Year of weather extremes

WASHINGTON – It’s not just your imagination. America’s weather went wild this year.

It began with a record downpour in the Nevada desert and record warmth in Alaska, and it’s ending with floods in California and wildfires in Texas and Oklahoma that have killed four people and consumed 37,795 acres.

Along the way, at least 214 climate records were smashed or tied, thanks to a slew of hurricanes, 21 straight days of 100-degree-plus temperatures in Fresno, Calif., and wildfires that have burned 8.64 million acres, nearly a quarter-million more than the previous record, set in 2000.

Extremes were everywhere. Above-normal heat covered twice as much land as usual. Excessive rain and/or snow blanketed three times as much land as normal. Average daily low temperatures were warmer than normal across four times as much U.S. territory as in average years.

It was the third-worst year in history for U.S. extreme-weather events, according to the National Climatic Data Center. For 2005’s first 11 months, the nation had an extreme-climate index figure of 35, behind only 1998’s 42 and 1934’s 37. The average annual score is 20.

One form of extreme weather fell short, however: tornadoes. In 2005, there were only half as many killer U.S. tornadoes as recent norms.

The relentless Atlantic hurricane season especially marked 2005 as wild – and tragic.

Many of the remaining extremes came from Alaska, which had 53 percent of the wildfire acreage burned and set temperature, rain and snow records almost weekly. That’s because Alaska is getting hotter from global warming and its permafrost is melting, said Jay Lawrimore, the chief of the National Climatic Data Center’s climate-monitoring branch.

It’s less clear whether what’s happening nationally can be blamed on global warming or results from mere chance. Scientists are researching the question on supercomputers.