Ex-Tropical Cyclone Alfred caused insured losses of about $1.877 billion, Perils says in its fourth and final estimate on the storm.

The total makes Alfred the “largest insured cyclone loss on an as-if-today basis since Cyclone Debbie in March 2017”, according to the catastrophe data specialist.

Alfred brought heavy rain and flooding to Queensland and NSW after making landfall near the Gold Coast on March 7 last year as a category 1 storm.

Perils says the “combination of long-lasting high winds and heavy rainfall, owing to the storm’s slow forward progress, led to a very high volume of claims”.

Its loss numbers cover the property and motor hull lines of business and are based on information collected from affected insurers.

Personal lines make up 70% of the total loss, commercial lines 26% and motor 4%.

Perils initially estimated the storm’s insured losses at $2.568 billion but lowered the figure in subsequent updates.

“Tropical cyclones typically bring very strong winds and heavy rainfall,” head of Asia-Pacific Darryl Pidcock said.

“In the case of Cyclone Alfred ... wind gusts were not particularly strong and thus the wind alone was not the main loss driver. Rather, it was the mix of prolonged windy weather and heavy precipitation which drove the losses.”

He says Alfred’s “unusual cyclone character made loss reserving challenging and insurers chose a cautious approach in the early stages post-event … Since then, loss development has become much more stable, and losses reduced by a mere 2.3% for our final loss number.”