GENERAL OUTLOOK
With relatively cool temperatures and a series of storms crossing the Columbia - Snake basin during January, snow continued to accumulate in the main water producing areas. Precipitation was above average in Canada, the Cascades in Oregon and Washington and in most of the Snake River basin. Consequently, most volume forecasts have improved slightly.
January precipitation was greatest in the Columbia River in Canada with 126 percent of average. Southeast Washington and northeast Oregon had the lowest precipitation amounts at 70 percent. The seasonal accumulation of the Columbia River above The Dalles is at 113 percent.
The February 1st snow pack is greatest in the northern areas of the Columbia basin with water equivalents from 120 to 170 percent of average. Near average snowwater equivalents were observed in the upper and middle Snake and in northeast Oregon. The Cascades in southwest Washington and Oregon have well above average snow. Runoff during the month of January was generally slightly above average east of the Cascades, while basins west of the cascades observed above average runoff.
Most volume forecasts increased on February 1st. The greatest increases were in the Upper Columbia, the north Cascades in Washington and on the Upper - Middle Snake basin. The January - July volume for the Columbia River above The Dalles is 119.0 million acre-feet or 112 percent of average. That compares with January - July volume of 104.1 million acre feet in 1998.
A fairly mild and wet January brought moderate rains and major snow to the basin. Mean temperatures departed +5.2 degrees (31 stations) from normal for the Pacific Northwest relative to 1961-1990 normals. Mean temperature departures ranged between 9.0 and -0.3 degrees. January 31st regional snow depths (in inches) follow... 29.9 Tete Jaune BC...37.8 Blue River BC... 65.0 Dixie ID... 11.0 Middle Fork Lodge ID...16.0 Elk City ID... 35.0 West Yellowstone WY... 102.0 Stampede Pass WA...132.0 Stevens Pass WA... 195.0 Ranier Paradise Ranger Station WA... and 122.0 Crator Lake OR.
Record high temperatures were reported at two sites... 60 degrees at Eugene, Oregon on the 10th... 53 degrees at Pocatello, Idaho on the 11th. Daily precipitation records were surpassed at Astoria... 1.62 inches on the 17th... and 0.92 inches on the 29th.
Several minor gulf of Alaska disturbances moved across the basin through the 15th bringing moderate to sometimes heavy rains to coastal areas and heavy snows to the Cascades and eastern portions of the basin... eastern Washington... northern Idaho... western Montana.
A Pacific weather pattern took hold of the region January 15th to the end of the month ushering in numerous storms from the Gulf of Alaska (approximately one every third day)... moderate to heavy
coastal and valley rains on the westside of the Cascades... heavy snow in the Cascades and eastside upper elevations. For January...precipitation was 101 percent of normal (1961-1990) at Columbia above Coulee; 116 percent of normal at the Snake River above Ice Harbor; and 107 percent at Columbia above The Dalles.