Meteorologists have observed a rare occurrence off Sydney’s coast: an exceptionally long wave period, measuring 22 seconds. This period is nearly three times longer than what is typically expected around this time, and it was recorded 12 kilometres from Freshwater Beach this morning, as reported by Weatherzone.
Common wave periods in the area range from 8 to 12 seconds, and instances of wave periods exceeding 16 seconds are statistically very unlikely, with a 0.8% chance of happening currently. Even longer periods of over 20 seconds occur just 0.004% of the time in any given year—significantly lower than the odds of one being struck by lightning, which stands at about 0.0833%. This particular wave period is among the largest noted since records began at the Manly Hydraulics Laboratory in 1992.
The unusual wave activity is attributed to powerful winds from Antarctica experienced last week, generating a swell that travelled along the New South Wales coastline. Fortunately, as these long wave periods occurred in waters with short wave heights, they are unlikely to pose significant risks to the coastal areas. However, there may be some effects, such as boats potentially drifting from their moorings and anchors, according to Weatherzone experts.
This phenomenon highlights the variability and unpredictability of ocean conditions, reminding coastal communities of nature’s power and the need for preparedness in maritime activities.