Snowpack Still on the Rise, Well Above Average, and Setting Records in Some Parts of Montana

From NRCS:

Unlike February, snowfall wasn’t record-breaking in Montana during March, but it was sufficient to keep the snowpack near to well above normal on April 1, according to snow survey data collected by the USDA Natural Resources Conservation Service (NRCS). “One thing is for sure; it’s been a snowy winter across the state of Montana,” said Lucas Zukiewicz, NRCS water supply specialist for Montana, “and there’s still more to come.”

Last month, records were set for both monthly totals for February snowfall, and for total snowpack accumulation on March 1. Many snowpack measuring locations that feed Montana’s rivers and streams remain record high for April 1. Ten SNOwpack TELemetry (SNOTEL) and snowcourse locations remain the highest on record for this date, and 12 measurement locations are the second highest on record. These sites can be found in the mountains that feed the Upper Yellowstone River, Upper Clark Fork and Missouri Mainstem River basins, where snowfall has been abundant throughout the winter months. “Although not record-setting like these regions, the snowpack in other river basins across the state is well above normal for this time of year,” Zukiewicz said.

2018 is looking to go down as one of the biggest snow years on record for some parts of the state, prompting questions on how it compares to other memorable snowpack years. “1972, 1997, 2011 and 2014 were all big winters across the state, and many are wondering how this year compares,” Zukiewicz said. “So far, the only snowpack that has topped all other water years for peak snow water contained in the snowpack is the area near Cooke City which feeds the Clark’s Fork River of the Yellowstone River.”

For the most part, the snowpack in the rest of the state hasn’t reached the levels of 1997, 2011 and 2014. “During those years, snowpack peaked at the beginning of May to early June. For now, it looks like there is still a lot of winter left to come and this year could break more records if it keeps going.” Zukiewicz said.

Long-range predictions by the National Weather Service’s Climate Prediction Center continue to forecast above average precipitation and below average temperatures through the end of April.

Due to the abundant snowfall, many measurement locations have already reached, or exceeded, the normal amount of snow water that is typically contained in the snowpack before runoff occurs, all but assuring at least normal surface water supply this spring and summer, Zukiewicz said. Long-duration volumetric streamflow forecasts issued for the April 1 – July 31 period are well above average for most stream gages in the state, and could approach record levels this spring and summer at the stream gage at Belfry, Mont., located along Clark’s Fork of the Yellowstone.

“Having a big snowpack is a double-edged sword,” Zukiewicz said. “You know there will be plenty of snowpack to feed the rivers, which is typically great news, but the uncertainty of how and when it will come out can keep you up at night.”

The coming month will be critical in determining how much water is available in the snowpack for runoff this spring, and the day-to-day and week-by-week weather patterns during May and June will determine the timing and volumes of water in Montana. Water users are encouraged to read the May 1, 2018, NRCS Water Supply Outlook Report, which will summarize the conditions that occurred over the month of April, and help water users prepare for runoff this spring and summer.

Individual point forecasts for streams and rivers can be found in the monthly NRCS Water Supply Outlook Report and should be consulted as conditions vary from basin to basin, and even within the basins themselves.

Monthly Water Supply Outlook Reports can be found at the website below after the 5th business day of the month:

https://www.nrcs.usda.gov/wps/portal/nrcs/mt/snow/waterproducts/basin/

April 1, 2018, Snow Water Equivalent

River Basin % of Normal % Last Year
Columbia 137 134
Kootenai, Montana 128 122
Flathead, Montana 136 130
Upper Clark Fork 156 170
Bitterroot 134 128
Lower Clark Fork 124 117
Missouri 133 145
Jefferson 135 134
Madison 124 118
Gallatin 130 148
Headwaters Mainstem 169 190
Smith-Judith-Musselshell 130 186
Sun-Teton-Marias 142 122
St. Mary-Milk 140 149
Yellowstone River Basin 135 102
Upper Yellowstone 152 128
Lower Yellowstone 121 85
West of the Divide 137 134
East of the Divide 133 119
Montana State-Wide 137 137

