Missouri
River Region Mountain Snowpack Report
2011-2012
Mountain Snowpack Report for Missouri River Basin
Winter of 2011-2012. The February 1 forecasted runoff for calendar year
2012 is 25.6 MAF. This runoff would be
103% of normal runoff. As of February 1,
2012, the mountain snowpack in the reach above Fort Peck is 87% of the average
snowpack for this date. Mountain
snowpack in the reach between Fort Peck and Garrison is 96% of the average
snowpack for this date. The snowpack for
the North Platte River Basin is currently 71% of average and the snowpack for
the South Platte River Basin is 78% of average.
Missouri River Basin mountain snowpack normally peaks near April 15.
The following tabulation is a
summary of this year's mountain snowpack accumulations and the CY 2012 runoff
forecast for the first of each month.
|
CY 2012
Mountain Snowpack Accumulations in Percent of Normal Peak |
||||||||
|
Drainage Basin |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
|
Above Fort Peck Dam |
79% |
87% |
- |
- |
- |
- |
- |
- |
|
Fort Peck to Garrison |
96% |
96% |
- |
- |
- |
- |
- |
- |
|
Percent of Normal
Total Acc. |
88% |
91% |
- |
- |
- |
- |
- |
- |
|
North Platte River |
75% |
71% |
- |
- |
- |
- |
- |
- |
|
South Platte River |
86% |
78% |
- |
- |
- |
- |
- |
- |
|
Forecasted CY
2012 Missouri River Basin Annual Runoff in MAF |
||||||||
|
Location |
Jan |
Feb |
Mar |
Apr |
May |
Jun |
Jul |
Aug |
|
Above
Sioux City, Iowa. |
26.5 |
25.6 |
- |
- |
- |
- |
- |
- |
|
Percent
of Normal 24.8 MAF |
107% |
103% |
- |
- |
- |
- |
- |
- |
SNOTEL Mountain snowpack station data is provided
by the National Resource Conservation Service. Normally by April 15, 100% of
the peak accumulation has occurred.
The table above labeled CY 2012 Mountain Snowpack, gives information in percent of
average for the two significant snowpack accumulation reaches of Fort Peck and
Fort Peck to Garrison. The snow melts during the May through July timeframe and
provides significant main stem inflow which is stored to prevent downstream
flooding and later used to meet main stem authorized project purposes. Even knowing the amount of snow at the first of each month for
selected mountain snowpack areas results in considerable runoff variability
because the weather conditions during the melt period greatly influences the
runoff yield. The total percent of normal accumulation are shown for the
first of each month through May. For the period of May through July the
percentages shown are a percent of the peak accumulation for the year to
indicate the remaining snow to melt in the mountains.