Cyclones, Rainfall and El Nino

Cyclone risk

An El Niño event also has implications for the number, severity and range of cyclones in the current season, particularly for countries in the eastern Pacific such as the Cook Islands and Samoa.

“The warmer than average water further east in the equatorial Pacific Ocean in an El Nino year means that cyclones can form in a larger area, expanding further to the central Pacific. These cyclones tend to spend more time traveling over warm water before reaching land, gathering extra strength along the way,” said Tom DiLiberto, climatologist at the Climate Prediction Center within US National Oceanic and Atmospheric Administration.

The Fiji Meteorological Service predicts that 10-14 tropical cyclones will occur in the region during the the current season. The tropical cyclone risk is highly elevated for Solomon Islands, Wallis & Futuna, Tokelau, Samoa, Northern Cook Islands and French Polynesia. The risk is elevated Vanuatu, Fiji, Niue and the southern Cook Islands. Cyclone activity for New Caledonia, Tuvalu and Tonga is likely to be near normal.  Cyclone activity in the vicinity of Kiribati is unlikely, however all coastal communities need to remain alert and prepared. The Fiji Meteorological Service also predicts there is an increased risk of more severe tropical cyclones affecting the region this season compared to last year.

Cyclone-related rain and El Niño

The kind of rain associated with cyclonic activity in the Pacific Summer will generally only offer a temporary reprieve from long-term drought conditions. This kind of rainfall is usually heavy and short lived. It can cause erosion of drought-degraded soils. The usefulness of the kind of rain will depend on whether it falls in drought-affected locations and/or is captured in fully functioning water tanks or dams.

“During the last week of December and the first week of January 2016 we saw active monsoonal weather around the south Pacific, primarily Samoa, Tonga and Fiji. This rain, while useful for filling up tanks and freshening up gardens, has likely had only minor impacts replenishing groundwater storages,” said Nadraki Weather Meteorologist Neville Koop.

“Overall rainfall amounts remain below to much below average across the region, and now that the rain associated with the recent tropical weather systems has gone, dry weather is expected over most parts of the region once again.”

Peter Sinclair from the Secretariat for the Pacific Community’s Water and Sanitation Programme sounds a similar warning to stay vigilant.

“Regardless of recent rainfall patterns, an El Niño is still present and continues to impact our region’s weather,” he said.

Most outlooks for the region suggest that while the current El Niño may have peaked, there are likely to be continuing impacts. The latest NIWA Island Climate Update Bulletin for January says the region is likely to see continued El Niño impacts for some time yet.

“International guidance indicates that El Niño conditions are certain (100% chance) to continue over the next three month period (January– March 2016). Several indicators suggest that although El Niño may have peaked towards the end of December, it is forecast to remain strong over the next three months then decay rapidly, with a return to neutral or a transition to La Niña conditions by the winter (July – September 2016),” NIWA said.

“Below normal rainfall is forecast for New Caledonia, the southern Cook Islands, Samoa, southern Vanuatu, Wallis and Futuna, Niue, Tonga, Fiji, northern Vanuatu and the Federated States of Micronesia.”

In its latest update, the US National Oceanic and Atmospheric Administration has also indicated that some locations in the republic of Palau, Yap State and parts of the northern Marshall Islands are entering a period of moderate to severe drought conditions typical in connection with an El Niño event.  

Impacts on individual communities will, of course, vary in accordance with local conditions, as well as with the nature of their water source or sources, and with the local practices in place to support resilience at the household and community levels. The relief from rainfall might be greater in some areas than others.

The key message is don’t assume the drought conditions are over just yet.   

“Based upon the available information for the first quarter of 2016, preparedness activities for dry conditions would still be recommended in those countries identified in the seasonal climate outlooks,” Peter Sinclair said.

Some advice about steps you can take to mitigate the impacts of El Niño:

  • For communities with a history of water-related impacts associated with El Niño events, now is the time to prepare for and respond to potentially abnormally drier or wetter conditions (depending upon the typical impact) – at the household, village, island and national levels.
  • Gutter maintenance and water conservation can help ensure that every drop of rainfall is captured and used wisely. Even small reductions in daily water use can help maintain precious rain or groundwater reserves throughout periods of low rainfall.
  • If you don't have a rainwater harvesting system, identify where water runs off your roof and consider what containers (e.g. buckets) you could use to capture some water when it does rain.
  • Fixing leaky taps and pipes, as well as collecting rainwater is critical for farmers to feed their livestock and water their plants, as well as for families to use in washing, cooking and to drink.
  • Maintaining good hygiene practices such as boiling drinking water and hand washing can help avert the worst health impacts of both above and below normal rainfall. Local drought and flood management plans can help clarify roles, keep track of developing conditions, and mobilise responses to those most in need.
  • Where possible, farmers should be planting drought resistant crops which can adapt to survive long periods of dryness. Examples include dalo ni tana, wild yams, African yams, giant taro, cassava, okra (smooth green), moringa and bananas. Trees such as breadfruit, coconut and mango are also drought tolerant.
  • Another possible way to make the most of limited rainfall is through multi-storey cropping system. Land underneath coconut trees is often wasted but it can be used more productively by planting additional crops, growing to different heights with different root systems, providing more diverse food during a drought. For example in dry areas papaya and pineapple can be planted under coconut trees
  • Mulching and drip irrigation are also effective ways of conserving limited water supplies, whilst composting can provide additional nutrients to help plants survive.
  • Watering crops late in the day can also reduce evaporation and the installation of ‘Tippy Taps’ can improve hygiene and reduce waste.
  • There is a chance that fruit trees will fruit heavily as the climate dries further and it would be wise for communities to preserve this fruit for future use so that it does not go to waste.