By Michael Howell
According to Ray Nickless of the National Weather Service, western Montana and north central Idaho experienced record setting amounts of rain last October and are enjoying a pretty wet spring that has brought abundant moisture to the region. Total precipitation levels in the region, snow and rain combined, are ranging from 115% to 180% of average. Between October 2016 and March 2017, the Missoula area received 9.94 inches of precipitation, which is 184% above average. Kalispell, at 13.69 inches, was 186% above average.
“Precipitation-wise it’s been a real nice flow of moisture which has gotten us out of any sort of drought related situation,” said Nickless. The above average precipitation did come with some flooding and a few homes were damaged in the Bitterroot Valley but for the most part, he said, it has been a lot of road damage. He said it was the road damage that was really adding up in terms of damages and costs.
While the amount of total precipitation is way up above average, according to Nickless, the snowpack in the region is sitting at about average, ranging from 90% to 110% across the region due to late autumn and early spring rains. However, total snowfall for the region was up. Between October 2016 and early April 2017, the Missoula area received 63.7 inches of snow or about 174% of normal. The Kalispell area received 89.8 inches or about 161% of average.
With more snow accumulating in the lower elevations and warm temperatures this spring, the initial runoff has boosted stream flows in the Bitterroot for this time of year. At this point in time, measurements on the Clearwater and the Clark Fork are showing flow levels about twice what they normally are at this time of year. Some minor flooding is predicted for the Salmon River, the Flathead River and the Yaak River near Troy. Elsewhere, according to Nickless, the flooding potential will depend on the level of spring rains and warming temperatures.
Nickless said that this was all pretty good news for irrigators and fisheries. He said the forecast was also promising. Although the month of April is forecast to be equal chances of any type of temperature and precipitation regime above or below average, in the period including May, June and July, although there is an equal chance of any kind of temperature regime, there are better chances of above normal precipitation, especially in eastern Montana but some in western Montana as well. For the late summer stretch from July through August and September, however, both the temperatures and the precipitation are forecast to be above average.
“It could be good news if we move into a more showery regime for the summer,” said Nickless. “It could dampen the fire season. We’ll have to see how that pans out.”
In summary, he said, we can expect average to above average water supplies with some minor potential for flooding in a few basins, but higher impact flooding could occur if rains in May and June combine with the snowmelt.