Once autumn arrives we can say that we have safely moved on from the summer rainstorm season. Earlier this year, the Hong Kong Observatory (HKO) issued the Black Rainstorm Warning Signal in March - the first time this has been done in this particular month since the rainstorm warning system was launched in 1992. You might remember the heavy showers of rain and hail pouring down like waterfalls in some shopping malls and railway stations that day. Looking back at the weather between March and August this year, extremely heavy rainfall was recorded in the months of March and May, amounting to more than double the normal rainfall for the period, thus posing huge challenges to our landslide mitigation efforts. Luckily, most of the landslide incidents of the rainy season were minor in nature and did not cause any casualties or serious damage.
However, these minor landslide incidents serve to remind us that we can never let down our guard owing to the unique climate and geographical conditions of Hong Kong. In the 1970s, disastrous landslides caused serious damage to our community. For instance, the fatal landslides on Kotewall Road, Mid-levels and in Sau Mau Ping, Kwun Tong in 1972 caused a total of 138 deaths. Consequently, the Government established the Geotechnical Engineering Office (GEO) in 1977, which is dedicated to slope safety and geotechnical control and tasked with carrying out stabilisation work on existing slopes and examining new slopes.
During more than 30 years of hard work we have substantially lowered the landslide risk of man-made slopes through the Landslip Prevention and Mitigation Programme, alert systems, public education and safety screening of private slopes, as well as by encouraging private owners to maintain their slopes. Nonetheless, the HKO estimates that the frequency and intensity of extreme rainfall will probably increase in future due to climate change. For instance, the HKO issued a total of 41 rainstorm warning signals, including 30 Amber, nine Red and two Black signals, between March and August this year and an accumulated rainfall of 2 300 millimetres was recorded, which is 21 per cent more than the normal rainfall recorded for the same period in previous years. During that period, the GEO issued a total of five landslip warnings through the HKO.
Given the ever increasing risk of casualties and economic loss due to landslides caused by extreme weather, we have to remain highly vigilant. The Government has formulated a set of contingency plans for natural disasters to ensure that all the government departments concerned can deal with emergencies swiftly, effectively and in a co-ordinated manner. Training and operation exercises are organised to ensure that contingency plans can be carried out thoroughly and effectively.
As a frontline department, the GEO provides a 24-hour landslide emergency service and gives professional advice to other government departments on how to handle immediate dangers brought by landslides, such as issuing landslip warnings alerts through the HKO to remind the public of the potential danger of landslides. Thanks to the co-operation of the community and the effectiveness of the landslide emergency services, we have succeeded in reducing substantially the casualties and damage caused by landslides over the past 20 years.
At the same time, the GEO has continued to enhance its emergency preparedness for dealing with severe landslide scenarios. Enhancement measures include the use of modern information technology to provide key information and alert messages, the deployment of dedicated contingency teams to assess the risk of major natural terrain landslides, and assisting other government departments in carrying out landslide emergency works through the GEO’s works contractors.
Despite the enhancements made to landslide emergency preparedness, there is still a limit to the Government’s emergency capacity. It is therefore paramount for the general public to work with the Government in emergency situations by taking the necessary personal precautionary measures. For instance, we should always remain vigilant and heed the warnings and advice issued by the Government during severe rainstorms. When the landslip warning is in force, we should stay away from slopes, stay alert and report any signs of landslide danger. Pedestrians should avoid walking along or standing close to steep slopes, while motorists should also avoid driving in hilly areas or along roads with landslip warning signs. When necessary, it is essential for us to strictly follow the instructions of the rescue personnel and act promptly. If asked to evacuate, we should leave immediately and should not re-enter the areas that have been cordoned off.
As the GEO’s television promotion video says, “Everyone could be in danger if landslide occurs.” The concerted efforts of the Government and the public can help minimise loss of life and damage to property even when we face the risk of landslides during extreme weather. Let us work together to prevent landslides!
2 November, 2014
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