Menge said in a statement that the Department of Natural Resources opened the east and west coastal areas of state-owned lands on the North Slope to oil and gas exploration activity yesterday based on measurement standards developed in a scientific study completed in 2004 by the department’s Division of Mining, Land and Water.

“The division conducted its study in response to the winter oil exploration seasons becoming shorter because of warming weather and changes in measuring techniques,” Menge said. “While the winter exploration season had been effectively cut in half since the early 1970s, this winter’s opening is the earliest since 1995, thanks to good science and cooperative weather.”

The commissioner said new snow depth and soil temperature standards developed through the study allow the department to lengthen the oil and gas exploration winter season without increasing the impact on the tundra. The study found that snowfall is more important in protecting the tundra than previously understood while ground hardness, previously the determining factor in opening the tundra, is relatively less important after a certain point. The department is now opening the tundra after the accumulation of at least six inches of snow in the coastal area and nine inches of snow in the Foothills area, and after soils reach a temperature of minus-five degrees Celsius.

The department said its monitoring of some of the early exploration activity allowed last year, followed by additional study this summer, showed that the early opening did not result in any increased impact on the tundra.

“We are confident that any seismic activity that occurs under these conditions will not cause any increased impact to the tundra,” said Wyn Menefee, chief of operations for the Division of Mining, Land and Water.

“We will, however, continue to monitor the effect of exploration based on the new standards developed,” Menefee said.