Hurricane Irene is unlikely to be a market-turning event as early estimates of losses begin to come in.

The first hurricane to make landfall on the US coastline in three years is estimated to have caused relatively light insured losses of around $US200-$US400 million ($189-$378 million) as it hit North Carolina, according to catastrophe modeller Eqecat.

This comes in addition to the $US500-$US1.1 billion ($472-$1 billion) of insured losses, mainly sustained in the Bahamas, estimated by fellow modeller AIR Worldwide when Irene tracked across the eastern Caribbean.

Equity markets had factored in an insured loss of around $US10 billion ($9.44 billion), with losses in excess of that figure generally agreed to be required to tip the market.

Irene crossed the coast near Cape Lookout in North Carolina on Saturday morning around 7.30am US eastern daylight time as a category one hurricane with maximum winds estimated at 140kmh after weakening from its earlier category three status.

It has since been downgraded to tropical storm status and tracked along the US east coast through New Jersey, New York City and Long Island, and towards Boston and New England.

Ahead of its New York landfall, Eqecat said it is “very likely that a landfall of Tropical Storm Irene in New York will result in larger damages and losses than those seen in North Carolina”.

Due to the size and breadth of the weather system, Irene is presenting a significant flood risk, which will come as a major blow to the country’s already cash-strapped National Flood Insurance Program.

Significant flooding has reportedly already occurred along the Jersey Shore, Long Island and in downtown Manhattan, with reports of flooding in the Holland Tunnel and the Hudson and East rivers overspilling.

But “the worst-case scenario of a lower Manhattan under water and flooded subways has been averted”, AIR Worldwide says.

Airlines were grounded, the bustling gambling centre of Atlantic City was a ghost town, train networks – including New York’s subway – suspended and mass evacuations ordered ahead of the hurricane, and in an area populated by more than 65 million people, analysts say business interruption and additional living expenses claims may be significant.

The National Hurricane Centre has now begun issuing warnings for Tropical Storm Jose, with a storm warning currently in effect in Bermuda. But Jose is expected to weaken rather than strengthen as it edges towards land.