Getting ready
for La-Lina
 First,
we have El-Nino and now comes La-Nina. We know that El-Nino
is characterised by unusually hot and dry weather condition. It brings with
it drought and intense heat which culminated in and over-dry vegetation igniting
into forest and bushfires in some parts of the globe. La-Nina is the
reverse of this condition. La-Nina is characterised by unusually cold
ocean temperatures across the central and eastern equatorial Pacific. It is
expected to bring with it heavy rainfall to the region thus causing extensive
floods in low-lying areas.
Frequency
It occurs roughly half as often as
El-Nino and six major La-Nina events have been recorded in the past fifty years
as indicated below:-
La-Nina Events
1950-1951; 1955-1956; 1970-1971; 1973-1974; 1975-1976; 1988-1989
In La-Nina years, monsoons
are enhanced over Australia/Southeast Asia but the central equatorial Pacific
become drier than normal (the reverse of El-Nino years). It is noted
that a La-Nina does not neccessarily follow hard on the heels of any
current El-Nino. However, it has done so three times in the past 15 years.
The strong El-Nino of 1982-1983 was followed by a weak La-Nina;
the modest 1986-1987 El-Nino preceded a strong La-Nina; and the
moderate but extended El-Nino of 1991-1995 was succeeded by a weak La-Nina.
It has been found that the cyclic
warming and cooling of the eastern and central equatorial Pacific can be linked
to changes to the surface air pressure. In particular, when the pressure measured
at Darwin, Australia is compared with that measured at Tahiti, the differences
between the two can be used to generate an "index" number termed as the Southern
Oscillation Index (SOI). When there is a significantly positive SOI sustaining
for a 6 months, we have a La-Nina (or ocean cooling), but when SOI is
significantly negative for at least 6 months, we have an El-Nino (or
ocean warming).
Impacts of La-Nina on the weather
in Malaysia
In general, slightly above or above
normal rainfall was recorded during the La-Nina events. However, above
normal rainfalls are also recorded in normal years and in certain years the
amount of rainfall can be much higher than that of La-Nina years. Since
La-Nina tends to develop into a full-fledgd event at the end of the year,
the phenomenon generally has a greater impact during the north-east monsoon
months. Moreover, Sabah and Sarawak are susceptible to the influence of La-Nina
because of their being closer to the Indonesian-Australian region which
generally experience the full impact of El-Nino/La-Nina phenomenon.
Current status of the regional
weather
Reports from the Climate Prediction
Centre in the United States of America indicates that El-Nino conditions
has returned to normal in June 1998. Meanwhile, the ocean surface temperature
in the eastern equatorial Pacific, an indicator for the evolution of El-Nino/La-Nina
phenomenon, is observed to have become cooler since mid June 1998. This
suggests that La-Nina is likely to become a full-blown event with moderate/strong
intensity towards the later part of 1998. This La-Nina event is expected
to persist until early part of 1999.
Rainfall in June, July and August
1998 over most parts of Indonesia, Malaysia and Singapore have been close to
or above normal. This is reflective of the normal weather development in the
region following a very severe El-Nino event. The atmosphere tends to
become favourable for more raindays as compared with the usual drier situation
at this time of the year. The current wet condition over Malaysia is not due
o the impact of the presently evolving La-Nina event.
For the Malaysian region, the impact
of La-Nina is only expected to be most clearly seen in October 1998 and
would have more influence on rainfall during the Northeast Monsoon if the intensity
of La-Nina is moderate or strong. In addition, the La-Nina effect
is expected to be stronger over Sabah and Sarawak than Peninsular Malaysia.
Even though La-Nina is likely to develop over the central and eastern
equatorial Pacific, its strength and related impact over the Southeast Asian
region could only be ascertained towards the later part of 1998.
Stage of Preparedness for the
impending 1998-1999 La-Nina
The Malaysian Meteorological Service
has advised that whether in normal conditions or La-Nina event thecountry
can experience heavy rain following an El-Nino episode. As such, all
relevent government agencies should make necessary preparations for floods as
was done in the past.
Since July 199, Malaysian Meteorological
Service (MMS) has given briefing to the Drainage and Irrigation Department (DID)
and other government and state agencies on the outlook of impending La-Nina.
Special meteorological report has been prepared and is now being distributed
to all National Security Divisions at state level and other user agencies. Inside
this special report, expected rainfall amount, number of raindays and sea states
during the period September 1998 to March 1999 are provided for reference by
relevent agencies/parties.
Regional Meteorological Officers,
especially in Sabah, Sarawak, Penang, Pahang, Selangor, Wilayah Persekutuan,
Perak dan Kelantan have already conducted briefings on the impending La-Nina
phenomenon. Meanwhile, MMS has liaised with DID to prepare for the early
convening of all the State Disaster Management and Relief Committee meetings.
Also, MMS will continue to coordinate with the ASEAN Specialized Meteorological
Centre (ASMC) in monitoring closely developments of La-Nina so as to
issue statements whenever necessary.
Preparations are under way to meet
any eventualities posed by the adverse La-Nina weather phenomenon. The
state Disaster Management and relief committee, has activated flood and emergency
operation rooms in all districts in Sarawak. Precautionary measures announced
includes the necessary logistics such as equipment and manpower to handle evacuations
by helicopters from low-lying inaccessible areas of the interior and the despatch
of food and medicine to those areas likely to be affected by floods.
Teamwork
Several departments and agencies
including voluntary organisationa are now geared up to prepare for any emergencies
that may arise.
The Department of Civil Defense (Rescue
991), Sarawak have identified a few areas in the Kuching District which are
prone to flooding. These are Kpg. Pangkalan Kuap, Kpg. Lidah Tanah, Batu 7 -
18 Kuching Serian Road, Kpg. Sinar Budi, Kpg. Segedup, Kpg. Rantau Panjang,
Kpg. Endap Siburan, pg Tabuan Foochow, Lot Penempatan Desa Wira Batu Kawa, Jalan
Stephen Yong and Batu Kitang. According to Major Edwin Noid, Preparations are
under way to tackle the possibility of an impending flood brought about by the
La-Nina weather phenomenon. Steps to be taken include the setting up
of Operation Rooms and Rescue Centres; putting on stand-by 4 wheel-drive vehicles,
motor boats with engines, portable generators, chain saws, communications equipment,
diving gears and last but not least, medical and food supplies.
The Malaysian Red Crescent Society
(Sarawak Branch) has produced a 'survival tip' under its Community Disaster
Preparedness and Emergency Response Programme. Here are some pointers for your
safety.
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