Water Outlook: Storms help snowpack in Yakima Basin, but mountain totals uneven

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YAKIMA HERALD-REPUBLIC – PHIL FEROLITO – February snowstorms that hammered the region may have improved the water supply outlook for the year, but concerns linger over whether it was enough to bring a full supply.

As of Wednesday, snowpack in the upper Yakima Basin was at 82 percent of normal for this time of year, and 99 percent in the lower basin, according to the National Water and Climate Center’s snowpack map.

Snow hit the Valley floor hard, bringing up to 10 inches in Yakima alone on a single day — Feb. 9 — and forcing school and road closures and leading to the cancellation of sporting events throughout the area. In the Lower Valley, the snow and cold killed more than 1,800 dairy cows.

But snowfall wasn’t as even in the mountains, said Chris Lynch, civil engineer with the Bureau of Reclamation.

“It’s funny — this year it seems like that swath of the Snoqualmie Pass area was hit less than other areas,” he said. “We’re tying to make sense of it.”

Just south at Morris Lake in Naches, snowpack is at 97 percent, and even higher, 110 to 112 percent in the watersheds of the Ahtanum, Satus and Toppenish creeks.

“That’s good — that’s solid,” Lynch said. “I think right now, we’re happy with that — the way be bounced back in February. I’m glad we got hit like we did and I’m happy we’re where we’re at.”

A more accurate calculation of water supply will be issued sometime in mid-March, when official assessments of snowpack will be conducted.

The basin’s five reservoirs are now at about 88 percent of what the should be this time of year, Lynch said.

He hopes expected precipitation over the next week or so is enough to reach 100 percent capacity.

“We still have some wetness and cold in the next few weeks,” he said.

Just how mountain snowfall will translate into water supply remains to be seen.

February brought lower-than-normal temperatures, and snowfall was drier than normal as a result, said Scott Pattee with the U.S. Department of Agriculture.

“Water content — that was some of the problem with the snow we got two weeks ago,” he said. “It piled up a few feet of snow in the mountains, but it was dry and didn’t have that water content.”

Pattee said maintenance snowfall is needed in the mountains for the remainder of winter to ensure a strong water supply.

“Essentially, every day that goes by and we don’t get snow, we lose ground,” he said. “Plus we need to add on top of that main snow, especially in the upper Yakima Basin to get that number into a more normal range. Everyone is still keeping an eye on this.”

Another storm bringing a 50 percent chance of snow is expected to hit the Cascade region Friday, according to the National Weather Service.

“It’s a fairly widespread system, so it’s fairly possible that we’ll see some pretty good numbers into the weekend,” said assistant forecaster Ann Adams in Pendleton, Ore.

Posted by : Phil Ferolito, Yakima Herald-Republic, February 20, 2019

Picture: Evan Abell, Yakima Herald-Republic

Snow covers trees near Snoqualmie Pass on Saturday, Feb. 16, 2019 in Snoqualmie Pass, Wash.