Words by Ben Macartney

For surfers in the East Coast, Christmas holidays are usually tough times. A search of the Coastalwatch archives shows six straight years of surf under three feet between Christmas and New Year. It’s not until you delve back to 2004 that you find a substantial swell – in that instance a solid round of southerly swell that ranged from four to six feet from December 28 through to New Years Eve. But Christmas 2011 different, thanks to a solid week of easterly swell that kicked in across south-eastern Queensland on Christmas Eve and delivered swell the entire East Coast right through to New Years Day.

Cyclone? What cyclone?

The swell followed the development of a tropical low over the northern Coral Sea back on December 18. The Bureau of Meteorology briefly named this relatively weak system Tropical Cyclone Fina by as it reached category 1 cyclone strength early on December 22. However the US meteorological authority tracking the system disagreed with this assessment, deeming it too poorly organised, and hence never referred to the low as a tropical cyclone. But cyclone or not, the system proved a veritable boon for surfers inhabiting the East Coast, particularly across northern New South Wales and south-eastern Queensland.

The Australian Bureau downgraded the System to ex-Tropical Cyclone Fina later on the 22nd as it encountered strengthening vertical wind shear associated with an amplifying upper level trough crossing eastern Australia. However, on Friday the 23rd the low gradually re-intensified as it underwent extratropical transition, tracking south-eastward across the southern Coral Sea into an increasingly favourable position inside our easterly swell window over the Christmas weekend.

The Swell

The deep low reached peak swell generating capacity over this time frame, setting up a broad, gale-force easterly fetch that stretched across the entire southern Coral Sea and northern Tasman in conjunction with a large high pressure system anchored of New Zealand. The low’s slow movement extended the duration of the easterly fetch over the 25S to 30S latitudinal bands, giving rise to a maximum deepwater significant wave height of about 20 feet within relatively close range of the Queensland coast on Sunday.

This culminated in a heavy easterly swell peaking across south-eastern Queensland and far northern NSW at eight to ten feet late on Christmas Day and early on Boxing Day. The swell subsequently filled in southward during Boxing Day, with choppy four to six foot plus sets reported across Port Macquarie and larger six to eight foot surf across locations further north. A similar increase affected Sydney’s exposed beaches, picking up from three to four foot early on Boxing Day to a stronger four and six feet during the afternoon.

A strong southerly change on Monday the 26th kept a lid on wave quality across much of the coast as the swell began to recede, but over the following days ex Tropical Cyclone Fina continued to direct solid easterly and east-southeasterly swell into the New South Wales coast as the system continued its south-easterly track across the Tasman Sea, maintaining a low-end gale-force easterly fetch across its south-eastern flank

“The low reintensified over the eastern Tasman Sea on 27 and 28 December, setting up one last pulse of ESE swell that saw us through to New Years Day.”

The low generated a final pulse of east-southeasterly groundswell on Friday the 30th and Saturday the 31st, mostly ranging from three to four feet through to New Years Eve before easing back into the two to three foot range by New Years Day.