April 1, 2018, Precipitation

River Basin Monthly % of Average Water Year % of Average Water Year % of Last Year
Columbia 93 123 95
Kootenai, Montana 93 113 81
Flathead, Montana 101 129 96
Upper Clark Fork 103 130 114
Bitterroot 99 119 100
Lower Clark Fork 69 115 85
Missouri 111 119 95
Jefferson 117 111 93
Madison 121 113 82
Gallatin 113 124 98
Headwaters Mainstem 111 137 120
Smith-Judith-Musselshell 90 117 111
Sun-Teton-Marias 90 136 104
St. Mary-Milk 107 130 88
Yellowstone River Basin 98 122 83
Upper Yellowstone 99 138 95
Lower Yellowstone 98 108 72
West of the Divide 93 123 95
East of the Divide 103 121 89
Montana State-Wide 102 124 95

April-July 50% Exceedance Forecasts

River Basin Highest Point Forecast* Lowest Point Forecast** Basin Average Forecast***
Columbia 231% 107% 134%
Kootenai, Montana 124% 110% 118%
Flathead, Montana 158% 112% 131%
Upper Clark Fork 231% 148% 170%
Bitterroot 128% 113% 121%
Lower Clark Fork 144% 107% 130%
Missouri 174% 95% 125%
Jefferson 161% 95% 126%
Madison 114% 111% 113%
Gallatin 123% 115% 120%
Headwaters Mainstem 135% 128% 132%
Smith-Judith-Musselshell 174% 117% 141%
Sun-Teton-Marias 141% 99% 123%
St. Mary 123% 119% 121%
Yellowstone River Basin 194% 83% 133%
Upper Yellowstone 194% 97% 147%
Lower Yellowstone 159% 83% 119%

Note: Streamflow forecasts are issued for multiple points on rivers and streams within a major river basin and are given as a range of exceedance probabilities. Consult the individual river basin of interest to see the range of values for streams of interest.

*Highest point forecast is the highest 50% forecast of all forecast points within the basin.

**Lowest point forecast is the lowest 50% forecast of all forecast points within the basin.

***Basin average forecast is an average of all 50% forecasts within the basin.

Current Snowpack and Coming Spring Weather Critical to Summer Water Supplies

Snowfall in some locations of Montana has been record-breaking during February, resulting in snowpack totals for March 1st that are well above normal for most river basins, according to snow survey data collected by the USDA Natural Resources Conservation Service (NRCS). Twenty-five SNOTEL (SNOwpack TELemetry) stations and manual measurement locations set new records for February totals, and 21 measurements at other locations were the second highest on record.

“Abundant mountain, valley and plains snowfall this winter have Montana under a blanket of snow at the beginning of March,” said Lucas Zukiewicz, NRCS water supply specialist for Montana. “While this is great news for long-term water supply, it’s been hard on a lot of families and businesses in the plains.”

Snowpack totals are above normal in all major river basins of the state of Montana for March 1, and some measurement locations are setting records for this date. Fifteen snowpack measurement locations have set a new record for March 1, and 12 are the second highest on record. Most of these records are being set in the headwaters of the Upper Clark Fork, mountains of the Missouri Mainstem around Helena and in the headwaters of the Upper Yellowstone and Clark’s Fork of the Yellowstone River basins. While not record-setting, most other river basins have seen consistent and above normal moisture this winter due to the favorable La Nina weather patterns this winter. Many snowpack measurement locations have already reached the normal “peak,” or maximum amount of snow water contained in the snowpack, on March 1st. Zukiewicz said only one area seems to be left out of this year, the Centennial range which serves as the headwaters for the Red Rock River in southwestern Montana. It has a snowpack that remains below normal for this date.

“As we approach spring, water users across the state start to plan for the coming growing season, water supply and allocations from spring runoff of the mountain snowpack,” Zukiewicz said. “This year looks to deliver above average flows in the rivers in most locations due to the deep mountain snowpack.”

