Wet start to January boosts Pacific Northwest snowpack, water supply forecast

A wet start to January has boosted snowpack levels as well as hydro supply forecasts across the Pacific Northwest after a dry start to the water year.

The water supply forecast year, which runs Oct. 1-Sept. 30, started off warmer-than-normal and in December there was less precipitation than normal, but things quickly turned around at the start of the new calendar year.

"The start of January has been quite wet across our domain," hydrometeorologist Ryan Lucas said during the Jan. 6 Northwest River Forecast Center water supply briefing, adding snowpack did not look good in December but has improved in recent weeks. "It's a pleasant way to start the water year. Certainty better than where we were at this point last year."

For the most part, the snowpack is currently near to above-normal, Lucas said. Water supply projections for most locations in the footprint are near to above normal for the forecast period.

The Dalles water supply forecast is currently at 104% of normal for the April-September forecast period, 9 points higher than a year ago, after trending below year-ago levels in October and November, according to Northwest River Forecast Center data.

Inflows at The Dalles have averaged 124.8 kcfs since Oct. 1, 5% above the same period a year ago, according to US Army Corps of Engineers data. So far in January, inflows at The Dalles averaged 179.5 kcfs, 17.4% above the three-year January average and 9% above December's average.

The Dalles Dam serves as the barometer for hydro conditions in the region. Less hydro generation in the Pacific Northwest translates to less generation available for exports to neighboring regions.

Seasonal outlook

The Climate Prediction Center's three-month outlook indicates a greater probability for below-normal temperatures and above-normal precipitation across most of the Pacific Northwest.

"The majority of models indicate La Niña is expected to continue through winter 2021-22 and into spring 2022," according to the CPC.

La Niña typically means more precipitation, and more hydro, in the Pacific Northwest. However, La Niña's expectations did not ring true in 2021 when record drought, high temperatures, and wildfires swept the West and drove the California power grid to the edge.

"We are expecting La Niña conditions," Lucas said of the current forecast, but added, "a lot can happen between now and the end of the water year."

Hydro facility reopens

The California Department of Water Resources said Jan. 4 that it resumed operations at its Hyatt Powerplant, about five months after the plant was shut down because of low water levels caused by severe drought conditions.

The 750-MW Hyatt Powerplant near Lake Oroville was taken offline Aug. 5 for the first time in history.

For now, the plant is operating on a limited basis, the department said, with one generating unit out of six producing power. The department expects an average outflow of 900 cubic feet per second, which is expected to produce about 30 MW. Outflows will initially remain low because of reduced agricultural demands and improved delta salinity conditions, the department said, adding that other units will be brought online as demand for electricity increases and lake levels rise.

The plant, on average, produces around 100-400 MW of power generation, according to the DWR.

Power forwards

Despite slipping recently, summer power forwards are trending higher than 2021 packages at the same time last year.

Mid-C on-peak July is currently in the upper $60s/MWh, 54% above its 2021 counterpart. The 2022 package has fallen from a peak of $102.30/MWh Sept. 15, according to S&P Global Platts data.

Likewise, on-peak August is in the low $120s/MWh, 85% above the 2021 package. The 2022 package has fallen from a peak of $134.60/MWh reached Nov. 24.