The storms that battered parts of NSW last week are not uncommon and usually do less damage than tropical cyclones, according to Munich Re.

“These types of extratropical cyclones are not unusual,” Head of Geo Risks Research Peter Hoeppe said.

“They normally bring huge amounts of rain, which causes flash floods and strong winds that may cause storm surges along the coastline.”

Professor Hoeppe says data from last week’s storms indicates widespread rainfall of more than 100 litres per square metre, with some areas enduring up to 300 litres per square metre over 24 hours.

“While it is too early to estimate the losses from this storm, events like this one normally do not have the loss potential of large tropical cyclones,” he said.