The climate of the east coast of NSW is distinct from the rest of the state due in large part to East Coast Lows.
East coast lows (ECLs) are intense low-pressure systems that occur off the east coast of Australia. They can form at any time of the year and significant ECLs occur on average about 10 times each year. These storms can bring damaging winds and surf and heavy rainfall. They can cause coastal erosion and flooding. But while they can be costly storms, they are also important for water security bringing the heavy soaking rainfall that fills dams along the coast and the Tablelands.
ECLs produce nearly a quarter of all rainfall along the coast and are responsible for about 40 per cent of the heavy coastal storms we see. Nearly 80 per cent of the extreme rain events on the Central Coast of NSW are due to ECLs. For Sydney, the Warragamba catchment often replenishes in bursts from extreme rainfall events such as ECLs. These storms account for over 60 per cent of the high flow events to catchments in the Sydney region. However the water security benefits of ECLs are not limited just to the coast, large ECLs can also bring significant rainfalls to the headwaters of rivers flowing westward, delivering water to the inland of NSW.
East coast lows can intensify quickly and can pose considerable risk to shipping. They are often associated with turbulent seas and strong swells and have led to many significant shipping accidents – for example the stranding of the Pasha Bulker on Nobby’s Beach in June 2007 and the wrecking of the MV Sygna on Stockton beach in May 1974.
Pasha Bulker, Newcastle
Flash flooding, river flooding and coastal inundation can occur due to ECLs. Fast flowing and fast rising flood waters, fallen trees and severe seas can be very dangerous and lead to tragic loss of life. The Pasha Bulker storm of June 2007 caused at least 9 deaths and $1.5 billion in damage.
A decade or more ago, ECLs could not be forecast more than a day ahead, however, with improvements in forecast models, ECL can now be predicted with confidence at least four days ahead, although some uncertainty may remain in the precise location and intensity of the storms. This early identification of ECLs allows emergency services and communities to better prepare ahead of the potentially hazardous impacts of these powerful storms.
Since ECLs can have such large effects along our coast, it is important that we have a good understanding of how these storms have changed in the past, how they affect us now and how they may change in the future. This information will allow emergency management groups, catchment managers, coastal planners and other agencies to better plan for the impacts of ECLs along the NSW coast.
New research is being delivered to better understand: