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Columbia Basin's Snowpack Still Running Far Below Normal by Barry Espenson Columbia Basin Bulletin - January 10, 2003

A stormy late-December and early January helped pull Columbia River Basin snowpack totals up, but much work remains if Mother Nature is to bank the amount of moisture needed to satisfy the desires of hydro generators, agricultural interests and fish managers.

After a dry summer and early fall, the basin endured a dusty (relatively speaking) start to its water year. October-November precipitation was 51 percent of normal on the Columbia above Grand Coulee Dam and at the Snake River above Ice Harbor Dam. Precipitation in the basin above The Dalles Dam was only 49 percent of the average for the period 1971-2000, according to the National Weather Service's Northwest River Forecast Center.

Hal Anderson of Idaho's Department of Water Resources called the state's snowpack accumulation through early December "abysmal."

One month ago (Dec. 8), National Resources Conservation Service snow reports indicated that the region was on a drier course than even the winter of 2000-2001. That winter's snowpack produced the second lowest runoff total on record -- 52.8 million acre feet runoff or 55 percent of average.

On Dec. 8, early-season snowpack totals ranged from 65 percent of average water content for streams draining into the Snake River above Palisades in southeast Idaho, to a mere 12 percent of average for that date in Washington's Yakima River basin. Most of the Columbia Basin's drainages hovered in the 40-60 percent of average range for that date. In most cases the start to the water year (Oct. 1) was worse than 2000-2001.

But those readings were early in the wet season. Traditionally the region gets about 60 percent of its snowpack accumulation after the New Year. And a series of storms at year's end served to bring the water situation closer to normal. Hopes for an "average" year, however, still depend on greater than normal precipitation through January, February and March.

December precipitation was: 93 percent of normal (1971-2000) at Columbia above Coulee, 101 percent of normal at the Snake River above Ice Harbor, and 102 percent at Columbia above The Dalles, according to the NWRFC.

That near-normal month lifted seasonal (October through December) precipitation averages to 67 percent of normal(1971-2000) at Columbia above Coulee, 71 percent of normal at the Snake River above Ice Harbor, and 70 percent at Columbia above the Dalles.

The January "final" water supply forecast issued Thursday for the January through July period predicts total runoff as measured at The Dalles at 80.5 million acre feet. That forecast -- 75 percent of normal -- is made with the assumption that the region will receive its normal precipitation during that time.

"To get back to normal (runoff) we'd need to get something between 125 and 130 percent of normal" precipitation, said Tom Fero, NWRCS senior hydrologist. "I don't expect that kind of precipitation.

As of Wednesday (Jan. 8), snowpack totals had inched up somewhat. Yakima's, for example, jumped from 12 percent to 79 percent of normal from Dec. 8 to Jan. 8. The Snake above Palisades registered 74 percent of normal, up nine percentage points in a month.

"Really, this last wet period was very beneficial to us," Anderson said of a series of storms coming off the Pacific Ocean from mid-December through the first few days of January. Idaho has, generally, suffered through two consecutive years of below average precipitation while Oregon and Washington got, for the most part, a reprieve last year after the 2000-2001 drought. Montana is amidst a prolonged drought.

"Now we have several areas of the state that have actually gone above average," Anderson said. The Big and Little Wood basins stood at 111 percent of average and the Big and Little Lost basins stood at 100 percent of average snowpack through Tuesday. The Weiser, Payette, Boise river snowpack was 96 percent of average and the Owyhee, Malheur 84 percent. All had grown by from 40 to 50 percent over the past month, as a percent of average for a particular date.

The NRCS, which monitors snowpacks across the country and region, reported that the overall snowpack index at The Dalles Dam was 71 percent of average for Jan. 1 compared to 102 percent last year and only 59 percent in 2001. The Dalles index accounts for runoff from tributaries from a vast part of the basin in both the United States and Canada, leaving out only lower river tributaries. The composite snowpack is 31 percent of a normal year's peak, compared to 45 percent last year and 26 percent in 2001.

The snowpack that would feed the Henrys Fork, Teton, Willow, Blackfoot and Portneuf rivers in Idaho-- as well as vast tracks of irrigated farmland -- improved by 22 percent over the past month but was still well below average at 74 percent of average on Jan. 8.

"The real concern is that we still have a fair amount to go" to accumulate "average" snowpack, Anderson said. He said that most Idaho drainages would need 110 to 120 percent of average accumulation over the next three months before it could expect an average runoff. Back-to-back dry years have sapped soils in many parts of the region, which means the thirsty earth will absorb more of the runoff than in a normal year and leave less for downstream uses.

The phenomenon "El Nino," tends to tip the weather scales in favor of a drier, warmer winter across much of the Northwest, with the main storm tracks shunted to the north and south. That means less rain and snow.

"It never is textbook but this is probably as close as you could get to textbook," the Bonneville Power Administration's Nancy Stephan said of the reigning El Nino. Even during the recent wet period, the center of the storms missed the basin's bull's eye.

But, while the precipitation totals this year through the first three months of the water year virtually match those of the drought year -- 67 percent of average on Jan. 1 2001 as opposed to 66 percent this year -- the precipitation came in a better pattern to build snowpack. In 2000, most of the precipitation came October and early November as rain across the region. This year it came in a rush at the very end of the year and much of it stuck as snow in higher elevations.

"The snowpack is considerably better" than two years ago," Stephan said. It is better, but not good.

Recent weather patterns, and long term forecasts, would indicate that the region will be influenced by El Nino for the balance of the winter. Making up the snowpack deficit will be a long shot.

"Is it out of the question?" Fero asked rhetorically. "No, but I think it is very unlikely."

The Canadian snowpack above Arrow Lakes was reported as 65 percent of average on Jan. 1, according to the NRCS. The area above Mica and Arrow Lakes in Canada normally provides about 26 percent of the Columbia Basin's total runoff -- by far the biggest contributor.

"The only other one that even comes close is the Kootenai" at 17 percent, said Tom Perkins of the NRCS. The bulk of the Kootenai's runoff also comes from Canadian snowpack.

The Pend Oreille system is reported as 68 percent of average, with the Flathead, Bitterroot, and Clark Fork snow conditions being among the worst in the Columbia, according to the NRCS.

(For more on Montana snowpack, see Story No. 8 below)

The Snake above Lower Granite has the best snow in the basin, at 82 percent of average as of Jan. 1.

Most of the other snowpacks across the region improved over the past month, but stayed well below normal. The Clearwater and Salmon (77 percent of average for the date), the Idaho panhandle drainages (71 percent), Upper (62 percent) and Lower (61 percent) Clark ForK River basins, the Bitterroot (68 percent), Kootenai in Montana (79 percent), and Flathead (62 percent) had below normal snowpack as of Jan. 8.

The Columbia above the Methow River in Washington had 92 percent of the snowpack in sees on average on Jan. 8. The Chelan, Entiat, and Wentatchee basin snowpack stood at 81 percent of average for the date and the Yakima, Ahtanum was at 79 percent.

The snowpack above the Grande Ronde, Powder and Burnt, and Imnaha rivers -- which feed into the lower Snake River -- had 76 percent of average snowpack. The Umatilla, Walla Walla, Willow drainages had 62 percent and the Deschutes, Crooked, John Day had 81 percent.

The Willamette River in western Oregon had a mere 52 percent of average snowpack for Jan. 8 while the Lewis and Cowlitz drainages in southwest Washington had 68 percent.

The recent surge was welcomed but may not be enough to help head off an increase in the wholesale power rates that the Bonneville Power Administration bills its customers. At the end of November, the head of the financially challenged federal marketing agency said conditions were nearly ripe to initiate the process necessary to raise rates via a safety net cost recovery adjustment clause in the contracts.

BPA CEO Steve Wright said at the time that strong sales of surplus power were needed to help right the financial ship, and avoid or reduce the need for rate increases. Much of the power sold is generated in the federal Columbia River basin hydrosystem.

"We said two things -- we need a lot of surplus energy sales and we need a lot of water," said BPA spokesman Bill Murlin. Neither one has really materialized. And eyes were blinking at the sun again this week as a high pressure ridge set up, drying out much of the region and eliminating potential snowpack building days.

"The weather's been mild," across the West, Murlin said. "Normally we have a nastier winter so we have less demand (this year) in our region." So while prices are slightly better (a spot price of $39 per megawatt hour this week as compared to prices that slumped under $20 last summer), the demand for any surplus power is relatively low because of the weather and an ailing economy.

The agency must also consider that a certain portion of the year's runoff will be dedicated to fish operations intended to improve survival of fish listed under the Endangered Species Act, as well as unlisted stocks such as the Hanford Reach fall chinook.

"We have to make sure the reservoirs have enough water" to provide flows for migrating salmon and steelhead next spring and summer, and to keep salmon nests covered this winter as well. Ongoing operations include protection for ESA-listed chum redds below Bonneville Dam and for fall chinook per the Vernita Bar Agreement.

"Now is the time that we'd like to be generating surplus energy and selling surplus energy," Murlin said. A decision will likely be made later this month whether to initiate the rate increase process, he said.

The system has a total average generating capability of 8,343 in average megawatts. During this past December the system operated, on average, at 75 percent of that capacity. Murlin stressed that that average represented a broad range of generating scenarios. But the limited amount of fuel (water) and demand for energy limited BPA's power, and revenue, generating potential.

Related Pages:
NRCS: www.wcc.nrcs.usda.gov
NWRFC: www.nwrfc.noaa.gov
BPA: www.bpa.gov/indexmain.shtml