Hundreds of people have been killed and many still remain missing after a tsunami struck the Indonesian island of Sulawesi on Friday, triggered by a powerful earthquake.

A tsunami warning was sent out – lasting just over 30 minutes – but it appears to have drastically underestimated the scale of the tsunami that would follow. So what went wrong?

What actually happened?
A 7.5 magnitude earthquake occurred just off the island of Sulawesi at 18:03 local time (10:03 GMT) on Friday, triggering dozens of aftershocks.

Indonesia’s meteorological and geophysics agency BMKG issued a tsunami warning just after the initial quake, warning of potential waves of 0.5 to three metres.

But it lifted the warning just over 30 minutes later.

Palu – a city in Sulawesi located in a narrow bay – was hit by waves as high as six metres. The surging water brought buildings down and caused widespread destruction. Hundreds of people had gathered for a beachfront festival and it was was a scene of horror as waves powered over the beach – sweeping up everything in their path.

Indonesia’s National Disaster and Mitigation Agency has said that most of the victims in Palu were killed as a result of the tsunami.