Is Montana heading into drought?

Ask the question, “Is Montana currently experiencing a drought?” and the answer depends almost entirely upon what part of the state you’re talking about.

In the northwest corner of the state, rivers like the Kootenai and the Yaak are at historic lows, and reservoir levels near Deer Lodge and Philipsburg have dropped to half their seasonal averages.

Travel east and water supply conditions are significantly better. From the Three Forks of the Missouri River to Judith Basin, and the Canadian border to the Wyoming line, reservoirs are at or above average August storage levels, and winter wheat and barley production are expected to exceed last year’s totals.

However, the real question isn’t what to make of the crop and water years that are coming to an end, but what can be expected in 2016. And there are some troubling indications that Montana could be facing warmer and drier conditions well into the year ahead.

“They’re talking about a 90 percent chance that we’ll see less snowpack and that temperatures will be warmer than usual,” said Jesse Aber, a water resources specialist with the Montana Department of Natural Resources and Conservation. “They’re also saying this event could extend out into 2016 and 2017 – but you just don’t know.”

What’s causing concern among water resource managers across the West is the presence of the strongest El Nino event since oceanographers began keeping records in the 1950s.

El Nino is the warm phase of a cyclical pattern of warming and cooling that takes place on the surface water of the Pacific Ocean west of Peru. The cycle is important to North America because El Nino impacts the continent’s weather patterns, most commonly during the winter.

“Although each El Nino is different, there are some general patterns that are predictable,” states a recent winter weather outlook for the Missouri River Basin published by NOAA, the National Oceanic and Atmospheric Administration. “This pattern brings above-normal temperatures to much of the Missouri River Basin region, particularly across the northern tier of the basin. Snowpack in the northern Rockies and plains can be reduced and heavy snow events may be milder and less frequent.”

And it is snowpack — or a lack of it — that precipitated a large part of the extreme drought conditions currently occurring in the northwest corner of Montana.

Looking back at the 2014-2015 water year, which begins and ends on Oct. 1 of each calendar year, nearly all of Montana received near normal precipitation — including counties in the state’s drought-stricken northwest corner. Problems with the area’s water supply were triggered by winter temperatures that were four to 10 degrees above normal.

“It was warm enough that we were seeing rain fall in our mountain elevations early on instead of snow,” said Gina Loss with the National Weather Service. “Then there was an early melt-out that was two, three and maybe four weeks ahead of average in some locations.”

By April most of the lower elevation snowpack had already melted away. One month later, environmental scientists measuring snowpacks in Glacier National Park were hiking high alpine trails usually impassible with snow well into June.

“That first snowfall and the last to melt out — that’s really a critical component to keeping streams fed,” Loss said. “The mountain snow is our bank of water to get us through most of the summer. We lost that bank account in May and June. We had nothing to carry us through July and August, and that’s part of why you’re seeing those record low stream flows right now.”

The early melt-off did fill downstream reservoirs early in the year, and if the spring rains had arrived in May and June as expected, water levels would have been near normal. But they didn’t.

“That northwest corner actually did OK for precipitation early on in the water year,” Loss said. “It’s just that late in the winter the tap shut off.”

According to NOAA statistics, from April through August, some areas in northwest Montana received less than 20-percent of their average precipitation for that period. The absence of normal spring rains sealed the deal on drought for the region.

East of the Divide things were different.

While the whole state experienced a warmer-than-average winter, heavy spring rains in the Wind River Range of Wyoming sent the Big Horn, Tongue and Powder rivers of southeast Montana into flood stage early on, and strategically timed rains in May and July took the edge off for dry land farmers across much of the eastern two-thirds of the state.

Perhaps more significantly, grain growers from the Fairfield Bench east across the Hi-Line benefited in 2015 from a disastrous rain event that struck a year earlier.

On Aug. 21, 2014, a three-day storm drenched most of the northern tier of eastern Montana, dropping as much as 10 inches of precipitation in some locations. Coming right in the midst of harvest, the deluge caused record damage to a large portion of the state’s spring wheat and barley crops, but it also set up excellent soil moisture conditions heading into the winter.

A surplus of subsoil moisture helped many winter wheat and barley producers bring in a good crop this year, even though crop year precipitation totals (which runs from April 1 to July 31) were less than ideal.

“That was one of our saving graces,” Loss said of the August 2014 rains. “With some autumn precipitation, we came in with good soil moisture. That bought us a little bit of time. Had we not had that, we would have been in worse shape yet.”

“A lot of places in the Musselshell Basin are average or better than average,” said Wayne Berkus, section chief for the DNRC. “That shows you what kind of (moisture) was available to keep forage, crops and fisheries in a somewhat near average status.”

But now that surplus of moisture held behind dams and deep in the soil profile is being exhausted, leaving many water managers nervous about prospects for the year ahead.

On Aug. 5, researchers from the National Weather Service’s Climate Prediction Center working at a benchmark location in the east Pacific Ocean recorded surface water temperatures 3.4 degrees Fahrenheit above average — slightly higher than during the record breaking El Nino event of 1997-1998.

In the winter of 1997-1998, precipitation was near average across Montana, but it was also the second warmest in the state’s history. If the winter of 2015- 2016 follows the typical strong El Nino pattern, it will set the state up for a second consecutive year of poor late-season snowpacks piled on top of what has already been a drier-than-average late spring and summer.

Loss emphasizes that predicating seasonal weather patterns is notoriously difficult, and that many contributing factors could mitigate or even reverse the El Nino effects. But historical data offer good insight on what to expect.

“We have gone back and looked as six different strong El Nino events,” she said. “Those were in 1957, 1965, 1972, 1982, 1991 and 1997. In all of those events precipitation in western Montana came up short. Some years were very significant, some years were more minor, but they all came up short of precipitation.”

“East of the Divide the trend is not quite as clear,” Loss said. “Some years were near normal, some years were below normal. None of the years came in with above-normal precipitation. If we look at a composite of all of those years, we are looking at pretty dry conditions west of the Divide and some dry conditions in central and southwest Montana.

“If they’re going in to winter with already low reservoirs this year, and we’re expecting lower-than-average precipitation, it could be a big concern next year.”

“If I was anybody trying to fill a reservoir for next year, I would be pretty stingy with the water,” Berkus added.

At the August meeting of the Governor’s Drought Advisory Committee, the DNRC characterized 13 of Montana’s 56 counties as being in “severe drought.” The driest conditions are concentrated in the state’s northwest corner, but spill east across the Continental Divide into Glacier, Pondera and Teton counties, and south toward the Beaverhead and Madison county areas.

Following the Aug. 20 meeting, Gov. Steve Bullock asked for a federal disaster designation for Lake County, noting that up to 70 percent of the county’s forage and hay crops were a loss and some ranchers were being forced to sell off their herds.

And while streams in many parts of eastern Montana are at near-normal water levels, flows on the northern part of the front range, including Cut Bank Creek, the Two Medicine River, Badger Creek and the Marias River, are all untypically low.

“I would definitely plan for it,” Loss said of expectations for a warm, dry year ahead. “Especially considering that we’re going into this coming off an already dry season. Irrigation takes some of that volatility out, but especially for those people that are on water systems of some kind, that first year doesn’t hit quite as hard as the second year and then the following year after that hits a little harder yet.”

“Conservation of water is definitely something to be considered, even early on in a drought,” she added. “Don’t wait until you think your well is going dry.

“I just think it’s something that people need to be aware is going on,” she said.