It was the type of rain that usually accompanies a thunderstorm and could lead to flooding, he said.
There were also 152 lightning strikes during the storm last night.
"That's certainly a lot of lightning for one region," Corrigan said.
A Fire and Emergency New Zealand spokesman said Rotorua crews attended nine callouts in relation to flooding.
That included roads, houses and basements flooding, he said.
Rotorua Lakes Council said they recieved one call about house flooding in Selwyn Rd in Lynmore last night with a further 21 reports about surface flooding and land property flooding at different locations around the city.
The council's Environmental and Infrastructure Solutions deputy chief executive Stavros Michael said 45mm of rain fell in 1.5 hours which put considerable pressure on wastewater pump stations, but there were no overflows.
"Our contractors have been proactively checking areas and clearing debris and this will continue throughout today," he said.
Rotorua Lakes High School has been forced to close for the day due to a power outage. Principal Jon Ward said the outage was probably due to a lightning strike.
Unison relationship manager Danny Gough said at the peak of the storm, 2500 Rotorua homes were without power.
Heavy storms can carry debris, silt, and leaves that can accumulate on top of drains, preventing water from draining. If residents see or have concerns about blocked drains on the road side, they should call the council so a job can be logged to clear the path for stormwater.
When there is surface flooding on roads, people should drive slowly to stop water being displaced from the road onto properties, and for the safety of themselves and others.
Rotorua Lakes Council operations staff attended the following sites last night: • Haynes Cres • Kauri St • Petrie St • Amun Place • Old Taupo Rd • Ranolf St • Devon St and Old Taupo Rd Intersection • Devon St and Lytton St Intersection • Moncur St • Ford Rd and Malfroy Rd Intersection • Suzanne St • Pandora St • Selwyn St • Sunset Rd • Malfroy Rd and Westbrook Ave Intersection • Phobe Place • Old Taupo Rd (Passed onto Higgins as the State Highway contractor) • Malfroy Rd • Devon St West • Homedale St
Council contractors will be undertaking the following work today:
• Inspecting unsealed roads following the heavy rain. These include Millar Road, Lichenstein Rd, Rotoehu Rd, Maleme Rd, Galatos Rd and Kaharoa Rd. • Re-checking all road sites attended last night to make sure grates are clear and there is no debris on the road. • Removing sediment from Clayton Rd that was washed off a driveway. • Checking the McDowell St construction site to make sure it is safe and tidy.