On March 1, the NRCS Montana Snow Survey began to issue forecasts for the spring and summer runoff with many locations forecasted to be above to well above average. Some forecasted volumes for rivers in south-central Montana for the April 1 through July 31 period are approaching records. “The median forecast for the Clark’s Fork at Belfry, Mont., is above the record for that location,” Zukiewicz said. “There’s going to be a lot of water coming out of the Beartooth Range this spring and summer.”

While spring is always critical to the timing and volume of water supply, Zukiewicz said he will keep a close eye on the week-to-week weather patterns over the next few months. Climatologically, the months of March through May are some of the most significant months with regards to precipitation for river basins east of the Divide, and many basins already have an above-normal snowpack. Any continued snowfall will build on the above normal snowpack and will further increase the amount of water available for runoff.

“At this point, we have pretty close to assured adequate water supply in many areas due to heavy early season snowfall,” Zukiewicz said. “As much as it pains me to say it, a normal month or two would be the best case scenario from here on out.” The NRCS Montana Snow Survey will issue the next snowpack report and updated water supply forecasts for the state on April 1, 2018. “By then we should have a good idea if this pattern is going to break or keep going.”

Individual point forecasts for streams and rivers can be found in the monthly NRCS Water Supply Outlook Report and should be consulted as conditions vary from basin to basin, and even within the basins themselves.

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

Source: NRCS

Off to a Good Start this Winter, Montana Snowpack Currently the Best in the Western U.S.

From NRCS:

The snowpack across most of the western U.S. isn’t looking good in most states, but it’s a different story in the state of Montana, according to snowpack data collected by the USDA Natural Resources Conservation Service (NRCS).

After a hot and dry summer, snowfall began at the end of September in the Treasure State, helping to alleviate fire concerns and beginning the seasonal snowpack at high elevations. Many basins began the new 2018 water year (starting Oct. 1) with at least some snow on the ground at the higher elevations, and most basins had snow at all elevations by the beginning of November. Consistent snowfall statewide during November increased snowpack totals through the third week of the month before a warm and dry period near the holiday melted some low elevation snow and slowed mountain accumulation. The early December lull in snowfall lasted through the middle of the month before the pattern made a major change.

The latter half of December brought substantial snowfall across the state and helped many basins improve from below normal in mid-December to near to well above normal on Jan. 1. During that same time, SNOTEL sites west of the Divide received up to 10.9 inches of snow water equivalent from storms, raising basin percentages in all western basins. While the most recent storm favored basins west of the Divide, basins east of the Divide also received up to 7.5 inches of snow water in south-central basins.

“The snowpack in Montana is off to a great start across the state, and it’s nice to brag about it, but it’s really important to remember that there is a lot of winter left to come,” said Lucas Zukiewicz, NRCS water supply specialist for Montana. He said typically, by this time of the year, about 40 to 50 percent of the seasonal snowpack has accumulated west of the Divide and 30 to 40 percent of the snowpack has accumulated east of the Divide.

“Really, it’s the April 1 and May 1 snow totals that mean the most for water users in Montana. By then we should have a better idea of the amount of water being stored in the statewide snowpack, and how that will impact water users during the spring and summer,” said Zukiewicz. Looking forward, Zukiewicz said the early spring months are critical when it comes to snowfall and water supply in the state, and continued consistent snowfall could put water users in a great position come the spring when the snowmelt begins. Only time will tell, he continued.

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/

Snowmelt Causes Rivers and Streams to Rise across Montana, More to Come

Rivers and streams are running high across the state of Montana from May snowmelt, and most have been above average for daily streamflows throughout the month. Data from the USDA Natural Resources Conservation Service showed that snowpack at high elevations in most basins peaked during the first week of May, but saw a rapid transition to melt shortly afterwards.

“The high pressure which dominated the weather patterns this month brought abundant sunshine, mostly dry conditions, and above average temperatures—the perfect combination for snowmelt,” said Lucas Zukiewicz, NRCS water supply specialist.

