Flood Potential Outlook
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
836
FGUS73 KABR 120825
ESFABR
MNC011-155-SDC013-017-021-025-029-031-037-039-041-045-049-051-057-
059-065-069-075-085-089-091-107-109-115-117-119-129-062000-
Probabilistic Hydrologic Outlook
National Weather Service Aberdeen SD
325 AM CDT Thu Mar 12 2026
...Spring Flood and Water Resources Outlook...
This Spring Flood and Water Resources Outlook is for the Aberdeen
Hydrologic Service Area (HSA), which covers portions of central and
northeast South Dakota, along with west central Minnesota. The main
river basins include the Missouri, James, Big Sioux, Minnesota, Bad,
Moreau, and Grand rivers.
Flooding potential remains below normal across much of the HSA,
although potential has increased slightly on the James River since
the last outlook on February 26th. Additional snow melt, along with
deep frost and added soil moisture over northern South Dakota led to
the increased potential. The James River at Columbia now has a 52
percent chance to reach minor flood stage, while the James River at
Stratford has a 56 percent chance. All other sites across the HSA
have a less than 50 percent chance of reaching minor flood stage
through the middle of June.
Below normal precipitation this winter and a lack of existing snow
cover bring a below normal flood risk this spring. While there is a
lack of snow cover, we do have frost depths of 0.5 to 2 feet across
northern South Dakota. This would bring concern for increased runoff
should a heavy spring rain event occur prior to removal of frost
from the ground. Precipitation trends into early spring will
continue to be monitored and will likely be the primary driver for
future flood outlooks.
In Table 1 below, the current (CS) and historical (HS) or normal
probabilities of exceeding minor...moderate...and major flood stage
are listed for the valid time period.
CS values indicate the probability of reaching a flood category
based on current conditions.
HS values indicate the probability of reaching a flood category
based on historical or normal conditions.
When the value of CS is greater than HS...the probability of
exceeding that level is higher than normal. When the value of CS is
less than HS...the probability of exceeding that level is lower
than normal.
...Table 1--Probabilities for minor...moderate and major flooding...
Valid Period:
Valid Period: 03/16/2026 - 06/14/2026
: Current and Historical
: Chances of Exceeding
: Flood Categories
: as a Percentage (%)
Categorical :
Flood Stages (FT) : Minor Moderate Major
Location Minor Mod Major : CS HS CS HS CS HS
-------- ----- ----- ----- : --- --- --- --- --- ---
:Elm River
Westport 14.0 16.0 19.0 : <5 28 <5 22 <5 9
:James River
Columbia 13.0 16.0 18.0 : 52 58 28 42 11 29
Stratford 14.0 17.0 18.5 : 56 58 22 41 6 32
Ashton 13.0 14.0 16.0 : 32 58 27 47 23 42
Redfield 20.0 22.0 25.0 : 14 45 12 44 10 42
:Snake Creek
Ashton 11.5 13.0 16.0 : 18 53 16 53 12 43
:Turtle Creek
:Big Sioux River
Watertown 10NW 10.0 11.0 12.0 : <5 18 <5 <5 <5 <5
Watertown Conifer 9.0 10.0 12.0 : <5 37 <5 28 <5 <5
Watertown Broadwy 10.5 11.0 13.5 : <5 35 <5 34 <5 <5
Castlewood 9.0 11.0 16.0 : 8 35 <5 28 <5 <5
:Grand River
Little Eagle 15.0 17.0 21.0 : <5 27 <5 19 <5 7
:Moreau River
White Horse 21.0 23.0 25.0 : <5 22 <5 17 <5 11
:Bad River
Fort Pierre 21.0 25.0 27.0 : 6 12 <5 5 <5 <5
:Little Minnesota
Peever 17.0 22.0 24.0 : 24 25 <5 <5 <5 <5
:Minnesota River
Big Stone Lake 970.0 971.5 973.5 : <5 6 <5 <5 <5 <5
Legend
CS = Conditional Simulation (Current Outlook)
HS = Historical Simulation
FT = Feet
In Table 2 below...the 95 through 5 percent columns indicate the
probability of exceeding the listed stage levels (FT) for the valid
time period.
