A little more than one month out from the official end to the 2012 hurricane season and risk modellers are calling it one of the most active seasons in more than 150 years.Through October 17, the 2012 Atlantic Hurricane Season has produced 17 named storms, nine hurricanes and one major hurricane (category three Michael). Hurricane Isaac (category one hurricane in Louisiana) was the only hurricane to make landfall on the US mainland causing in excess of $1 billion in insured losses and significant disruption. Tropical storms Beryl and Debby also made landfall in northern Florida.According to Risk Management Solutions (RMS), this year’s hurricane season is the second most prevalent for storm activity since records were initially recorded in 1851. While many of these events did not make landfall, a considerable number formed and were officially named. As of September 13, there were more named storms this year than any other with the exception of 2005 and 2011.“Seasonal forecasts for 2012, issued at the beginning of August called for around 14 tropical storms in the Atlantic in 2012,” said Christine Ziehmann, RMS’ director of product management. “The 2012 season is currently on track to exceed these forecasts, especially if September is typical of the 1995-2011 average.”According to modelling firm Eqecat, activity in the Atlantic has been significantly higher than the historic seasonal average of 6.5 hurricanes.“Early season forecasts from the US National Hurricane Center, Colorado State and others predicted a below average level of seasonal activity, but a growing La Niña condition in the Northern Pacific Ocean led to a higher than average level of observed activity to date,” said Tom Larsen, SVP, product architect at Eqecat.But heading into the rest of October and the final month of the season, the forecast is looking quieter than normal.“October is historically a very active month for tropical storm development but current forecast models are predicting a below average remainder of the season,” said Mr Larsen. “The developing La Niña conditions that influenced the activity in the early summer are now transitioning to an EL Niño condition which is disruptive to North Atlantic tropical storm formation and strengthening.”While previous years have resulted in more property insurance claims, so far this year, only one hurricane has made landfall in the US — Hurricane Isaac.Boston-based modelling firm AIR Worldwide states that while the frequency of hurricanes has increased, that doesn’t mean an increase for landfall potential.“While there is a clear correlation between warmer-than-average sea surface temperatures (SSTs) and hurricane activity in the Atlantic basin, the relationship between activity in the Atlantic basin and hurricane landfall activity is highly uncertain,” said Dr Jayanta Guin, senior vice president of research and modelling at AIR Worldwide.“This year, for example, has been a very active season, but there has been just one US hurricane landfall: Isaac. In fact, the data shows that landfall frequency does not scale in proportion to basin activity. If we assumed so, this could lead to an overestimation of risk. Indeed there is some recent research that suggests that as SSTs warm, storms may form further east in the Atlantic and curve north before reaching the US coast.”According to AIR, research has shown that basinwide activity is not always a reliable indicator of losses. The company said that through 2011, six seasons since 1995 have experienced above-average hurricane activity in the basin but with zero or just one US landfall.“Given that the long-term average annual number of US landfalls is about two, there have only been five seasons in the last 15 years with above average landfall activity,” said Dr Guin. “Additionally, since the current period of warm SSTs began in 1995, there have been 32 loss-causing hurricane landfalls in the US, which is what one would expect if you look at the entire period beginning in 1900.”