Record low snow depth reported as Montana dries up
Micah Drew
(Daily Montanan) Despite a strong start to the winter in Montana, snowfall stalled in January leaving much of the state significantly more barren than typical for this time of year.
With a plea to Punxsutawney Phil’s prediction of six more weeks of winter, hydrologists with the U.S. Department of Agriculture Natural Resources Conservation Service warn that while there is still time for Montana’s snowpack to recover, most of the western river basins are reporting well below average numbers.
“Most Montana basins are now reporting below normal snowpack,” Florence Miller, a hydrologist with NRCs said in a press release. “While some higher elevations are holding onto their snowpack reserves, mid elevation snowpack is falling behind, and low elevation snowpack is noticeably absent.”
According to the latest NRCS Water Supply Outlook Report published at the start of February, most major river basins saw between a 10% and 30% decrease from a month ago, when higher elevations were at or exceeding 20-year medians.
Throughout January accumulated precipitation was well below normal, with three SNOTEL data collection sites receiving less than 30% of the monthly median.
Across the west, 30 SNOTEL sites across the western half of the state are recording the lowest snow depth on record, while another 44 sites are experiencing the second lowest.
However, the NRCS report notes that snow depth does not directly correlate to the snow water equivalent in the snowpack, a measure of how much water is stored in the snow forming the basis of a basin’s water supply, which will eventually melt into the rivers.
“Although water content is low, it is not record-breaking,” the report states.
Snowpack in Montana’s mountains at the start of the month ranged from 65% to 100% of the 20-year median, with an outlier in the Bear Paw Mountains, which is sitting at just 46% of normal.
The Bighorn and Upper Yellowstone basins are faring the best in the state, at 98% of normal, while the Flathead, Upper Clark Fork and Upper Missouuri basins are all between 80 and 84%.
Similar to data collected at the end of December, which saw an atmospheric river dump record-breaking rain across lower elevations and decent snowfall at upper elevations, there are major differences in snowpack within river basins.
In the Whitefish range, for example, the Stahl Peak SNOTEL site is reporting 24.5 inches of SWE — 111% of median — while the lower elevation Grave Creek site has only 4.4 inches — 41% of median.”
“Mid- to high-elevation snowpack is the main contributor to summer streamflow,” Miller said. “How the lack of low elevation snow coverage will influence snowmelt driven runoff this year is yet to be determined.”
With most sites sitting at less than half the median snowpack, “a return to winter and continued snowfall will be crucial to catch up,” according to the report.
A return to winter would mean a return to significantly colder temperatures.
Throughout January, most areas in Montana were three to nine degrees Fahrenheit above normal with some areas in central Montana climbing close to 12 degrees higher than normal.
The NRCS report showed that lower elevation areas experienced abnormal snowmelt during the warm spell, and future temperatures remaining at or below normal will be “critical” for delaying further snowmelt.
Along with the warm temperatures, the U.S. Drought Monitor shows that the state saw an 10% increase in areas experiencing drought conditions during the last month, with 63% of Montana under some level of drought.
Beginning next month, the department will begin publishing its official water supply forecasts as the snowpack accumulation gets closer to its peak, which will give experts a better look at what early-season streamflows will look like.
The report notes that Montana’s mountains typically reach peak snowpack accumulation between late March and early May, according to hydrologists, which means there is still time to recover from the current deficits, but “the larger they grow, and the shorter the time to catch up, the less likely full recovery becomes.”
“There is still time for the snowpack to recover, and with any luck from the shadow of Punxsutawney Phil, the grasses and shrubs … may finally disappear for the winter,” the report states.