Latest Spring Flood Outlook

Below is the latest 90-day probabilistic flood outlook for the region. Despite the recent rains and snows, most areas have less than normal chances of hitting flood stage this spring due to the very dry conditions across the area from lates last summer through early this winter.

We would appreciate your comments on our Spring Flood and Water Resources Outlook product. A very short survey can be taken here.

PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE SIOUX FALLS SD
730 AM CST THU MAR 1 2012


...ADVANCED HYDROLOGIC PREDICTION SERVICES (AHPS) ENABLE THE
NATIONAL WEATHER SERVICE TO PROVIDE LONG-RANGE PROBABILISTIC RIVER
OUTLOOKS...


THIS OUTLOOK IS VALID FROM MAR 4 2012 - JUN 2 2012


THE FOLLOWING TABLE GIVES THE CHANCE OF REACHING DIFFERENT
FLOOD LEVELS AT THE GAGES DURING THE VALID PERIOD.


                                         APPROXIMATE CHANCE OF
                 FLOOD LEVELS (FT)       REACHING FLOOD LEVELS
LOCATION         MINOR MODRT MAJOR       MINOR  MODRT  MAJOR
--------         ----- ----- -----       -----  -----  -----
JAMES RIVER
HURON SD        11.0  13.0  15.0        35%    25%    20%
FORESTBURG SD   12.0  14.0  16.0        40%    25%    10%
MITCHELL SD     17.0  20.0  22.0        40%    25%    10%
SCOTLAND SD     13.0  14.0  16.0        30%    25%    20%
YANKTON SD      12.0  14.0  16.0        25%    20%    10%

FIRESTEEL CREEK
MT VERNON SD     8.0  13.0  15.0        30%    10%    <5%

W FK VERMILLION RIVER
PARKER SD        9.0  10.0  11.0        <5%    <5%    <5%

E FK VERMILLION RIVER
PARKER SD       12.0  15.0  16.0         5%     5%    <5%

VERMILLION RIVER
DAVIS SD        11.0  13.0  15.0        15%     5%    <5%
WAKONDA SD      14.0  15.5  17.0        15%    15%     5%
VERMILLION SD   21.0  22.0  30.0         5%     5%    <5%

BIG SIOUX RIVER
BROOKINGS SD     9.0  10.5  12.0        55%    35%    10%
DELL RAPIDS SD  12.0  14.0  15.0        35%    15%    10%
S FALLS 60TH ST 12.0  14.0  16.0        30%    15%     5%
SF CLIFF AVE    16.0  18.0  31.0        25%    15%    <5%
HAWARDEN IA     15.0  20.0  23.0        65%    15%    <5%
AKRON IA        16.0  18.0  20.0        55%    35%    15%
SIOUX CITY IA   99.0 105.0 108.0        <5%    <5%    <5%

SKUNK CREEK
SIOUX FALLS SD  11.5  15.0  17.0        <5%    <5%    <5%

SPLIT ROCK CREEK
CORSON SD        8.5  11.0  14.0        40%    20%     5%

ROCK RIVER
LUVERNE MN      10.0  12.0  14.0         5%    <5%    <5%
ROCK RAPIDS IA  13.0  16.0  19.0        40%    20%     5%
ROCK VALLEY IA  16.0  17.0  19.0        10%    <5%    <5%

FLOYD RIVER
SHELDON IA      12.0  14.0  16.0        10%    10%    <5%
ALTON IA        12.0  16.0  18.0        10%    <5%    <5%
LEMARS IA       20.0  21.0  24.0        <5%    <5%    <5%
STRUBLE IA      14.0  15.0  16.0        <5%    <5%    <5%
MERRILL IA      12.0  14.0  16.0        <5%    <5%    <5%
JAMES IA        26.0  30.0  34.0        <5%    <5%    <5%

PERRY CREEK
SIOUX CITY IA   24.0  26.0  28.0        <5%    <5%    <5%

OCHEYEDAN RIVER
SPENCER IA       8.0   9.5  10.5        25%     5%     5%

LITTLE SIOUX RIVER
SPENCER IA      10.0  14.0  16.0        50%     5%    <5%
LINN GROVE IA   18.0  19.5  21.0        35%    15%     5%
CHEROKEE IA     17.0  21.0  24.0        20%     5%    <5%
CORRECTIONVILLE 19.0  20.0  21.0        10%    <5%    <5%

WEST FORK DITCH
HORNICK IA      20.0  22.0  27.0        15%    10%    <5%

REDWOOD RIVER
MARSHALL MN     14.0  15.0  16.5         5%     5%    <5%

DES MOINES RIVER
JACKSON MN      12.0  14.0  16.0        10%    <5%    <5%


IN THE TABLE BELOW...THE 90 THROUGH 10 PERCENT COLUMNS INDICATE THE
CHANCE THE RIVER COULD RISE ABOVE THE LISTED STAGE LEVELS IN THE
NEXT 90 DAYS. EXAMPLE: THE JAMES RIVER NEAR SCOTLAND HAS A FLOOD
STAGE OF 13 FEET. THERE IS A 30 PERCENT CHANCE THAT THE RIVER WILL
RISE ABOVE 12.8 FEET IN THE NEXT 90 DAYS.


