BOISE, Idaho (AP) -- An Idaho snowpack that started the year well above average hit a three-month dry patch that left every basin in the state below the 30-year average by mid-April.
Most of the central part of the state is in 50 to 90 percent range. Four of the state's 21 basins are in the 90 to 100 percent range, including the Northern Panhandle. The Owyhee in southwest Idaho is the lowest at 34 percent.
"After a great start to the water year, we were in good shape," said Ron Abramovich, a water specialist with the Idaho Natural Resources Conservation Service. "But then the weather changed in early January."
He said central Idaho weather stations set 16 records for least amount of precipitation from January through March, with information going back to the 1980s. Another 24 sites around the state saw second or third lowest totals ever recorded during those three months.
He said the state had the equivalent of an "A'' letter grade at the start of the year, but is now down to a "C."
What happened, he said, was a high pressure ridge built of the coast of Washington state and deflected Pacific storms around Idaho.
"It was like a relief pitcher who came in an struck us out," Abramovich said Friday. "It's happened two years in a row now."
The ramifications of the current snowpack, he said, include farmers in some areas trying to decide whether to plant grains that need less water or corn that needs more water but can be more profitable.
"What we really need now is some more spring rains," he said. "It will be a little bonus for what we have in the mountains."
He said spring rains could put off the start of the irrigation season, saving water for later in the year. Without rains, he said that reservoirs in southern Idaho will likely be at minimum storage levels by summer's end.
This is also the first year of a new 30-year average, which dropped out the wet 1970s and added the dry 2000s.
Abramovich said that if not for that change, the percentages for Idaho's snowpack would be about 8 to 12 percent below what they are listed at now. But he also noted the current 30-year average that spans 1981 to 2010 is more representative of the last 80 years.
One thing that isn't average, Abramovich said, is what he called weather variability.
"We're seeing more the extremes," he said, "which makes it more of a challenge to forecast the streams and be a water manager."