings with a minor amount of curtainwall failures. Mobile homes are destroyed. Flooding near the coast destroys smaller structures with larger structures damaged by floating debris. Terrain continuously lower than 5 feet ASL (at sea level) may be flooded inland 8 miles or more.
Category 4
(Severe hurricane/typhoon, 131-155 mph/114-135 knots/210-249 km/h) – More extensive curtainwall failures with some complete roof structure failure on small residences. Major erosion of the beach. Major damage to lower floors of structures near the shore. Terrain continuously lower than 10 feet ASL (at sea level) may be flooded requiring massive evacuation of residential areas inland as far as 6 miles.
Category 5
(Severe hurricane/typhoon, 155+ mph/136+ knots/250+ km/h) - Complete roof failure on many residences and industrial buildings. Some complete building failures with small utility buildings blown over or away. Major damage to lower floors of all structures located less than 15 feet ASL (at sea level) and within 500 yards of the shoreline. Massive evacuation of residential areas on low ground within 5 to 10 miles of the shoreline may be required.
Typhoon Policy and Procedures
The decision for the flight to be delayed or to proceed to the destination, affected by the tropical storm shall be made by Operations Control Centre. Assessments for operations into these areas are reported to the Flight Operations Manager or his designate.
Operation into and out of the affected aerodromes is not recommended when the average winds are above 42 knots.
The Commander of the aircraft that has been diverted to an alternate aerodrome must keep a constant communication with OCC via any available means possible regarding the typhoon conditions.
If an aircraft is grounded at the affected station, the Station Manager and the aircraft Commander will make joint consultation and agreement on an appropriate line of action to safeguard the aircraft.
The cancellation of a typhoon warning is issued by the appropriate aviation authority.
Tropical Storms (Typhoons, Hurricanes and Cyclones)
Reviewed by Aviation Lesson
on
2:59 PM
Rating:
Reviewed by Aviation Lesson
on
2:59 PM
Rating:
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