Wet December reduces drought, boosts snowpack

Wet December reduces drought, boosts snowpack

Source: Billings Gazette
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BRETT FRENCH french@billingsgazette.com

Heavy snow in December has helped build mountain snowpack and could ease drought that last year plagued 15 Montana counties and nine in Wyoming.

“This winter is shaping up much better than last year,” said Ada Montague, water resource planner for the Montana Department of Natural Resources and Conservation.

A report from DNRC showed that by the end of December, snowpack and the amount of water in the snow were reaching “near normal levels.”

“We’ve had a good December for snowfall,” Montague said, but the weather was so cold that the water content in the snow has been lower than usual.

Northwestern Wyoming is in a league of its own. There, heavy snowfall has blanketed the mountains with snow-reporting sites recording depths more than 250 percent of normal. The Owl Creek recording station, which sits at an elevation of 8,975 feet north of Riverton, Wyo., is reporting snowpack 297 percent of normal.

Snowfall has been so heavy in the region that the Jackson Hole Mountain Resort ski area is reporting 311 inches of snowfall so far this winter, accounting for a 101-inch mountain-top base. Snow has piled up so fast that the backcountry avalanche danger increased to a rating of “high” last week before edging down to “considerable” and “moderate” this week.

Not too much farther north at the headwaters of the Yellowstone River near Cooke City, snow reporting stations are measuring from 136 to 147 percent of normal snowpack. That should bode well for the stream that last year saw an early runoff and by summer was experiencing conditions so warm that a parasite flourished, killing thousands of whitefish along with some trout in the Paradise Valley portion of the river.

In fact, the upper Yellowstone River Basin was tracking the best so far for snowpack at 110 percent of normal. Most of Western Montana along with the St. Mary and Milk river basins were ranging from 70 to 89 percent of normal, the Sun-Teton-Marias area was 94 percent of normal and the Smith-Judith-Musselshell was 67 percent of normal.

Farther south, the snowpack in the Bighorn River Basin in December was 109 percent of average, with runoff into the popular Bighorn River fishery predicted at 127 percent of normal. That means river flows could stay in the sweeter zone for the summer — around 3,000 cfs — with flushing flows in May predicted to top out around 5,500 cfs. Anglers and Montana fishery managers don’t like to see the river drop to 2,500 cfs.

Reservoir levels across Montana were normal to slightly below normal.

Looking farther ahead, the National Weather Service’s Climate Prediction Center calls for western Montana and Wyoming to continue to receive above-normal precipitation for the next month.

“We’re expecting to see our drought conditions improve across most of the state,” Montague said.

Maybe that will help with snowpack in the Little Belt, Deer Lodge, Sapphire, Swan and Lewis ranges, which are reporting levels lower than average.

The drought monitor map showed abnormally dry conditions persisting in portions of western, southwestern and southeastern Montana — the lowest level on the drought monitor scale. Moderate drought continues to persist in portions of western Montana and the southeastern corner.

In Wyoming, severe drought persists on the east-central side of the state, with less intense abnormally dry and moderately dry conditions in portions of the northeast and southeast corners of the state. Like Montana, the amount of Wyoming where dry conditions persist, when compared to last year at this time, is less than half what it was.

The drought-defying portion of Montana — following a particularly wet summer and fall — remains the Hi-Line, from Toole County east to Sheridan County. In a map dominated by swaths of brown and yellow that indicate different levels of drought, those Hi-Line counties are a sea of blue.

Although other counties may not be as wet as the Hi-Line, when compared to a year ago the amount of area covered under the Montana drought forecast is half what it was and no areas of the state are reporting severe or extreme drought. That’s an indication that the state is slowly climbing out of two years of drought conditions, Montague said.

As temperatures rise this week in portions of Montana, following what has been an extended deep freeze, the DNRC is warning those who live along waterways about the possibilities of ice breakup that may cause jams that result in flooding.

“If we have three to five days with temperatures in the 40s, that’s when we have to worry,” Montague said.

The National Weather Service is predicting a high of 48 degrees on Wednesday in Billings and 45 on Thursday, before cooling down into the 30s by the weekend. Miles City is forecast to peak at 42 degrees on Wednesday while Livingston is expected to hit 47 on Wednesday and 45 on Thursday. Lewistown could hit 49 on Wednesday.