In November 2021, the Bureau of Meteorology declared that a La Niña event is underway for the 2021-2022 summer period. While the phrase ‘La Niña’ is regularly thrown around, few understand what this weather event actually means for us, and how it is likely to impact the summer ahead. 

 

What is La Niña? 

La Niña refers to a weather event that is a phase the of ENSO (El Niño-Southern Oscillation) climate cycle. ENSO refers to changes that occur to winds and sea temperatures which occur over an irregular period of time. There are three phases of ENSO; La Niña, El Niño and Neutral.  

The neutral phase is defined as being in neither an El Niño or La Niña phase, and is the ‘in-between’ phase. Neutral conditions are classified as ‘normal’ conditions, and while the neutral phase does not bring the same extremes with it that the other two phases do, extreme weather conditions such as droughts and cyclones can still occur. 

The El Niño phase of ENSO involves warmer than usual temperatures, reduced cloud cover and lower than average rainfall. This is due to the weakening of trade winds, which are winds that consistently blow from east to west around the equator. The onset of the tropical storm season generally starts later than usual, and the severity of such storms is generally reduced. However, droughts are more common and can be more severe during El Niño events. 

While an El Niño event is said to be the ‘warm phase’ of ENSO, a La Niña event is generally classified as the ‘cold phase.’ La Niña events usually result in cooler tropical ocean temperatures and cooler daytime temperatures in areas below the tropics. Warm water is pushed by trade winds to the Australian side of the Pacific Ocean. An La Niña event generally causes cooler temperatures which result from increases in cloud cover and rainfall levels. This can reduce the risk of large bushfires occurring during summer, and the extra rainfall can benefit areas that have not received enough rain during the year. 

 


What are the downsides of La Niña weather events? 

La Niña events bring with them an increased risk of widespread flooding due to heavy rainfall. The occurrence of tropical storms such as cyclones and monsoons also increases during a La Niña weather event, which can lead to further flooding, structural damage and threats to community safety. While tropical areas are known to face summer storms, both the intensity and likelihood of such storms can increase to extreme levels during a La Niña, leaving these areas unprepared and more vulnerable than usual. The cyclone and monsoon seasons also tend to begin earlier in the year during a La Niña event compared to a neutral or El Niño event. 

 

Preparing for what is ahead 

While the likelihood of some natural disasters generally increases over the summer period, a La Niña weather event can lead to extreme weather beyond the ordinary. To ensure that your team and your business are effectively prepared, steps must be taken before a disaster occurs, and plans must be in place to guide your team before, during and after a crisis occurs. 

Having all emergency and disaster plans updated to address the extra threats a La Niña event can pose can be highly beneficial, as well as identifying and mitigating risks prior to a natural disaster occurring. Reducing the risk of business disruptions and safety endangerment during a disaster depends on how your business acts before, during and after a crisis occurs. If your organization needs disaster management planning services, contact our knowledgeable and specialized team at Resilient Services today. 

Call us on 0439 005 271 or fill out an enquiry form and our friendly and helpful team will contact you at your convenience. 

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