The document discusses weather patterns and streamflow volumes for water years 2012 and the outlook for 2013 in the Clark Fork River Basin. Water year 2012 saw average to above average snowpack and streamflow due to a La Nina winter. However, it was a dry summer. An El Nino watch is in effect for winter 2013, which could bring drier conditions based on historical patterns, but the outlook remains uncertain.

1. Clark Fork River Basin
Water Year Review 2012 & Outlook 2013
by
Ray Nickless
Service Hydrologist – Missoula, MT
ray.nickless@noaa.gov
Lolo Pass Visitor Center – “La Nina” Winter 2011 Forest Fires Summer 2012

2. Overview
• Weather Pattern & Climate
(Water Year 2012)
• Streamflow volumes
(Water Year 2012)
• Weather Outlook
(Water year 2013)

3. Weather Pattern
Water Year 2012

4. La Nina - Measured 2011-2012
70 Ocean Buoys
Weather Balloons

5. La Nina 2011 – 2012
(Wintertime Pattern)

6. Snowpack La Nina Years
(Western Montana)

7. Precipitation & Temperature
2012 - Water year

8. Precipitation
2012 – Water Year
October 2011 through September 2012

9. New Record
Kalispell

10. Tied Record
Missoula
41 days without precipitation

11. Dry
Butte
Entire 2012 water year
68% of ave.

12. New Record
Pierce, ID
87 days without precipitation

13. New Record
Elk City, ID
32 days without precipitation

14. Temperatures
(Warm)
Departure from Average Temperature
October 2011 through September 2012

15. Drought
Lack of precipitation and warmer temperatures

16. Water Supply for Water Year 2012
(A look back)

17. Streamflow Volumes (April through September)
Water Year 2012
er
Blackfoot Riv
117% of ave.
f av ver
% o t Ri
e.
107 erroo
Cl
ar
11 k F
t
2% ork
Bit
of Ri
av ver
e.

18. Streamflow Volumes (April through September)
Water Year 2012
N
or
th
Fo 8
rk %
12
Fl of
at av
he e.
ad
R
iv
er
M
id
dl
e
F
12 ork
4 F
Flathead River % la
of the
127 % of ave. av ad
e. R
Hungry Horse Inflow iv
er
126 % of ave.

19. Streamflow Volumes (April through September)
Water Year 2012
Ko
o
14 tena
4% i R Libby Dam Inflow
of iver
ave 143% of ave.
.

20. Precipitation - Temperature
Water Supply Forecasts
2013 -Water year

21. Weather Forecast
Yesterday

22. Weather Forecast
This Week
Missoula
Snowbowl (Ski Area)

23. Weather Outlook
End of October through November 1st
Temperature Precipitation

24. El Nino - Watch

25. November-December-January
Weather Outlook
Temperature Precipitation

26. January-February-March
Weather Outlook
Temperature Precipitation

27. El Nino & Water Supply Forecasts

28. USGS Streamflow & Annual Departure from mean
No
rth
For
kF
lath
ead
Riv
er
M
id
dl
e
Fo
rk
Fl
at
he
ad
Ri
ve
r

29. Middle Fork Flathead River 19 El Nino years since 1950
& 12 of 19 produced low flows
or 63% of time low flows
El Nino years
El Nino Years El Nino Years

30. USGS Streamflow & Annual Departure from mean
er
Blackfoot Riv
er
Riv
oot
terr
Cl
ar
Bit
k
Fo
rk
Ri
ve
r

31. Blackfoot River 19 El Nino years since 1950
& 13 of 19 produced low flows
or 68% of time low flows
El Nino years
El Nino Years El Nino Years

32. Conclusions
– Water Year 2012
• La Nina produced average to above average
snowpack in most western MT & north central ID.
• Average to above average water supply.
• Dry summer.
– Water Year 2013
• If El Nino develops (drier winter possible).
• If El Nino does not develop (drier, wetter, or
average).