US faces rising heatwave and hurricane threats

The US faces one of its "more active hurricane seasons on record", and a growing likelihood of a La Nina weather pattern, which often spells a crop-damaging heatwave, official forecasts have warned.

The Atlantic hurricane season, which typically peaks in August, could produce up to 23 named storms and seven major hurricanes – compared with an average of two – America's National Oceanic and Atmospheric Administration (NOAA) said.

That would put this season nor far behind 2005's, the most active so far, which witnessed 28 major storms, of which seven developing into major hurricanes, and caused an estimated US$130 billion of damages.

The NOAA also warned of a growing risk of La Nina, a weather pattern linked to Pacific conditions which often cause hot and dry weather in America's main crop growing regions, besides being an indicator of a greater hurricane risk.

"Conditions in the equatorial Pacific Ocean are becoming increasingly favourable for La Nina," the administration said.

Elwynn Taylor, a climatologist at Iowa State University, said that a La Nina had a 25% of developing before the end of next month.

"The sea temperature is cooling from Tahiti east, a La Nina indicator, and the atmospheric pressure is highest in a month at Tahiti, another indicator," Professor Taylor said.

Meanwhile, soy futures advanced on speculation that the US government will report higher demand from crushers and that La Nina weather conditions may hurt the crop.

La Nina may cause dry weather in late summer, hurting the US soy crop, said analysts. There is a "growing possibility" of La Nina developing during the second half of 2010, the US Climate Prediction Center said.