Environment

When will the rivers rise? In Idaho, experts watch closely

Collecting snowpack data at Mores Creek

Ron Abramovich, a hydrologist with Natural Resources Conservation Service snow survey, and a crew take measurements at Bad Bear campground and Mores Creek Summit north of Idaho City. Measuring snow depth and snow weight, they calculate the amount
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Ron Abramovich, a hydrologist with Natural Resources Conservation Service snow survey, and a crew take measurements at Bad Bear campground and Mores Creek Summit north of Idaho City. Measuring snow depth and snow weight, they calculate the amount

Ron Abramovich says he knew Southern Idaho was going to have a good snow season as early as last year.

The water supply specialist for the USDA Natural Resources Conservation Service has been measuring snow depths and water content in Idaho since 1991. He’s seen the drought years and the flood years, and the climate patterns that preceded them.

One of the strongest El Niño patterns in decades occurred in 2015 and 2016, when southern Pacific Ocean temperatures warmed as a part of the El Niño-Southern Oscillation, or ENSO climate pattern. ENSO is a naturally occurring phenomenon that involves fluctuating ocean temperatures in the Pacific.

“Every time we had a strong El Niño, the following year was typically wetter than normal,” Abramovich said.

The snowpack in the higher elevations of the Boise River watershed are about 115 percent of the 30-year average, after the watershed got 163 percent of the average during January, according to the latest Idaho Water Supply Outlook. Overall, Southern Idaho snowpacks are well above average for Feb. 1, prompting a sigh of relief from farmers, whitewater outfitters, Idaho Power and others who depend on good flows for their livelihoods.

But the record snowfall that covered the lower elevations, including most of the Treasure Valley, brought with it overloaded roofs that caused dozens of farms to lose entire crops of stored onions. Stores, schools and farmers in Weiser and elsewhere lost roofs under tons of wet snow, and runoff threatened flood damage along the Snake River in Payette County.

In the low-elevation Weiser watershed, snow-measuring sites the Natural Resources Conservation Service measures at 4,000 to 4,500 feet ranged between 300 percent and 500 percent of the median, presenting threat of flood anytime from now to spring, depending on how that snow melts, Abramovich said.

But above 5,000 feet in the same drainage, the snowpack is below average — at 75 percent to 95 percent — reducing the threat of a catastrophic rain-on-snow sequence that can quickly swell streams and force people from their homes.

WATCHING THE WEATHER

Abramovich, 54, has developed an instinct to aid the data he collects every winter by trudging through snowy Idaho mountains on snowshoes. The network maintains 118 snow courses, stretching from the Selkirk Mountains north of Spokane to Jarbidge, Nev., on the south.

“You have to live through those drought and flood years to know what happened and what will happen again,” Abramovich said.

The data itself goes back to the establishment of the Soil Conservation Service in the 1930s. The specific snow courses measured monthly from Jan. 1 to April 1 were established by Morley Nelson, the conservation pioneer who had Abramovich’s job from the 1940s until his retirement in 1970.

Today, 78 of the snow courses are automated digital Snotel sites that provide data on a daily and even hourly basis. But the rest depend on manual measurement, done in the same places and with the same protocols to ensure validity.

Abramovich also depends on his networks of contacts throughout the small towns and urban communities of Idaho to report their experiences and measurements.

“I keep my ears open,” he said.

Rex Barrie, of Star, the watermaster for Idaho’s Water District 63, is responsible for administering delivery of water to farmers who irrigate 320,000 acres. Water goes to city water departments throughout the valley and to Suez, the private company that serves Boise homes.

“Ron’s institutional memory and his insights are invaluable to my water users,” Barrie said.

‘CURVEBALLS FROM MOTHER NATURE’

In 1998, the University of Idaho published “Climates of Idaho,” which Abramovich co-wrote and compiled. It showed that from the 1950s through the late 1970s, snowpacks and streams’ flows were fairly stable and predictable.

Since then, scientists have seen sometimes extreme swings from wet to dry. This climate variability has made predicting more difficult.

The evidence that the runoff timing has changed is based on flow gauges maintained by the U.S. Geological Survey. One of the oldest is the gauge on the Middle Fork of the Boise River, installed near Twin Springs above Arrowrock Dam in 1912.

It shows that runoff that used to begin in early April now starts in late March. That flow used to peak in late May or June; now it peaks in early May.

The past 30 years generally have been drier. With Idaho snowpack melting and peaking earlier, flows are even lower in the late summer and fall in the tributaries above reservoirs and in rivers without dams.

“In the spring we’ve seen in the last couple of years, sometimes that moisture shuts off midwinter and we get wet again in the springtime,” Abramovich said. “Those curveballs from Mother Nature are hard to predict.”

For Barrie’s farmers, the climate variability has real financial costs. Right now farmers are deciding what crops to plant this spring, based in part on how much water they expect to be available this summer.

The Boise and Payette river reservoirs are likely to fill this year, so the issue for those basins is when will flows drop to the point when the water supply no longer comes primarily from natural flows, but from reservoir storage.

If farmers pick high-value crops like corn, beets or potatoes, and the natural flows drops early, they might not be able to finish their crop in the late summer, especially if the weather turns particularly hot and dry.

‘CLIMATE VARIABILITY’

This climate variability — it’s the term people use because of the skepticism about human-caused climate change among many farmers and Idaho lawmakers — affects things besides farmers’ irrigation water. It affects fish, for instance, especially since stream temperatures are getting warmer.

Varying conditions also affect recreation, beyond the obvious connection between snowfall and ski resort operations. Last year, for example, high early-summer flows kept floaters and tubers off the Boise River through Boise until later in the float season. On rivers such as the Middle Fork of the Salmon, low flows late in the season limit the number of whitewater rafting days on which outfitters and river runners depend.

That won’t happen this year, since heavy snows in the upper reaches of the Salmon River Basin have the snowpack at about normal. But in North Idaho and adjacent watersheds like the Clearwater and St. Joe, the snowpack today is below normal.

“In January, the Salmon River was the dividing track for the jet stream and storm systems that brought well below-normal precipitation to the north and up to twice normal January amounts south of the river,” Abramovich said.

A LIFE OF SNOW

Snow has always been a part of Abramovich’s life. He grew in Ohio and went to Colorado State University before going to work for the U.S. Geological Survey in southwest Colorado. He worked at a ski shop in Telluride, Colo., where he met his wife, Janice, who coached the ski team. They have two grown children.

Abramovich said his instincts tell him the Treasure Valley and most of Southern Idaho should have a good water year.

In the Boise River Basin, the total water content of the snow sitting in the mountains is about 70 percent of the normal for April 1 — and the basin has two months left to go.

“We’re off to a great start,” he said. “We just don’t want to quit midwinter.”

Rocky Barker: 208-377-6484, @RockyBarker

Gauging our water

Some measures of where Idaho stands:

▪  Bogus Basin ski area: 71 inches of base depth on Feb. 1 (compared to 14 to 58 inches the past five years)

▪  Boise watershed snowpack: 115 percent of the 30-year average, after a January with 163 percent of average

▪  Bear River and Owyhee basins: 170 percent of the 30-year average

▪  Spokane River Basin: 61 percent of the 30-year average

▪  Salmon River Basin 103 percent of the 30-year average

▪  Payette River Basin: 97 percent of the 30-year average

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