Some snow did fall in the high country over the month, adding to snowpack totals. SNOTEL (SNOwpack TELemetry) sites along and east of the Divide were treated to up to 31 inches of snow on May 18, providing one last day of powder skiing for those that were motivated to hike for it, Zukiewicz said. More importantly, he said this storm also helped to slow the snowmelt which was occurring a little quicker than normal due to the persistent warm and sunny weather.

Peak snow accumulation was above normal in many basins in the state, although a few central basins were below normal throughout the year with regards to snowpack. On June 1 many basins have snowpack in place that remains near to above normal for this date, but it has been melting faster than normal.

“To some extent, the above normal snowpack totals this year have been able to offset the rapid melt rates experienced during the month of May, leaving us near to above normal for today, but continued sunny and warm weather could move what’s left in the hills faster than we’d like to see it come out.” Zukiewicz  explained prolonged snowmelt is beneficial in many ways. It helps to keep water in the rivers later into the summer, keeps river temperatures down, and keeps water available to the irrigators in the state when demand is high.

Some basins that feed Montana from the south experienced record snowpack, causing concern over how much water would enter the rivers and reservoirs, and just how quickly the snowpack would melt out. “So far what has happened has been ideal,” Zukiewicz said. “The snowmelt spigot has been turned on and off a few times this month due to the periods of cooler weather, releasing the water in phases instead of one big push.”

With snowpack well above normal, there is still a large volume of water waiting to melt in the mountains of the Wind and Shoshone River basins. Federal and State water managers have worked diligently to plan for and manage the anticipated river flows, Zukiewicz said.

Long duration seasonal volume forecasts issued by the NRCS on June 1 indicate near to above average streamflows for the June-September period in many locations, but vary by basin. However, the weather over the next few weeks will play a critical role in the timing and magnitudes of flows in the rivers across the state of Montana through the summer. “Everyone is ready to get out and enjoy the mountains of the state, but cool and wet weather, and keeping the snow up in the hills as long as we can, will be better in the long run,” 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/

Montana Mountain Snowpack Looking Good Entering Runoff Season

Streamflow Forecasts above Average for Spring and Summer

After low flows in some of Montana’s rivers last summer caused issues for irrigators, anglers and recreationists, the spring and summer runoff this year looks to yield above average streamflows, according to snowpack data released by the USDA Natural Resources Conservation Service (NRCS).

Snowpack across the state is above normal for May 1 in all but a few sub-basins. Basins west of the Divide, which typically peak during the month of April, are all above normal with high elevations still gaining as of the end of the month. East of the Divide, where snowpack at higher elevations typically peaks a bit later towards the end of April to mid-May, also saw excellent gains during the month.

“Last month there was some concern over the lack of snowpack in some basins east of the Divide that provide irrigation and municipal drinking water, but April provided relief via abundant mountain snowfall and valley precipitation,” said Lucas Zukiewicz, NRCS water supply specialist for NRCS in Montana. “Two of these basins in southwest Montana, the Ruby River Basin and Hyalite drainages, have snowpack that is now normal for April 1.”

Abundant precipitation throughout this water year in most of Montana and healthy snowpack totals on May 1 have resulted in streamflow forecasts that are above average for most rivers in the state. In addition, the melt at higher elevations has been slightly delayed in some basins this year due to the cool and wet weather experienced during April.

“Delayed onset of snowmelt generally provides more efficient runoff and helps to keep the water in the mountains until it is needed to sustain streamflows later in the summer,” Zukiewicz said. “Over the last three years there has been early runoff of the seasonal snowpack, which has led to below average flows later in the season.” Streamflow forecasts issued by the NRCS are duration forecasts, or the total amount of water that will pass by a streamflow gauge during runoff season and do not forecast timing or magnitude of flows on any given day.

