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Snowpack More Than Doubles in Western Montana During January

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Posted at 1:18 PM, Feb 06, 2020
and last updated 2020-02-06 15:18:30-05

BOZEMAN, Mont., February 6, 2020 – Abundant moisture spilled into the Treasure State from the Pacific during January, boosting snowpack in all river basins to near or above normal for February 1. In some locations, the amount of water added to the snowpack was record setting. Between December 30 and February 1, SNOTEL (SNOwpack TELemetry) sites west of the Continental Divide received up to 18 inches of snow water equivalent, roughly proportionate to 100 to 150+ inches of snowfall. Five SNOTEL sites would go on to set new records for monthly totals, and four SNOTEL sites reported their second highest on record.

“November and December were particularly dry, resulting in snowpack totals on January 1st that were well below normal in the river basins west of the Divide. The near continuous snowfall and moisture during January was extraordinary, and it helped the river basins to bounce back to near or above normal for snowpack on February 1st. It was quite the month,” said Lucas Zukiewicz, USDA Natural Resources Conservation Service water supply specialist for Montana.

“Although snowfall wasn’t record-setting in river basins east of the Divide, it was near to above normal for the month, helping the snowpack to improve in most areas,” said Zukiewicz. Southwest Montana experienced some of the most dramatic increases with the Jefferson and Madison River basins improving from below normal to near normal for snowpack on February 1. The West Yellowstone area, where mountain snowpack feeds the reservoirs supplying water to the Madison River, was well below normal on Janaury 1. “The mountains above Hebgen Lake received significant snowfall this month, helping to not only improve conditions for winter recreation, but water supply prospects this spring and summer,” said Zukiewicz.

South-central mountain ranges experienced slight increases in snowpack percentages during the month, while north central mountain ranges had a slight decrease from well above normal. “This region had been benefitting from early October snowpack which remained on the ground, keeping snowpack totals near to slightly above normal on January 1st, and it remains there at this time,” according to Zukiewicz.

At this point in the winter, around 60% to 70% of the seasonal peak snowpack has typically accumulated in river basins west of the Divide, while 55% to 65% of the seasonal peak snowpack has accumulated east of the Divide. “The coming months will tell us just how full the mountain snowpack “reservoir” is before spring runoff, and early February looks favorable for continued snowfall. Hopefully this wet pattern persists, and we can put some more water in the bank,” said Zukiewicz.

Monthly Water Supply Outlook Reports can be found at the website below after the fifth business day of the month: https://www.nrcs.usda.gov/wps/portal/nrcs/mt/snow/ [lnks.gd]

February 1, 2020, Snow Water Equivalent

River Basin

% of Normal

Monthly Change

% Last Year

Columbia
105
+20%
122
Kootenai, Montana
112
+23%
138
Flathead, Montana
109
+12%
133
Upper Clark Fork
100
+15%
102
Bitterroot
98
+27%
113
Lower Clark Fork
100
+35%
119
Missouri
101
+7%
109
Jefferson
99
+11%
109
Madison
94
+15%
113
Gallatin
101
+8%
95
Headwaters Mainstem
110
+15%
99
Smith-Judith-Musselshell
109
+3%
108
Sun-Teton-Marias
110
-12%
138
St. Mary-Milk
125
+12%
139
Yellowstone River Basin
104
+3%
112
Upper Yellowstone
103
+8%
108
Big Horn
112
+1%
119
Tongue
102
-5%
111
Powder
120
-8%
124
West of the Divide
105
+20%
122
East of the Divide
103
+6%
112
Montana State-Wide
104
+15%
117

February 1, 2020, Precipitation

River Basin

Monthly % of Average

Water Year % of Average

Water Year % of Last Year

Columbia
138
93
106
Kootenai, Montana
147
94
121
Flathead, Montana
141
100
112
Upper Clark Fork
122
90
95
Bitterroot
137
86
91
Lower Clark Fork
145
91
103
Missouri
108
91
96
Jefferson
115
87
96
Madison
115
84
97
Gallatin
120
97
85
Headwaters Mainstem
113
96
93
Smith-Judith-Musselshell
99
92
92
Sun-Teton-Marias
102
96
110
St. Mary-Milk
126
107
120
Yellowstone River Basin
101
93
98
Upper Yellowstone
114
95
96
Big Horn
107
100
111
Tongue
82
92
105
Powder
87
110
125
West of the Divide
138
93
106
East of the Divide
106
92
99
Montana State-Wide
125
93
101