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|
|Upper Clark Fork||95||101|
|Lower Clark Fork||98||117|
|Yellowstone River Basin||140||173|
|West of the Divide||96||107|
|East of the Divide||120||138|
|March 1, 2017, Precipitation|
|River Basin||Monthly % of Average||Water Year % of Average||Water Year % of Last Year|
|Upper Clark Fork||161||108||113|
|Lower Clark Fork||209||124||123|
|Yellowstone River Basin||198||146||166|
|West of the Divide||190||120||118|
|East of the Divide||194||136||146|
|April-July 50% Exceedance Forecasts|
|River Basin||Highest Point Forecast*||Lowest Point Forecast**||Basin Avg Forecast***|
|Upper Clark Fork||115%||100%||105%|
|Lower Clark Fork||108%||98%||103%|
|Yellowstone River Basin||199%||83%||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.