Healthy April 1 Snowpack Results in Near to Slightly Above Average Streamflow Forecasts
By Moosetrack Megan

Posted: April 7, 2020

BOZEMAN, Mont., April 7, 2020 – On April 1, many low- and mid-elevation mountain snowpack monitoring locations are typically approaching their seasonal peak snowpack for the year, giving hydrologists good insight into what snowpack will yield with regards to water supply during spring and summer.

“The news is as good as we get closer to runoff season this year, aside from one small lower elevation range west of Flathead Lake, most mountain ranges in Montana have a snowpack that is near to above normal for this date, even though March snow totals were below normal in some regions,” said Lucas Zukiewicz, USDA Natural Resources Conservation Service water supply specialist for Montana.

As a whole, streamflow forecasts across the state are near to slightly above average for the April 1 through July 31 period. “Water users are encouraged to look at this month’s water supply outlook report for forecasts in their region of interest, as forecasts can vary widely within a particular river basin. A few rivers west of the Divide have forecasts that are slightly below average due to the lack of late fall and early winter precipitation, even though snowpack is near normal for this date,” said Zukiewicz. This situation is not present in all river basins within the state, but it should be noted that it has impacted runoff forecasts where it is occurring.

“As we progress further into spring, we should continue to accumulate snowpack in the high elevations in the mountains across the state, and May 1 forecasts will use a more accurate snapshot into our peak snowpack, and what that should yield with regards to our overall runoff volumes this year,” according to 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/.

April 1, 2020 Snow Water Equivalent, Precipitation, and Reservoir Storage

River Basin

Snow Water Equivalent % Normal

Precipitation
Monthly
% Avg

Precipitation
Water Year
% Avg

Reservoir Storage
% Average

Reservoir Storage
% Capacity

Columbia River Basin

108

70

93

128

63

     Kootenai in Montana

107

85

91

145

61

     Flathead in Montana

109

73

98

116

63

     Upper Clark Fork

105

58

90

105

79

     Bitterroot

112

60

91

89

33

     Lower Clark Fork

104

65

89

104

96

Missouri River Basin

112

93

99

115

78

     Jefferson

109

89

96

120

64

     Madison

106

117

93

110

79

     Gallatin

115

119

114

98

54

     Headwaters Mainstem

107

78

99

118

81

     Smith-Judith-Musselshell

118

57

99

144

84

     Sun-Teton-Marias

114

86

96

109

57

     St. Mary-Milk

139

118

110

131

60

Yellowstone River Basin

113

87

100

103

58

     Upper Yellowstone

119

115

106

116

51

     Bighorn

112

77

102

99

58

     Tongue

104

44

95

178

73

     Powder

115

55

105

Montana State-Wide

111

85

97

118

72

 

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