By Marcy Stamper
Although mountain snowpack is well above normal in the North Cascades — and almost everywhere across the state — the region’s water supply specialist nevertheless described March precipitation as “disappointing, to say the least.”
The entire state, except the Olympics, received precipitation far below normal for March, meaning that there was little moisture to add to the mountain snowpack, which is key for agriculture, rivers and fish through the summer and fall, Water Supply Specialist Scott Pattee with the Natural Resources Conservation Service said in the April Water Supply Report.
But in the last week of March, several large storms hit the mountains, bolstering an already impressive snowpack, he added. Snowpack refers to snow-water content (or equivalent), which is what counts when it comes to spring runoff.
March precipitation in the Upper Columbia basin tied for the lowest in the state at just 35% of normal, although the entire water year for the basin was at 105% of average. March weather east of the Cascade crest was a bit warmer than usual, but it was cooler west of the crest. Mountain temperatures were normal, Pattee said.
The snowpack in the Methow was 118% of normal at the start of April, compared to 106% last year. The Okanogan was at 116% of normal, 2 percentage points more than last year. Conconully Lake was much better off than last year, at 110% of normal, compared with 69% last year. Combined storage in the Conconully reservoirs was 73% of normal at the beginning of April.
While it’s still early — and a few degrees of temperature in either direction can significantly affect melt-off — current forecasts for streamflows from April through September for the Upper Columbia are 96% to 130% of average, Pattee said. The Methow River at Pateros was running at 99% of average for April. Current streamflows are lower for the Okanogan River (86%) and the Similkameen River (86%).
The U.S. Drought Monitor forecast for the eastern two-thirds of Okanogan County is “abnormally dry,” the least severe on the drought-intensity scale, which runs from “abnormally dry” to “exceptional drought.” That outlook is better than the predictions made back in January, when the drought monitor was forecasting even drier conditions, expecting moderate drought in the south-central parts of the county.