Emergency services in the ACT are responding to hundreds of calls for help after a severe storm swept across the area last night.
The storm dumped up to 65 millimetres of rain in some areas of Canberra with strong winds and rain causing flash flooding and downing power lines.
Some suburbs in the capital's north are still waiting for power to be restored after 20,000 homes lost power.
Emergency services received more than 400 calls for help, mostly for flooding, fallen trees and leaking roofs.
The priority calls were dealt with overnight and crews will get to work on the remainder today.
The Calvary Public Hospital in Canberra also lost power for about 20 minutes when its backup generator failed to kick in.
Calvary Hospital's director of nursing and midwifery, Kerrie Hayes, says the generator failed because the boiler room flooded.
She says there are always procedures in place if the power fails, but a review of what happened is underway.
"On Tuesday morning when everyone is back at work we will have a formal debrief and a formal review," she said.
"We'll be working on actions to make sure that the next time we have this quick inundation and big storm that flooding doesn't occur and that our auxiliary power kicks in as it's supposed to."
No surgery was being performed at the time and no patients were adversely affected.
© ABC 2013
16:56 EST Last night, as high pressure system was slowly tracked over the state, winds became light and skies clear.