Prosper in a dynamic world
Search

What is a waterspout and are they dangerous?

A waterspout was spotted just off the Sydney coast on Sunday. These beautiful and sometimes violent systems are often spotted off the Australian coast at this time of year, so we go through some frequently asked questions about them.

Image: A waterspout spotted off the Sydney Coast on Sunday. It is likely the waterspout is making contact with the water behind the building. Credit @seabz76 Instagram

What is a waterspout?

Waterspouts are a spinning column of both liquid water and water vapour that stretch from water up to a cumulus or cumulonimbus cloud (i.e. clouds that cause showers and/or thunderstorms).

How do they form? 

Waterspouts form when cold air converges over a large body of relatively warm water. Vortices of water and air start spinning up on the water’s surface, caused by an influx of warm air. This spinning grows faster until it has enough momentum to lift a region of water into the air. A cloud of sea spray forms, followed by a thin column of water vapour that connects to the clouds. Because the column is formed by water vapour, parts of the waterspout can become nearly invisible at times.

Video: A waterspout spotted near Darwin early this year. The raised surface of the water can be clearly seen in white. Credit @seabz76 Instagram

Are waterspouts different to tornadoes?

While waterspouts appear similar to tornadoes, the vast majority are non-tornadic and form fundamentally different. Tornadoes form from a supercell cloud and move down towards the surface, and are therefore much stronger, larger and more dangerous than waterspouts. Waterspouts usually produce wind gusts between 80 and 110km/h, while gusts from tornadoes are often above 120km/h and can exceeded 400km/h.

Where and when do they form?

Waterspouts commonly form in the Australian tropics and east coast of Queensland and New South Wales during heavy showers and storms that are just offshore. Near the east coast, waterspouts are most common during February to July, when waters are warm, and the air starts to cool down. In the tropics, they largely occur between November and April during the wet season, and often occur during monsoon bursts.

How dangerous are they? 

Waterspouts pose no real threat to those on the land while they occur, although powerful waterspouts have been known to throw fish and frogs onto the nearby shore. However, on the water, they can be particularly dangerous to boats and people. Their rotation causes thousands of litres of water to be flung into the air, and can easily lift jet skis, small boats, or swimmers. Waterspouts have been known to cripple fleets of boats in the past, like the 1551 Malta Waterspout that killed at least 600 people.

Can more than one waterspout form at a time?

Yes, outbreaks of waterspouts are somewhat common off the east coast of Australia, usually in pairs or triplets. This is possible because waterspouts are small (usually between 30-100m in diameter) and can occur within large regions that meet the same formation criteria. However, a particularly large outbreak occurred off the Mid North Coast of NSW in May 2021, when at least six, but possibly more than 10 waterspouts were spotted off the coast at the same time.

Image: A waterspout outbreak spotted near Taree in May 2021. Credit @Kirrajane00 Instagram. 

Overall, waterspouts are amazing weather phenomena to behold, but are best observed from a safe distance.

DTN APAC has a variety of products to help any marine service, including storm tracking (to keep an eye for possible waterspouts), weather alerting, and wind, wave and tropical cyclone forecasts. To find out more, visit our website or email us at apac.sales@dtn.com.

Latest news

Satisfy your weather obsession with these news headlines from around the nation, and the world.

Possible negative IOD developing this winter

Warm sea surface temperatures near Indonesia are expected to heat up further over winter, possibly triggering a negative Indian Ocean Dipole (IOD) event. What is the Indian Ocean Dipole (IOD)? The IOD is an index that measures the difference in sea surface temperatures across the equatorial Indian Ocean. A negative IOD occurs when cooler-than-average water […]

Hydropower season wimpers to a start

Snow has fallen across Australia’s alpine region, and while it’s only a moderate amount, it’s a start for the peak hydropower season. Australia’s largest resort Perisher was claiming 15cm of settled snow on its snow stake, with slightly lower totals reported at other resorts, after a polar airmass briefly whipped through southeastern Australia on Tuesday […]

Record May rain soaks NT and WA transport and mining – Queensland next in line

Unseasonably heavy rain has drenched parts of northern WA and the NT, with Queensland next in line for soaking rain in the next few days. A deep stream of tropical moisture originating over the Indian Ocean is fuelling a massive northwest cloud band across Australia this week. This thick cloud band has been producing exceptionally […]

Back-to-back large south swells to smash NSW ports

A powerful Tasman low and vigorous cold front are generating two strong south swells that will bring large waves to coastal NSW in the coming days. The satellite loop below shows a deep Tasman low spinning halfway between NSW and New Zealand. The satellite imagery also shows a powerful cold front crossing well to the […]