Winds and a lightning strike from extreme weather brought about by the worst low pressure system to hit South Australia in 50 years forced the shutdown of the entire electricity network.
And that has caused all manner of trouble and inconvenience.
The state of nearly 1.7 million people, was plunged into darkness around 4pm local time.
High winds are being blamed for bringing down transmission lines, and a lightning strike is being blamed for knocking out a substation near Port Augusta.
South Australian premier Jay Weatherill says, in the situation, the system acted as it should.
"This is a major weather event which has knocked out a major piece of infrastructure, and the system has behaved as it's meant to behave, to protect the national electricity market. When there's a dramatic drop in frequency, it runs the risk of damaging power assets across the whole of the network. So, the system operates in this way to shut the system down. And it's now being restored in accordance with those same protocols."
The government says there are no reports of death or serious injury.
There were reports of a number of traffic accidents because of the blackout, and there was peak hour gridlock at some intersections.
All suburban trains were cancelled, although the plan is for them to be working again.
Hospitals have been operating on backup power, and up to 19 people have had to be rescued from lifts.
But South Australian police commissioner Grant Stevens says police are still able to do their job amid the chaos.
"This is clearly a unique situation, and one that has been the subject of discussions and exercising. So whilst this is unusual, we are preparing insofar as that we should be and that we are able to take the necessary action to ensure public safety."
Police say there have been no reports of looting, robbery or the like.
But as people wait for the power to be put back on, questions are already being asked about whether the problem could have been prevented.
Some are pointing at South Australia's reliance on renewable energy as a possible cause of instability.
More than 40 per cent of the state's energy comes from wind and solar power.
Federal environment minister Josh Frydenberg has refrained from pointing the finger directly at renewables but has told the ABC questions have to be asked.
"That does raise questions for the stability of the system, not just for supply, because, when the wind's not blowing and the sun's not shining, electricity is not being generated, but also for the stability of the system because of the frequency that is generated, as opposed to base load power, which has historically been more coal and more gas. So questions are raised by virtue of the increasing amount of renewables. But it has to be underlined that this was a weather event that led to this occurrence. So this major storm damage has led to a number of different events across the system, which presents this blackout."
Mr Weatherill is defending his state's electricity set up.
He says the events would have happened whether the Port Augusta coal-fired power station, which was closed in May, was open or not.
He says critics are just playing politics when they should not be.
"For people to be saying those things without actually being appraised of all the facts demonstrates that people are using this to play politics, rather than actually responding to what is a state emergency that we're trying to respond to. It's regrettable that people would leap to a political criticism at this time."
