Residents in northwest Sydney have been hit with nine blackouts in nine weeks following what energy provider Ausgrid has described as some of the worst storms on record.

Cherrybrook residents have been left in the dark for days after 9 power outages hit the suburb in 9 weeks.

Powerful storms which decimated parts of The Hills and Hornsby between December 13 to 16 saw Cherrybrook residents left without power for several days and sparked, what would later be recognised as the start of ‘blackout season’ between December and February.

An Ausgrid spokesman said the storm event was “the second worst storm (the) network has ever experienced in terms of damage to the electricity network”.

Ausgrid workers try to restore power after a fallen tree brought down power lines. Picture: AAP IMAGE / Troy Snook

“There was significant localised damage to the Cherrybrook area, which took several days to repair and restore,” the spokesman said.

“In many cases we had to rebuild the local network from the ground up and install new power poles and restring powerlines.”

Storms through December 20 and January 5 left residents in the dark once again — causing widespread damage across the entire network.

“It is not uncommon to see an increase in vegetation related outages in the days following severe storms, as damaged branches and trees with waterlogged roots can fall,” the spokesman said.

Pedestrians walk through the mess as Ausgrid workers mop up and try to restore power after a fallen tree. Picture: AAP IMAGE / Troy Snook

“Since December 1, there have been 9 outages across our high voltage network which supplies Cherrybrook, Dural, West Pennant Hills and Pennant Hills.”

The spokesman said the power outages were caused by trees falling onto powerlines on three occasions, two lightning strikes, a possum and three other undisclosed faults in the network.

“Ausgrid is currently investigating 3 high voltage powerlines which supply the Cherrybrook area to look at ways we can improve reliability for customers,” he said.

“This investigation is expected to take several months.”

Ausgrid is also undertaking a separate project looking at ways to improve reliability of power in Dural, according to the spokesman.