“The words ‘too much snow’ don’t come out of my mouth very often, but with regards to the snowpack in Wyoming basins, which feed the Bighorn River, it’s the case this year,” he said. Snowfall in the Wind River and Shoshone River basins has been record breaking this year, with snowpack totals over 200 percent of normal in some areas on May 1. Federal water managers have been working to make room for the water that will enter the river systems and reservoirs during runoff this year, increasing outflows from reservoirs in Montana and Wyoming. The May 1 – July 31 seasonal volume forecasts for some of the rivers in Wyoming are approaching record levels, with some over 200 percent of average. Zukiewicz said water users should anticipate above average flows for some time on the Bighorn River.

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/

May 1, 2017 Snow Water Equivalent

River Basin Percent of Normal Percent of Last Year
Columbia River Basin 119 163
 – Kootenai in Montana 121 178
 – Flathead in Montana 125 169
 – Upper Clark Fork 109 140
 – Bitterroot 122 174
 – Lower Clark Fork 124 185
Missouri River Basin 108 144
 – Jefferson 113 135
 – Madison 119 149
 – Gallatin 110 124
 – Headwaters Mainstem 90 130
 – Smith-Judith-Musselshell 83 94
 – Sun-Teton-Marias 129 379
 – St. Mary-Milk 124 200
Yellowstone River Basin 157 174
 – Upper Yellowstone 137 180
 – Lower Yellowstone 172 174
West of the Divide 119 163
East of the Divide 133 166
Montana Statewide 118 159

May 1, 2017 Precipitation

River Basin Monthly Percent of Average Water Year Percent of Average Water Year Percent of Last Year
Columbia River Basin 124 130 129
 – Kootenai in Montana 142 141 128
 – Flathead in Montana 146 136 135
 – Upper Clark Fork 105 113 119
 – Bitterroot 98 117 122
 – Lower Clark Fork 123 136 135
Missouri River Basin 126 128 125
 – Jefferson 120 119 119
 – Madison 142 141 147
 – Gallatin 154 132 127
 – Headwaters-Mainstem 97 110 110
 – Smith-Judith-Musselshell 119 110 108
 – Sun-Teton-Marias 95 125 151
 – St. Mary-Milk 105 149 123
Yellowstone River Basin 168 153 150
 – Upper Yellowstone 140 145 154
 – Lower Yellowstone 181 161 152
West of the Divide 124 130 129
East of the Divide 137 137 138
Montana Statewide 130 132 131

May-July 50% Exceedance Forecasts

River Basin Highest Point Forecast* Lowest Point Forecast** Basin Avg Forecast***
Columbia 152% 102% 126%
Kootenai, Montana 145% 124% 131%
Flathead, Montana 152% 117% 135%
Upper Clark Fork 136% 102% 125%
Bitterroot 117% 108% 112%
Lower Clark Fork 130% 119% 125%
Missouri 125% 78% 109%
Jefferson 125% 92% 109%
Madison 116% 111% 114%
Gallatin 108% 101% 105%
Headwaters Mainstem 113% 108% 111%
Smith-Judith-Musselshell 94% 78% 86%
Sun-Teton-Marias 119% 93% 112%
St. Mary 125% 124% 124%
Yellowstone River Basin 244% 94% 153%
Upper Yellowstone 167% 94% 134%
Lower Yellowstone 244% 125% 172%

Note: Streamflow forecasts are issued for multiple points on rivers and streams within a major river basin and are given as a range of exceedance probabilities. Consult the individual river basin of interest to see the range of values for streams of interest.

*Highest point forecast is the highest 50% forecast of all forecast points within the basin.

**Lowest point forecast is the lowest 50% forecast of all forecast points within the basin.

***Basin average forecast is an average of all 50% forecasts within the basin.

From: Natural Resources Conservation Service

Snowy February Improves Snowpack in Montana and Streamflow Prospects for Spring

 BOZEMAN, Mont., March 7, 2017 – February brought a notable change to the weather patterns that were experienced during the month of January, according to snowpack data collected by the USDA Natural Resources Conservation Service, Montana.

