Waterspout

If you watched the news recently,

there's this water spout thing that has been happening in Singapore for almost two times.

I really thought it was a tornado at first!

So I kinda freaked out thinking that a tornado has attacked Singapore.

But it was a waterspout or know as tornado over water!

Scary eh?

Pictures from: http://www.deviantart.com/deviation/56294991/?qo=3&q=water+spout&qh=boost%3Apopular+age_sigma%3A24h+age_scale%3A5 &

http://singaporeseen.stomp.com.sg/Gallery43.aspx

More info about waterspout

In general, a tornado occurring over water. Specifically, it normally refers to a small, relatively weak rotating column of air over water beneath a Cb or towering cumulus cloud. Waterspouts are most common over tropical or subtropical waters.

If an actual tornado forms over the water, it is referred to as a waterspout as well. However, it is not a true waterspout in its formation.If a waterspout moves onto land, no matter how it formed, it counts as a tornado.A dust devil is different from the above. It is a swirl caused from intense heating, is not connecting to a cloud base, and does not need convective clouds to form.A waterspout sucks water upwards in the swirls.A waterspout forms under relatively benign convection (garden variety thunderstorms, nonsevere). They form in unstable conditions where there is low level convergence (winds coming together). The clashing of warm and cold air creates what is called vorticity (a measure of spin). The upward motion from the convergence stretches this vorticity and causes it to spin faster (like an ice skater bring their arms closer to their body) and creates the vortex. It is a different process of formation than a tornado.
Most importantly,waterspout can eventually became an tornado if it moves from the water to land.Waterspout usually happens 15-30 mins and it's not dangerous.

Hope this help in clarifying some of your doubts!