LOCATION        FS(FT) 90%  80%  70%  60%  50%  40%  30%  20%  10%
-----------     ----   ---  ---  ---  ---  ---  ---  ---  ---  ---
JAMES RIVER
HURON           11.0   9.4  9.5  9.7 10.0 10.5 10.9 12.2 14.7 17.2
FORESTBURG      12.0   6.6  6.6  7.3  8.5  9.9 11.0 13.4 15.2 15.8
MITCHELL        17.0  12.0 12.0 12.4 13.4 14.9 16.3 18.2 20.9 22.2
SCOTLAND        13.0   5.8  5.8  6.1  6.8  8.6 11.2 12.8 15.7 17.3
YANKTON         12.0   4.3  4.3  4.7  5.3  6.3  7.6  9.4 13.3 16.7

FIRESTEEL CREEK
MOUNT VERNON     8.0   2.1  2.1  3.2  4.7  6.1  7.4  8.4  9.4 13.1

WEST FORK VERMILLION RIVER
PARKER           9.0   0.8  0.9  1.2  1.5  1.6  2.0  2.2  2.6  3.3

EAST FORK VERMILLION RIVER
PARKER          12.0   4.1  4.7  5.5  5.9  6.2  7.4  8.9 10.4 11.3

VERMILLION RIVER
DAVIS           11.0   3.0  4.0  5.3  5.7  6.4  7.6  9.3 10.9 11.7
WAKONDA         14.0   4.1  4.7  5.7  6.1  6.7  8.9 10.9 12.6 16.0
VERMILLION      21.0   3.9  4.5  5.4  6.0  6.6  8.6 10.7 12.3 16.3

BIG SIOUX RIVER
BROOKINGS        9.0   5.8  6.3  7.1  8.0  9.2  9.4 10.7 11.0 12.2
DELL RAPIDS     12.0   7.0  7.4  8.1  9.4 10.9 11.8 12.6 13.3 14.8
60TH STREET     12.0   5.2  5.7  6.4  7.8  9.8 10.7 12.0 12.6 14.3
NORTH CLIFF     16.0   9.6 10.0 10.7 11.6 13.6 14.4 15.5 16.3 20.3
HAWARDEN        15.0  11.8 12.6 14.7 15.3 16.4 17.3 18.8 19.6 20.9
AKRON           16.0  11.8 12.6 14.7 15.7 16.8 17.6 18.9 19.8 21.1
SIOUX CITY      99.0  86.7 86.9 87.9 88.8 89.6 90.5 91.8 92.5 94.2

SKUNK CREEK
SIOUX FALLS     11.5   5.7  5.8  6.0  6.3  6.6  6.9  7.1  7.5  8.5

SPLIT ROCK CREEK
CORSON           8.5   4.7  5.2  5.5  6.4  7.4  8.5  9.1 11.2 12.5

ROCK RIVER
LUVERNE         10.0   4.1  4.1  4.1  4.2  4.4  4.5  4.7  5.0  5.6
ROCK RAPIDS     13.0   9.1  9.4 10.2 11.0 12.3 13.1 13.6 15.0 17.3
ROCK VALLEY     16.0   6.1  6.8  8.2  9.7 11.0 12.3 12.5 14.1 15.4

FLOYD RIVER
SHELDON         12.0   5.9  6.2  6.5  6.6  7.0  7.7  8.8 10.3 12.6
ALTON           12.0   6.6  6.8  7.1  7.3  7.7  9.0  9.6 10.6 11.9
LE MARS         20.0  11.6 12.0 12.2 12.3 12.6 13.3 14.6 15.2 15.8
MERRILL         20.0   1.4  1.6  1.7  2.0  2.4  2.8  4.0  4.5  5.1
JAMES           26.0  10.5 10.6 10.8 11.0 11.2 11.9 12.7 13.2 13.8

WEST BRANCH FLOYD RIVER
STRUBLE         14.0   5.0  5.2  5.4  5.9  6.4  7.1  7.4  8.4  9.0

PERRY CREEK
SIOUX CITY      24.0   7.5  7.7  8.0  8.1  8.1  8.3  8.4  8.9  9.5

OCHEYEDAN RIVER
SPENCER          8.0   3.0  3.1  3.5  4.0  4.4  5.6  7.2  8.6  9.1

LITTLE SIOUX RIVER
SPENCER         10.0   7.2  7.4  8.3  8.9  9.6 11.3 12.1 12.8 13.3
LINN GROVE      18.0  16.3 16.4 16.6 16.7 17.0 17.8 18.3 19.2 19.6
CHEROKEE        17.0   7.5  7.5  7.9  9.1 10.3 13.0 15.1 17.5 18.2
CORRECTIONVILLE 19.0   7.9  8.0  8.8  9.2 10.1 12.8 14.1 16.2 18.8

