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Wynna Wong

Dark clouds gathered and the wind strengthened in Hong Kong on Thursday as Super Typhoon Yagi edged closer to the city.
Although Yagi, which means “goat” in Japanese, is expected to skirt about 300km to the southwest of Hong Kong, its “super typhoon” status prompted experts to warn the public to err on the side of caution.
The Observatory issued the No 8 typhoon signal at 6.20pm on Thursday and it is expected to remain in force until at least Friday noon.
The Post explains potential threats from Yagi, and how Hongkongers should prepare.


1. What are Yagi’s characteristics?
Former Hong Kong Observatory assistant director Leung Wing-mo said Yagi was not expected to calm down any time soon, and might even intensify on Friday due to seawater temperatures in the South China Sea being unusually warm, which helped the typhoon further develop.
Recent atmospheric conditions, including wind shear, were also playing a crucial role in maintaining Yagi’s strength, he said.
Wind shear refers to the changes in wind speed and direction with altitude.
Leung said Yagi was presenting remarkably symmetrical cloud formations as observed from satellite images, which meant the difference between low- and high-level wind speeds was very little, indicating the storm’s structure remained intact and strong.
Additional factors, such as moisture, also contribute to its resilience.
Air currents from the southern hemisphere flowed across the equator into the cyclone, bringing ample moisture that could enhance Yagi’s intensity.




2. How threatening is it?
Leung said Yagi as of Thursday had a centre of maximum sustained winds that had already exceeded 200km/h, making it a super typhoon.
He explained while Yagi was expected to remain “pretty far away” from Hong Kong at a distance of 300km or more, a No 8 signal should still be considered to protect residents, especially those living in eastern areas such as Sai Kung, Tai Po, Heng Fa Chuen and Lei Yue Mun.




3. What makes a super typhoon?
According to the Observatory, tropical cyclones can be sorted into six categories according to the level of maximum sustained winds near their centres.
Storms from 41km/h to 62km/h belong to the lowest “tropical depression” category, while “tropical storms” are 63km/h to 87km/h.
“Severe tropical Storms” have winds of 88km/h to 117km/h, and “typhoons” from 118km/h to 149km/h.
Finally, “severe typhoons” pack winds of 150km/h to 184 km/h and “super typhoons” of 185km/h or above.
The latter two most severe categories were only added in 2009, raising the number of classifications from four to six.

4. What super typhoons have we seen in the past?
According to the Observatory, at least 11 super typhoons have hit Hong Kong since 1956, seven of them, including Yagi, occurring after 2008.
Some memorable super typhoons in recent times include Saola last year, Mangkhut in 2018 and Hato in 2017.
The weather forecaster said from 1956 to 2008, before a “super typhoon” category was added in 2009, 12 tropical cyclones resulted in a No 10 signal. Four of them were technically super typhoons at some point – Wanda in 1962, Ruby in 1964, Rose in 1971 and Hope in 1979.
From 1960 to 2008, 10 per cent of the city’s No 8 signal storms were actually “super typhoons”.

5. What damage did they cause?
Last year’s Super Typhoon Saola prompted the issuance of the No 10 signal for the first time since Super Typhoon Mangkhut in 2018.
The Observatory said Saola rapidly intensified into a super typhoon after forming, peaking at 230km/h in sustained winds on August 30, and made landfall in Guangdong on September 2, causing significant damage across the region.
The storm severely affected the northern Philippines, claiming two lives, while displacing more than 170,000 people in Fujian in mainland China.
Locally, winds reached up to 189km/h, particularly affecting areas such as Waglan Island and Ngong Ping, with flooding in low-lying areas.
The government received reports of at least 86 people sent to hospital, 1,545 fallen trees and two landslides.




The storm’s compact structure and strong winds led to extensive reports of damage, highlighting the ongoing vulnerability of coastal regions to typhoons.
Mangkhut, meanwhile, was the most intense storm in Hong Kong’s recorded history.
Its maximum winds of 250km/h induced a No 10 signal that lasted for 10 hours – the second-longest since World War II.
Mangkhut wreaked havoc on Luzon and in Guangdong province, killing at least 82 people and destroying more than 15,000 homes.
In Hong Kong, maximum gusts exceeded 256km/h as the storm uprooted 1,500 trees and smashed hundreds of windows.
The storm’s rapid movement and unique wind structure resulted in significant effects, especially in the Pearl River Delta region.


6. How should the public prepare for super typhoons?
Hong Kong authorities have urged the public to take immediate precautions when typhoon warnings are issued, including staying informed about potential travel issues via radio, television or the Observatory’s website.
Loose items outdoors should be secured, drains should be cleared, and shorelines should be avoided, while small vessels must seek shelter as soon as possible.
The Observatory also urged people to lock windows and doors and use reinforced shutters if available.
It also advised people to tape up large windows to prevent injury from shattered glass.
Remaining indoors is essential, and people should stay away from exposed windows and loose electric cables.
For stronger storms or those that hit the city directly, residents should be ready for sudden changes in wind direction and prepare emergency kits as well as communication plans.
The Observatory said if a temporary lull of up to several hours occurred when the eye of a storm passed directly through Hong Kong, residents should remain cautious.


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Hong Kong society

What makes Yagi a ‘super typhoon’ and what should Hongkongers expect?

Hong Kong’s Central district on Thursday evening. Photo: Eugene Lee

Saola uprooted hundreds of trees in Hong Kong last year. Photo: Dickson Lee

Leung Wing-mo Photo: Roy Issa

Super Typhoon Yagi: Hong Kong lowers signal to T3 as storm recedes – as it happened

Although winds are expected to weaken, Hong Kong may experience squally showers with violent gusts. Photo: Dickson Lee

Super Typhoon Yagi: Hong Kong’s T8 warning to remain in force until at least Friday noon

The Hong Kong Observatory will issue the T8 signal at 6.20pm. Photo: Sam Tsang

The Observatory has advised outdoor workers to remain vigilant of the weather changes. Photo: Sam Tsang

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Yagi is expected to pass about 300km to the southwest of Hong Kong but that doesn’t mean you should take it lightly, experts warn


Yagi is expected to pass about 300km to the southwest of Hong Kong but that doesn’t mean you should take it lightly, experts warn.


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Super Typhoon Yagi

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Explainer | What makes Yagi a ‘super typhoon’ and what should Hongkongers expect?

Yagi is expected to pass about 300km to the southwest of Hong Kong but that doesn’t mean you should take it lightly, experts warn

1. What are Yagi’s characteristics?