Seroja made landfall south of the town, about 8 p.m. on Sunday, as a category three storm with wind gusts up to 170 km/h.
Kalbarri, which lies 580 kilometres north of Perth, is home to about 1,400 people.
“I’ve never experienced anything in my life like we experienced last night,” resident and caravan park manager Debbie Major told ABC television on Monday.
“It’s only a small town ... half of it has been flattened.”
Reports of property damage and power outages in Kalbarri and Geraldton began to emerge as the storm’s force was felt and residents took shelter by candlelight.
Fallen trees, damaged homes and wrecked fences could be spotted amid the howling wind and rain, footage on social media showed.
The Department of Fire and Emergency Services said on Monday the majority of the more than 150 calls for help so far had come from Kalbarri.
“The whole town has been impacted. Some areas had a greater concentration of damage than others,” resident and Kalbarri State Emergency Service chief Steve Cable told ABC television.
“Some of the older buildings didn’t stand up very well but even some of the modern buildings, they just couldn’t hold.
“Large trees with quite substantial limbs just snapped off like carrots.”
The fast-moving storm later weakened to a category two system as it pushed inland towards Dalwallinu in the early hours of Monday.
It’s now been downgraded to a tropical low and continues to move southeast over the eastern Wheat Belt, southern Goldfields and South East Coastal areas, with wind gusts up to 100 km/h.
In the meantime, emergency crews are assessing the damage in the Midwest Gascoyne with residents being told to remain inside until the all-clear is given.
Western Power said more than 31,500 customers had lost power in Kalbarri, Geraldton, Northampton, Dongara, Port Denison and Mullewa.
“Once the red alert is lifted and it’s safe, our crews will start assessing damage and responding to hazards,” Western Power’s asset operations manager Zane Christmas said.
Power crews had been preparing for Seroja since Friday but the damage caused by cyclones can make access to roads, properties and power infrastructure difficult, delaying repairs.
“Our top priority will be to make hazards safe, then commence restoration work as quickly as possible,” Christmas said.
A red alert remained in place on Monday for coastal areas from Carnarvon to Lancelin, extending to inland areas and towns including Coorow, Carnamah, Dalwallinu, Denham, Jurien Bay, Lancelin, Moora, Paynes Find and Wongan Hills.
Communities in the zone include Geraldton, the shires of Carnamah, Coorow, Chapman Valley, Irwin, Mingenew, Morawa, Northampton, Perenjori, Shark Bay and Three Springs.