 

Record breaking snowfall for the month of February was experienced in northern and southern river basins of the state during the first two weeks of the month. Snow blanketed the Rocky Mountain Front at the beginning of the month, with low elevations and valleys receiving more than 3 feet of snow. Flattop Mountain SNOTEL (snow telemetry) site in Glacier National Park set a new record for February snowfall and received 12.5 inches of snow water during the month, well above the 30 year normal of 5.3 inches for February. Further south, Cooke City received copious amounts of snow, prompting the first ever “Extreme” avalanche warning for the area when Fisher Creek SNOTEL received 10.9 inches of snow water between Jan. 31 and Feb. 11. Statewide, 12 SNOTEL sites set new records for February totals, and six sites were second highest.

 

Lucas Zukiewicz, NRCS water supply specialist for Montana, said all basins experienced substantial improvements over the month with many now at near to above normal for March 1, and most basins are also near to above last year at this time. “There are some sub-basins that remain below normal for this date due to the late onset of snowpack this year and sub-par November and January snowfall,” Zukiewicz said. “One major basin is still recovering from near record low early season snow; the Smith-Judith-Musselshell will be reliant on spring precipitation to make up ground before spring and summer runoff.”

 

February typically isn’t one of the “big” snow months for Montana, he said, but this year proved otherwise. As we make the transition into spring, precipitation is favored along and east of the Continental Divide.

 

“Near normal conditions on this date is great news, but there is still a month to a month and a half before snowpack generally peaks in the mountains of Montana,” Zukiewicz said. “The coming months and their weather patterns will play a critical role in the timing and magnitudes of water in the rivers this coming spring and summer.”

 

Streamflow forecasts across the state reflect the near to above normal snowpack in many basins, and above average water year-to-date (Since Oct 1, 2016) precipitation. Many forecast points are near to above average for many rivers and streams for the April – July time period, but some remain below average due to lack of seasonal snowpack in some central Montana basins. Detailed forecasts for 98 streams in Montana can be found in the March 1st, 2017 Water Supply Outlook Report.

 

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/

 

March 1, 2017, Snow Water Equivalent
River Basin % of Normal % Last Year
Columbia 96 107
Kootenai, Montana 97 113
Flathead, Montana 97 109
Upper Clark Fork 95 101
Bitterroot 99 105
Lower Clark Fork 98 117
Missouri 100 109
Jefferson 103 97
Madison 113 126
Gallatin 98 108
Headwaters Mainstem 100 97
Smith-Judith-Musselshell 77 73
Sun-Teton-Marias 115 185
St. Mary-Milk 98 151
Yellowstone River Basin 140 173
Upper Yellowstone 128 147
Lower Yellowstone 152 197
West of the Divide 96 107
East of the Divide 120 138
Montana State-Wide 102 113
March 1, 2017, Precipitation
River Basin Monthly % of Average Water Year % of Average Water Year % of Last Year
Columbia 190 120 118
Kootenai, Montana 215 130 114
Flathead, Montana 193 125 124
Upper Clark Fork 161 108 113
Bitterroot 166 106 108
Lower Clark Fork 209 124 123
Missouri 186 131 132
Jefferson 183 122 122
Madison 201 140 151
Gallatin 164 129 126
Headwaters Mainstem 173 117 119
Smith-Judith-Musselshell 158 114 108
Sun-Teton-Marias 220 123 154
St. Mary-Milk 222 159 145
Yellowstone River Basin 198 146 166
Upper Yellowstone 207 145 153
Lower Yellowstone 196 149 182
West of the Divide 190 120 118
East of the Divide 194 136 146
Montana State-Wide 189 128 128
April-July 50% Exceedance Forecasts
River Basin Highest Point Forecast* Lowest Point Forecast** Basin Avg Forecast***
Columbia 143% 93% 104%
Kootenai, Montana 107% 100% 105%
Flathead, Montana 143% 93% 110%
Upper Clark Fork 115% 100% 105%
Bitterroot 102% 94% 99%
Lower Clark Fork 108% 98% 103%
Missouri 129% 58% 102%
Jefferson 129% 82% 106%
Madison 122% 108% 115%
Gallatin 101% 91% 96%
Headwaters Mainstem 106% 100% 104%
Smith-Judith-Musselshell 89% 58% 74%
Sun-Teton-Marias 119% 85% 106%
St. Mary 113% 110% 111%
Yellowstone River Basin 199% 83% 118%
Upper Yellowstone 148% 83% 119%
Lower Yellowstone 199% 90% 118%

