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News Release

Storms pass south again this month, resulting in decreased Montana snowpack percentages on Feb 1

Contact:
Lucas Zukiewicz
406-587-6843


BOZEMAN, Mont., Feb. 6, 2017— Hit or miss may be the best way to describe this winter in terms of precipitation. October and November brought well above average precipitation across Montana, while November and January were well below average with regards to mountain and valley precipitation. Two storm systems brought the bulk of the snowfall during the month, and did increase the snowpack, but not enough snow fell during these events to keep the basin snowpack percentages from falling, according to snow survey data collected by the USDA Natural Resources Conservation Service (NRCS).

Again this month, significant moisture stayed just south of most of the state, but did drop snow on the southern ranges that feed Montana’s rivers. While January wasn’t wet, it certainly was cold. Daily average temperatures through the month were well below average across the state, and temperatures plummeted below zero for extended periods at the beginning and middle parts of the month.

The lack of additional snowfall during the month in some northwest and northern basins, in addition to central basins east of the Divide, has dropped the basin snowpack totals from January 1, while some river basins along the southern border saw small increases through the month. Northern river basins received 35 to 65% of average precipitation at mountain SNOTEL locations for the month, while southern basins received 80 to 131%.

The lack of additional snowfall during the month in some northwest and northern basins, in addition to central basins east of the Divide, has dropped the basin snowpack totals from January 1, while some river basins along the southern border saw small increases through the month. Northern river basins received 35 to 65% of average precipitation at mountain SNOTEL locations for the month, while southern basins received 80 to 131%.

Most river basins are well below normal for February 1, except the Upper Yellowstone which remains slightly above normal for this date. Compared to last year, most basins have snowpack totals for February 1 that are lower than last year at this time. The Upper Yellowstone and Sun-Teton-Marias river basins have slightly higher snowpack totals, and the Lower Yellowstone in Wyoming is well above last year on February 1.

“Fortunately, as February began, a return to more favorable storm patterns brought snow to the state,” Zukiewicz said. Looking ahead, he said February typically is one of the drier months with regards to mountain snowfall across the state. Northwest river basins are generally favored with early winter precipitation, while basins east of the Divide are favored during the spring months. “This has been anything but a typical La Nina winter so far, and anything can happen in the coming months,” Zukiewicz said.

By February 1, 55% to 65% of Montana’s annual peak snowpack has typically accumulated. "Given that snowpack totals are below normal in most basins, above average snowfall during the rest of the winter and through the spring will be needed to expect average water supply this summer, ” Zukiewicz said.

Monthly Water Supply Outlook Reports can be found here after the 5th business day of the month: http://www.nrcs.usda.gov/wps/portal/nrcs/main/mt/snow/waterproducts/basin/

Snow Water Equivalent

February 1, 2017 Snow Water Equivalent
River Basin Percent of Normal Percent of Last Year
Columbia River Basin 76 85
Kootenai, Montana 71 84
Flathead, Montana 77 92
Upper Clark Fork 77 79
Bitterroot 78 85
Lower Clark Fork 64 73
Missouri River Basin 80 81
- Jefferson 79 71
- Madison 87 92
- Gallatin 78 80
Headwaters Mainstem 85 77
Smith-Judith-Musselshell 62 59
Sun-Teton-Marias 82 132
St. Mary-Milk 73 106
Yellowstone River Basin 115 149
Upper Yellowstone 104 116
Lower Yellowstone 125 184
West of the Divide 76 85
East of the Divide 97 111
Montana Statewide 80 87

Feb. 1, 2017 Precipitation

River Basin Monthly Percent of Average Water Year Percent of Average Water Year Percent of Last Year
Columbia 48 105 105
Kootenai, Montana 37 115 102
Flathead, Montana 44 110 113
Upper Clark Fork 60 96 100
Bitterroot 49 90 94
Lower Clark Fork 46 105 107
Missouri 81 120 118
- Jefferson 83 108 104
- Madison 91 129 133
- Gallatin 80 122 114
Headwaters Mainstem 84 106 107
- Smith-Judith-Musselshell 67 105 98
- Sun-Teton-Marias 60 103 130
St. Mary-Milk 50 149 139
Yellowstone River Basin 118 135 153
Upper Yellowstone 99 131 131
Lower Yellowstone 136 140 179
West of the Divide 48 105 105
East of the Divide 93 124 132
Montana Statewide 67 115 115