Herald and News: Basin winters warmer, rainier

Basin winters warmer, rainier

Precipitation has been declining each year from November to March

By STEVE KADEL

H&N Staff Writer

February 1, 2007

If it feels like Klamath Basin winters are warmer than they were decades ago, you’re not imagining things.

A Bureau of Reclamation official says that’s been the trend for the past century.

Thomas Perry, a hydrologist from Reclamation’s Technical Service Center in Denver, presented his data this week during a meeting of the National Research Council’s Committee on Hydrology, Ecology and Fishes of the Klamath Basin.

The event at Shilo Inn brought together top researchers from Oregon and other Western states.

Perry’s information shows that precipitation in the Klamath Basin has steadily been declining each year from November through March. Warmer temperatures through the decades have brought more winter rain and less snow, Perry said without giving specific numbers.

Water storage needed

Because mountain snowmelt has occurred earlier during the past 50 years, spring streamflows now arrive one or more weeks earlier than before, Perry said.

The changing precipitation pattern with less snow runoff into Upper Klamath Lake has implications for Klamath Basin irrigators, said Jon Hicks, chief of planning division for Reclamation’s Klamath Falls office.

“It really foretells the need for extra water storage projects like Long Lake with deep cold water and minimal evaporation,” he said.

Nationwide trend

Hicks said warmer winter weather has been a trend across the nation, particularly in the Sierras of California.

“It can cause some flooding in the early runoff, and shortages of water in the summer when we no longer have runoff,” he said.

Anecdotal evidence supports the view of climate change in the Klamath Basin.

“In the 1930s and ‘40s a Model T could be driven across Upper Klamath Lake in the winter,” Perry said. “If you tried that today you’d probably fall through the ice.”

Higher freezing level

He called the temperature increase from 1895 until now “striking.” The average wintertime freezing level has risen about 1,000 feet in the past 100 years. Perry noted the only recorded time Crater Lake froze was from February to May in 1949.

The seasonal decline in snowpack is seen across the Klamath Basin watershed, although it is more pronounced at lower elevations. However, there’s nothing to indicate the same trend won’t occur at higher and higher elevations over coming decades, Perry said.