SA's big blackout

SA'S BIG BLACKOUT:

* Severe winds and lightning caused major damage to energy infrastructure in SA's mid north including high-voltage transmission lines.

* The damage caused generators across the power network to shut down with the interconnector with Victoria automatically cut to prevent further damage.

* SA Power Networks reports outages to about 200,000 customers with services to be progressively restored, first in Adelaide and then country towns.

* The blackout triggered widespread gridlock on Adelaide roads, with a spate of accidents and forcing police to direct traffic and to urge people to stay home.

* Premier Jay Weatherill said some people could be without power for several hours as services were progressively restored. He urged locals to watch out for frail or elderly neighbours.

* Hospitals and other emergency services were continuing to operate on back-up power.

* The emergency came amid severe weather with an intense low pressure system the worst to blast SA for more than 50 years.

* A flood watch remains in place for the Adelaide Hills and other parts of the state with up to 100mm of rain expected to fall across Wednesday and Thursday.