Snowpack remains low despite February moisture

Laura Lundquist

(Missoula Current) Even though February brought snow almost every weekend, it wasn’t enough to help Montana’s snowpack recover from a dry early winter.

Montana’s mountain snowpack is still only 70% of what it should be at the end of February, despite the snowstorms that have recently traversed the state. So early predictions of streamflows this summer aren’t optimistic.

The mountains of the Upper Clark Fork basin are doing slightly worse with 64% while the Flathead and the Bitterroot contain around 75% of their median snowpack recorded over the past 30 years, according to the U.S. Department of Agriculture Natural Resources Conservation Service.

But those snowpack percentages are better than what most of the state had at the beginning of February. A warm, dry early winter put the state well below normal for snowpack with the mountains having received only about half of the average snowpack for Feb. 1. A few SNOTEL sites even had record-low snow amounts.

But unlike the previous months, February dropped average to above-average precipitation across the state, prompting a sigh of relief from skiers and farmers. Areas east of the Continental Divide received more moisture than the west.

The mountains of the upper Clark Fork River received 135% of the median February precipitation amounts, while the mountains of the Bitterroot and lower Clark Fork received about 112%. The Upper Missouri Basin around Helena received the most at 170% of median. The Tongue River basin south of Miles City was the only area that received less than average precipitation at only 70%.

While February brought snow, it was also warmer than average, which caused snow at lower elevations to disappear, a trend predicted by climate change scientists. In the valleys, moisture often came as rain rather than snow. While temperatures in Missoula dipped below average for about five days mid-month, the average temperature for February was 3.5 degrees above normal, according to National Weather Service data.

The low snow amounts and warmer temperatures have caused Montana’s drought to deepen. As of Feb. 27, 95% of the state is either abnormally dry or drought, according to the National Drought Mitigation Center. All of western Montana is in at least moderate drought, with all of the area around Missoula except for the Bitterroot Valley in severe drought. A region of the Blackfoot Valley between Bonner and Lincoln and north to Seeley Lake is in extreme drought, along with a region along the northern Continental Divide.

Montana's drought is worse than most of the West, except for New Mexico, because storms have been moving off the Pacific along the coast of California, bringing record precipitation.

On Feb. 6, downtown Los Angeles saw 4.10 inches of rain in one day, breaking the old record of 2.55 inches set in 1927. The three-day total was close to 8 inches, more than half the average annual rainfall for the area. Most of the southwest has received normal or near normal precipitation amounts for the end of February.

Meanwhile very little moisture has moved inland over Washington, so the northwestern states have received little, except for systems that extended up from the southwest. So snowpack and precipitation amounts are significantly below normal across the northwest.

A warmer, drier winter in the northern states is typical of an El Nino weather pattern, which is influenced by changes in Pacific Ocean temperature. The National Weather Service is predicting that the El Nino pattern could begin to weaken by May or June.

Over the next two weeks, precipitation across most of Montana could be slightly above normal while the west side of the state could be slightly cooler than normal. But overall, the month of March should see normal temperatures and precipitation, except eastern Montana could be slightly warmer than normal.

For that reason, the National Weather Service is predicting that drought will persist across western Montana and will continue to develop across the northern portion of the state. The three-month weather outlook predicts a good chance that temperatures in western Montana will be above average and spring precipitation will be below average.
All of this could be bad news for Montana’s streams, although it’s a little too early to call at this point.