Bermuda insurers and reinsurers were hit with $3.6 billion in catastrophe losses from worldwide disasters in 2010, according to the National Underwriter (NU) magazine.But the impact was dramatically softened by favourable prior-year loss development which absorbed three quarters of the catastrophe losses.The NU survey focused on 17 US-listed re/insurers active in the Bermuda market. The group had an average combined ratio - indicating the proportion of premium dollars spent on claims and expenses - of 91.5 percent for last year. This marked an 8.9 point deterioration from the previous year.Catastrophe losses for the 16 companies who reported them added 11.2 points to the combined ratio, as events like the earthquakes in Chile and New Zealand, the Deepwater Horizon oil rig loss and fourth-quarter flooding in Australia took their toll.But the release of reserves set aside for prior-year losses was $2.7 billion, which shaved 8.4 points off the combined ratio, and kept the group within profitable territory. A survey of 20 re/insurers by The Royal Gazette last month found that all made a profit despite last year’s catastrophes and the group’s combined net earnings were around $11.7 billion, down nearly 10 percent from 2009.Even before last week’s earthquake and tsunami event in Japan, catastrophe costs for the first quarter of 2011 were already starting to add up. A group of eight Bermuda market reinsurers has issued a range of preliminary losses from this year’s New Zealand quake, Cyclone Yasi and floods in Australia of between $605 million and $865 million.