Note: Streamflow forecasts are issued for multiple points on rivers and streams within a major river basin and are given as a range of exceedance probabilities. Consult the individual river basin of interest to see the range of values for streams of interest.

*Highest point forecast is the highest 50% forecast of all forecast points within the basin.

**Lowest point forecast is the lowest 50% forecast of all forecast points within the basin.

***Basin average forecast is an average of all 50% forecasts within the basin.

 

NRCS: Montana Water Users Prepare For Low Streamflow

After a disappointing winter, Montana water users should prepare for early, below average snowmelt runoff in streams

BOZEMAN, Mont., NRCS— Warm and dry weather patterns persisted through April. Mid and high elevations peaked during the month before transitioning to melt during the last two weeks, according to snowpack data from the USDA Natural Resources Conservation Service (NRCS).

“After high hopes that the weather patterns would turn around month after month, it turned out to be a disappointing year, snowfall-wise, in Montana,” said Lucas Zukiewicz, NRCS water supply specialist for Montana.

Snowpack conditions vary widely across the state, even within river basins. Towards the end of March or early April, low elevation measurement locations melted. Higher elevations retained the early season snow through the winter, experiencing near to slightly below normal snowpacks until the end of April. At 57 percent of normal for May 1, the Missouri River basin currently has the lowest snowpack out of the three major river basins across the state. Substantial declines, due to melt and lack of precipitation, have greatly reduced the snowpack since March 1. Currently, the Yellowstone River basin has the highest percentage of normal snowpack, but it is still only 71 percent of normal for May 1. The Columbia River basin snowpack is currently 61 percent of normal for this date.

may 1 snow water equivalent nrcs

“This year, not only did our snowpacks peak below normal, they also began the runoff season ahead of schedule as well,” Zukiewicz said.  “For water users across the state, this generally means that runoff will occur earlier this year, and when it does, there will be less water.”

Streamflow Forecasts

Aside from the Columbia River basin, where above average precipitation fell in the form of rain this winter, streamflow prospects this spring and summer generally reflect the lack of snowfall. Streamflow forecasts range from near record low (42%) in the Jefferson River basin in southwest Montana to below average (80-87%) on the mainstreams of the Flathead and Kootenai River basins.

This season, river systems that do not contain reservoirs for storage, such as the Gallatin and Upper Yellowstone, will see low streamflows pass through ahead of schedule.   For water users on rivers systems with reservoirs, there is water from last year’s runoff.  Because of last year’s record-breaking snowfall, carryover runoff was stored, leaving most reservoirs near to above average for May 1.

Water year-to-date precipitation (October 1 – May 1) across the state is near to slightly below normal for this time, with the exception of southwest Montana. Precipitation this spring and summer will play a critical role in the volume of runoff experienced this year. East of the Divide, where overall precipitation conditions have been drier this year, May and June are favored for rain and high elevation snow.

“We are coming up on what is typically known as ‘mud season’ in the Montana mountains,” Zukiewicz said.”Usually, people dread this season, but this year I think many will welcome any spring and summer rain, just to have a mud season.”

Conditions vary widely within the river basins this year. For detailed information on individual basin conditions and streamflow forecast points refer to the May 1 Water Supply Outlook Report.

Below are the averaged river basin streamflow forecasts for the period April 1 through July 31. THESE FORECASTS ASSUME NEAR NORMAL MOISTURE AND RUNOFF CONDITIONS MAY THROUGH JULY.

may-june streamflow forecast period

Press Release USDA NRCS. Follow us on Twitter @NRCS_MT.