WEST FORK DITCH
HORNICK         20.0   9.1 10.2 11.2 11.9 12.9 15.0 16.4 17.7 21.4

REDWOOD RIVER
MARSHALL        14.0   7.5  7.8  8.0  8.2  8.5  9.1  9.3 10.1 11.8

DES MOINES RIVER
JACKSON         12.0   5.9  6.0  6.1  6.4  6.8  7.9  8.7  9.5 11.6


CURRENT SOIL CONDITIONS...CALCULATED SOIL MOISTURE ANOMALIES ARE 1
TO 2 INCHES BELOW NORMAL NEAR THE MISSOURI RIVER...AND RANGE UP TO 3
TO 4 INCHES BELOW NORMAL FROM THE BIG SIOUX RIVER BASIN EASTWARD.
THE NATIONAL DROUGHT MONITOR HAS CLASSIFIED ALL AREAS FROM THE BIG
SIOUX BASIN EAST AS BEING IN SEVERE DROUGHT...WITH MODERATE DROUGHT
IN THE JAMES AND VERMILLION BASINS. FROST DEPTHS ARE AVERAGING ONLY
2 TO 8 INCHES FROM INTERSTATE 90 SOUTH...WITH FROZEN GROUND TO
DEPTHS OF 10 TO 20 INCHES IN THE NORTHERN AREAS.


CURRENT STREAM CONDITIONS...MOST OF THE JAMES RIVER IS RUNNING NEAR
NORMAL FOR THIS TIME OF THE YEAR. FARTHER TO THE SOUTH AND EAST
ACROSS THE REST OF SOUTHEASTERN SOUTH DAKOTA...SOUTHWEST
MINNESOTA...AND NORTHWEST IOWA...STREAMFLOWS ARE RUNNING ABOVE
NORMAL DUE TO THE 1 TO 2 INCHES OF RAIN THAT FELL EARLIER THIS WEEK.
MANY STREAMS AND RIVERS ARE SEEING MUCH OF THE ICE BEING FLUSHED OUT
OF THE CHANNELS WITH THE RECENT HIGHER FLOWS.


CURRENT SNOW CONDITIONS...THE MIDDLE AND UPPER PORTIONS OF THE JAMES
RIVER BASIN...AND THE UPPER PORTION OF THE BIG SIOUX BASIN...HAVE 6
TO 12 INCHES OF SNOW ON THE GROUND...WITH WATER EQUIVALENTS OF 1 TO
2 INCHES. THERE IS ALSO AN AREA OF 2 TO 5 INCHES OF SNOW DEPTH IN
THE UPPER LITTLE SIOUX BASIN...WITH WATER EQUIVALENTS OF UP TO 1
INCH. MOST OF THE REST OF THE REGION HAS LESS THAN 2 INCHES OF SNOW
REMAINING ON THE GROUND.


THE NUMBERS CONTAINED IN THIS LONG-RANGE PROBABILISTIC OUTLOOK
REPRESENT NATURAL FLOWS. THAT IS...FLOWS UNAFFECTED BY MAN-MADE
STRUCTURES IN THE BASIN SUCH AS DIVERSION DAMS AND RESERVOIRS.


THIS LONG-RANGE PROBABILISTIC OUTLOOK CONTAINS FORECAST VALUES THAT
ARE CALCULATED USING MULTIPLE SEASON SCENARIOS FROM 30 OR MORE YEARS
OF CLIMATOLOGICAL DATA INCLUDING CURRENT CONDITIONS OF THE
RIVER...SNOW COVER...AND SOIL MOISTURE...AND THE 30 TO 90 DAY
LONG-RANGE OUTLOOKS OF TEMPERATURE AND PRECIPITATION. BY PROVIDING
THE COMPLETE RANGE OF PROBABILITIES...THE LEVEL OF RISK ASSOCIATED
WITH LONG-RANGE PLANNING DECISIONS CAN BE DETERMINED. THESE
PROBABILISTIC FORECASTS ARE PART OF THE NATIONAL WEATHER SERVICE`S
ADVANCED HYDROLOGIC PREDICTION SERVICES (AHPS).


LONG-RANGE PROBABILISTIC OUTLOOKS WILL BE ISSUED TOWARD THE END OF
THE MONTH THROUGHOUT THE YEAR. THE NEXT SCHEDULED OUTLOOK FOR THESE
SITES WILL BE ISSUED TOWARD THE END OF MARCH 2012.


VISIT OUR WEB SITE AT WWW.WATER.WEATHER.GOV/AHPS2/INDEX.PHP?WFO=FSD
FOR MORE WEATHER AND RIVER INFORMATION INCLUDING GRAPHS OF
PROBABILISTIC RIVER OUTLOOKS.

$$


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