Streamflow, Drought, and Water Supply Conditions
Water supply conditions as of 6/20/2018
From Jacqueline Knutson, Hydrologist, Montana Fish, Wildlife and Parks
Snowpack: The Big Hole Basin is at 113% of average; the Jefferson Basin is at 115% of average. Snowmelt this year started earlier than normal and has been rapid since it began. As we move forward into summer, this could be of concern. The promise of a record-setting snowpack delivering abundant water supply through the summer could easily turn into record-setting flows for a few months, and water shortages later in the summer much like last year. Snow disappeared rapidly in May with lots of sunshine and warm temperatures. There is still some snow at the highest elevations but the mid and lower elevation sites cleared out quickly in May. Darkhorse Lake has 29 inches of snow and 13 inches of snowater equivalent which is just below average for this date. What was shaping up to be a strong snowpack through the early summer has left us and we’re basically back to the same situation we were in this time last year. Therefore, the rest of this summer’s water season is going to rely heavily on precipitation events and our weather, rather than snowpack, will make or break river flows through the summer.
Precipitation: May precipitation was below average in most of the Jefferson Basin although along the divide there were a few spots that recorded above average precipitation. The story in May was that precipitation was very hit-or-miss. There were plenty of sunny days and early June has followed that pattern, although the last few days have been a departure from the sunshine. The Bloody Dick SNOTEL station has received 0.90 inches of rain in the last two days and some sites in Beaverhead County have seen over 2 inches of rain in the last 5 days. This has certainly benefited streamflows but precipitation is expected to be below normal for the rest of the month and into the summer.
Temperatures: A strong ridge of high pressure built up over most of the western United States this May and Montana felt the effects with above normal temperatures the entire month. Statewide, it was the warmest May since 1958.
Period of Record Monthly Climate Summary – Period of Record : 01/01/1923 to 06/09/2016
See details below from Western Regional Climate Center:
WISDOM, MONTANA (249067)
|Average Max. Temperature (F)||26.4||31.1||38.5||49.2||60.3||68.6||79.4||77.8||67.6||55.0||38.0||28.0||51.7|
|Average Min. Temperature (F)||1.2||3.3||10.8||21.2||28.7||36.1||38.2||34.7||27.8||21.3||12.3||3.6||19.9|
|Average Total Precipitation (in.)||0.70||0.52||0.74||0.95||1.64||1.96||1.09||1.03||0.99||0.83||0.76||0.77||11.97|
|Average Total SnowFall (in.)||11.8||8.3||8.6||4.5||2.5||0.5||0.0||0.0||0.5||1.9||7.8||10.8||57.0|
|Average Snow Depth (in.)||9||10||8||1||0||0||0||0||0||0||2||5||3|
Percent of possible observations for period of record.
Max. Temp.: 98.7% Min. Temp.: 98.6% Precipitation: 98.6% Snowfall: 76.4% Snow Depth: 50.3%
National Water Supply Reports
Nation-wide information for water supply and climate prediction & forecasts.
Montana Water Supply Reports
Statewide information for water supply and drought conditions. Report breaks out conditions by major basins:
Water supply and drought condition information specific to the Upper Missouri Basin:
Water Monitoring Resources from the Montana Watershed Coordination Council
Past Streamflow & Snowpack Reports