The waterspout appeared, stretching up out of the ocean and seeming to skirt between boats – boats whose situation off the coast of Singapore suddenly looked decidedly more perilous.

The formation of a waterspout off the coast of Singapore.

Bystanders on land watched the towering vortex, awestruck. An eerie howling sound could be heard preceding a burst of heavy rain and extremely strong winds. If people on shore ducked instinctively at this expression of Nature’s power then we can only guess at the reaction of those on the boats as these terrific elements were unleashed. Yet no sooner had the phenomenon started than it ceased, leaving observers gaping at the display they had witnessed.

The cascade of sea spray with the funnel rising skyward to the cloud.

Boats in the vicinity of waterspouts like this must feel vulnerable, to say the least. Though most are less ferocious than tornadoes – their land-based cousins – waterspouts are still serious marine hazards that can wreak havoc when they surprise ships, helicopters, planes and swimmers.

Waterspouts (at least, those classified as non-tornadic) generally begin their life cycle at the water’s surface before climbing up into the sky. They occur in high humidity, when warm water temperatures interact with cold air. Despite what we might perceive, the giant column does not really suck up seawater into its midst; the funnel is technically a cloud, made visible by water droplets formed by condensation.

The funnel appearing to grow in intensity.

The waterspout photographs shown here were taken off the southeastern coast of Singapore, home of photographer Jerry Liew. Liew spotted the waterspouts from the comfort of his apartment, and being so centrally located, he has witnessed quite a few of them over the years. According to Liew, they occur several times a year along Singapore’s coastline.

Even so, there must surely be some good fortune involved in capturing not one but two such series on camera – as Liew managed to do, in 2007 and 2009. Waterspouts often form too far out at sea to be seen from land (although they do generally occur within 60 miles (100 km) of the coast). Add to this the fact that when such an event happens, many bystanders must be simply too awestruck to remember to take out their cameras, and you begin to realize why there are so few amazing image sequences like this one.

The small boat looks as though it is stuck in the sea spray generated by the waterspout.

Though waterspouts occur most frequently in the moisture-laden environments of the tropics, temperate zones further north and south also witness their fair share: the Netherlands, Spain, the UK and Italy report around 100 between them each year, and they are also fairly common over the Great Lakes in North America and the Eastern coast of Australia.

This wide shot shows how two waterspouts can develop from the same cloud.

A waterspout is basically what it appears to be – a tornado over water – though when you investigate them further, the truth isn't quite so simple. While tornados on land tend to be more powerful, one also needs to distinguish between two distinct types of waterspouts – tornadic and non-tornadic.

Non-tornadic waterspouts are also called 'fair weather waterspouts' because of the mild conditions in which they develop. Most waterspouts fall into this category, and generally form along the long, dark bases of developing cumulus towers.

It almost seems as though this waterspout is directly targeting the boat barely visible at the bottom of the picture. The second waterspout on the right appears to be dissipating.

Rarer and more destructive, tornadic waterspouts often start life as land tornadoes before moving out over water. They’re also closely linked to thunderstorms. Because most true tornadoes occur in land-locked regions, tornadic waterspouts are much less common than their fair weather counterparts, though they are more frequent in areas such as the Adriatic, Aegean and Ionian seas, around Italy and Greece, where tornadic waterspouts represent around 50% of those reported.

An image of what looks like a pair of waterspouts in their dying stages. The spout on the left seems to have completely decayed, with the second about to.

Each waterspout goes through five consecutive stages in its life cycle: a dark spot that appears around a bright circular disk on the surface of the water; a light and dark-toned spiral pattern emanating from the dark spot; a dense ring of sea spray comparable to the eye of a hurricane; the funnel, which can be seen rising up several hundred feet or more from the water to meet the mass of cloud overhead; and, after this peak in intensity, finally decay, where the waterspout dissipates as less and less warm air flows into the vortex. By the time you spot a non-tornadic waterspout by its characteristic funnel, it will already have almost reached maturity.

Fair weather waterspouts don’t tend to move much, or if they do, travel slowly.

We asked photographer Jerry Liew if waterspouts were common in Singapore where he lives. “Though not as common as a thunderstorm, when they occur nearer to land such as the ones I saw, they often create a buzz in the community,” he revealed. “Whenever they occur they are almost instantly reported in the local press and the lucky ones who managed to take pictures or videos usually post them in the local forums.” We can imagine – waterspouts must be a truly spectacular natural phenomena to observe!

According to Liew, the waterspouts he has witnessed “create a huge howling sound followed by very strong winds and heavy rain for a short period”. Though this might sound like a frightening prospect, fair weather waterspouts often last for less than 20 minutes – much less than their tornado cousins on land.

Needless to say, never sail, cruise or swim directly through a waterspout. Even those of the non-tornadic variety can cause considerable damage to boats, let alone far more fragile people. According to the National Oceanic and Atmospheric Administration, if you should ever find yourself near to a waterspout, you move at a 90-degree angle to the path it appears to be taking; don’t even think of going in for a closer look; and be ready to seek shelter or safe harbor. Waterspouts may be beautiful and fascinating, but the threat they pose can occasionally match that of tornadoes.

Finally, heed weather warnings – and keep your eyes open! If you notice dark and light disks on the water surface (of the type described above) beneath a dark, flat base of cumulus clouds lined up overhead, you may be witnessing the formation of a waterspout.

However, if you happen to be sure that you’re somewhere safe yet still close enough to witness one of these meteorological marvels, make sure you grab a camera and take as many amazing snaps of the event as you can!