Low snowpack portends fourth summer of drought

Laura Lundquist

(Missoula Current) Snowpack used to be Montana’s fluid money in the bank for summer. But, this year, Montana’s water savings account is in bad shape, along with that of the rest of the West.

As of the end of April, a time when snow used to blanket the mountains, snowpack statewide is only two-thirds of what it should be heading into the summer, according to the Natural Resources Conservation Service maps. Thanks to recent rain, the state has received 100% or more of its precipitation for this time of year, but rain is more temporary than snow.

When it comes to snow, the upper Clark Fork River basin is doing better than the rest of the state, containing 87% of its 30-year median snowpack for this time of year. The Bitterroot basin has around 75%, and the lower Clark Fork basin below Missoula drops to 64%. Worst off are the Bears Paw Mountains south of Havre which have no snowpack, while a little farther west, the Sun-Teton-Marias basins have a little more than half of their median snowpack.

That’s fairly similar to where Montana stood at this time last year, except the river basins of south-central and southeastern Montana had close to normal snowpack, whereas this year, they have less than 75%.

April brought an average amount of precipitation around Missoula, but to the north and east, cities like Butte and Kalispell received 161% of their average monthly precipitation, thanks to a four-day system that passed through late in the month. But Missoula and Butte were also 1 degree warmer than average for the month, so not enough of the precipitation fell as snow.

April's rain and warm temperature caused rivers in western Montana to have higher than average flows after a winter when many were lower than average. But that wasn’t the case on the eastern side of the Continental Divide, where most rivers had average to below-average flows. Streams in the Jefferson, Milk, Tongue and Powder basins had less than 75% of their average volume.

And when you drill down below the basin level, some western Montana rivers are already dropping low, according to U.S. Geological Survey data. For example, the Clark Fork River has average volume below Drummond but the sections above Drummond are flowing below normal. The Big Hole River above Wisdom is also low, but it gets better below Wisdom as tributaries add more water.

Even though some rivers are flowing well now, the low snowpack means all rivers could drop quickly and run low throughout the summer, especially if May and June bring less precipitation and more heat. And that could happen with the National Weather Service predicting that the El Nino weather pattern could kick in sometime between May and July.

For the month of May, the NWS outlook shows Montana has at least a 40-50% chance of warmer than normal temperatures and a 33-40% chance of below normal precipitation. Based on the three month outlook, those predictions are expected to continue through June and July.

As of April 28, most of Montana is once again in drought, according to the National Drought Mitigation Center. Since the beginning of February, the percentage of the state in drought has jumped from 56% to 94%. Only a four-county region around Missoula currently has no drought but it’s unlikely to stay that way. According to the NWS seasonal drought outlook issued April 30, drought will develop in western and portions of eastern Montana throughout the end of July while drought will persist in the rest of the state.

So it wasn’t too surprising when the East Side Fire broke out south of Red Lodge on April 20, even though, in the past, large wildfires didn't start so early. The area around Red Lodge is already in severe drought, the third level of drought intensity, and the winds on April 20 were strong, gusting to 30 mph. Fortunately, the cold front that brought precipitation to much of the state dropped temperatures in the area and brought snow, which helped slow the burn. As of May 5, the fire is 40% contained. The cause is still under investigation.

Thanks to April’s precipitation, the National Interagency Fire Center’s Wildland May 1 Fire Potential Outlook does not include Montana as a region of significant fire potential this summer. That doesn’t mean Montana won’t have its share of wildfires, just that the potential isn’t significant. And that could change if the state experiences the heat waves of a few years ago.

But Montana could get plenty of smoke because Idaho, eastern Oregon and eastern Washington do have significant fire potential predicted for July and August.

Contact reporter Laura Lundquist at lundquist@missoulacurrent.com.