...Table 2--Exceedance Probabilities...
Chance of Exceeding Stages
at Specific Locations
Valid Period:
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Elm River
Westport 5.0 5.0 5.1 5.9 8.3 11.3 13.0
:James River
Columbia 11.0 11.1 11.5 13.1 16.4 18.1 19.1
Stratford 12.4 12.6 12.7 14.3 16.6 17.8 19.2
Ashton 8.0 8.1 8.8 11.1 14.7 17.3 26.2
Redfield 7.3 7.4 8.1 10.5 14.2 24.5 31.5
:Snake Creek
Ashton 2.5 2.5 2.8 5.5 8.9 16.7 19.6
:Turtle Creek
:Big Sioux River
Watertown 10NW 4.4 4.4 4.7 6.4 7.1 8.2 8.8
Watertown Conifer 4.5 4.5 4.7 5.5 6.3 7.4 8.2
Watertown Broadwy 5.2 5.2 5.4 6.3 7.3 9.0 9.9
Castlewood 5.1 5.2 5.3 6.2 7.1 8.8 9.8
:Grand River
Little Eagle 3.8 3.9 5.0 6.4 8.3 9.0 10.6
:Moreau River
White Horse 2.7 4.0 6.6 7.9 11.2 13.9 17.1
:Bad River
Fort Pierre 0.5 1.7 3.5 6.2 12.6 19.6 23.0
:Little Minnesota
Peever 13.5 13.7 14.0 15.0 16.8 18.3 20.5
:Minnesota River
Big Stone Lake 966.5 966.5 966.5 966.5 967.1 968.6 969.8
In Table 3 below...the 95 through 5 percent columns indicate the
probability of falling below the listed stage levels (FT) for
the valid time period.
...Table 3--Nonexceedance Probabilities...
Chance of Falling Below Stages
at Specific Locations
Valid Period:
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Elm River
Westport 4.5 4.5 4.4 4.3 4.3 4.2 4.2
:James River
Columbia 9.1 9.0 7.7 6.6 6.4 6.3 6.2
Stratford 11.2 11.1 9.5 8.6 8.3 8.2 8.2
Ashton 7.5 7.5 6.6 5.6 4.9 4.8 4.8
Redfield 6.9 6.9 6.7 5.8 5.0 4.9 4.9
:Snake Creek
Ashton 2.2 2.0 1.8 1.7 1.5 1.5 1.5
:Turtle Creek
:Big Sioux River
Watertown 10NW 3.9 3.7 3.7 3.7 3.7 3.7 3.7
Watertown Conifer 4.2 4.2 4.2 4.2 4.2 4.2 4.2
Watertown Broadwy 5.0 5.0 5.0 4.9 4.9 4.9 4.9
Castlewood 4.7 4.7 4.6 4.5 4.5 4.5 4.5
:Grand River
Little Eagle 3.8 3.8 3.8 3.7 3.7 3.7 3.7
:Moreau River
White Horse 2.4 2.4 2.4 2.4 2.3 2.3 2.3
:Bad River
Fort Pierre 0.5 0.5 0.5 0.5 0.5 0.5 0.5
:Little Minnesota
Peever 0.1 0.1 0.0 0.0 0.0 0.0 0.0
:Minnesota River
These long-range probabilistic outlooks contain forecast values that
are calculated using multiple season scenarios from 30 or more years
of climatological data...including current conditions of the
river...soil moisture...snow cover and 30 to 90 day long-range
outlooks of temperature and precipitation. By providing a 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 Service.
Visit our web site weather.gov/abr for more weather and water
information.
The next outlook will be issued by the end of April.
$$
TMT