Power was yet to be restored to about 29,500 homes and businesses late on Tuesday as authorities continued to assess the damage from the devastating storm.
Western Power said there were outages across the Midwest and Central Wheatbelt in an area more than 700km long and 150km wide.
About 130 poles have been damaged on the transmission side of the network alone.
"We're working steadily to restore power but anticipate that some affected areas will be without power for weeks," the utility said.
"We're working alongside emergency services and other state government agencies to ensure the community has safe access to power as soon as possible."
The transmission line that feeds Geraldton is expected to be energised on Wednesday, allowing the utility to restore power to about 20,000 homes and businesses in the area.
But "significant" repair work is needed in towns north of Geraldton including Kalbarri, Northampton, Horrocks and Port Gregory before power can be restored there.
The premier and key emergency services personnel toured affected regions on Tuesday, including Kalbarri.
Up to 70 percent of properties in the popular coastal tourist town, 580km north of Perth, are thought to have been damaged by the cyclone which hit late on Sunday as a category three storm with winds up to 170kmh.
Mr McGowan said the devastation was readily visible from the air, with buildings, businesses and farms damaged and power poles snapped off.
"It shows the enormous power of the cyclone," he said.
"This was the one in 50-year event, an extraordinary cyclone which caused massive amounts of damage throughout this community and throughout this region.
"We are very fortunate that in the course of this cyclone, there was no serious injury or death."
Evacuation centres are open in Shark Bay, Dongara and Geraldton and army reservists are assisting State Emergency Service volunteers.
The Australian Defence Force has provided a C-130J Hercules aircraft for medical evacuations and to transport emergency workers and supplies.
Mr McGowan said the clean-up would take a "massive effort" but the people of the region were extremely resilient and were dealing with the disaster in good spirits.
"Clearly it has been a very difficult and devastating experience for many people," he said.
"Obviously the reconstruction will take some time, we will work with the commonwealth government, the local government, the emergency funding that will need to be provided to restore particular public assets.
"I ask people to be patient, it will take some time, the devastation is quite extraordinary."
Tourists have been asked to steer clear of the area where the combined state and federal disaster relief is expected to exceed the $18 million spent on the Wooroloo bushfires which destroyed 86 homes northeast of Perth in February.
