Flood Potential Outlook Issued by NWS Sioux Falls, SD
000
FGUS73 KFSD 151634
ESFFSD
IAC021-035-041-059-093-119-141-143-149-167-193-MNC033-063-081-083-
101-105-117-133-NEC043-051-SDC003-005-009-011-015-023-027-035-043-
053-061-067-073-077-079-083-087-097-099-101-111-125-127-135-171645-
Probabilistic Hydrologic Outlook
National Weather Service Sioux Falls SD
1034 AM CST Thu Feb 15 2024
...Spring Flood and Water Resource Outlook...
This spring flood and water resource outlook is for the Sioux Falls
Hydrologic Service Area (HSA), which covers portions of central and
southeastern South Dakota, southwestern Minnesota, northwestern Iowa
and far northeast Nebraska. The main river basins include the
Missouri, James, Big Sioux, Vermillion, Redwood, West Fork of the
Des Moines, Little Sioux, Rock, Floyd Rivers.
.Flood Outlook Summary...
A current lack of widespread substantial snow cover, largely thawed
ground, and decreasing river ice currently points toward a below
normal flood risk over the next 90 days. With this said, additional
heavy precipitation events or cold outbreaks could change the flood
risk going forward. Changes to the flood risk factors will continue
to be monitored and updates provided in future outlooks.
.Temperature and Precipitation...
Long term precipitation deficits have existed across most location
over the past several years. Recent precipitation over the past few
months has shown values closer to or even above normal. Above normal
temperatures over the past 90 days has allowed for decreasing river
ice and thawing ground.
Looking forward over the next two weeks, odds lean toward near or
above normal temperatures with near to below normal precipitation.
This should allow for good melting conditions, thus `reseting` our
snow cover to minimal values. Both medium and long range outlooks
through early May have equal odds of above/below/near normal
precipitation and temperatures.
.Snow Cover and Liquid Water Content...
Above normal temperatures eroded the vast majority of snow cover in
late January and early February. Wednesday`s snow event established
a corridor of up to 0.5 inches of snow water equivalent (SWE),
focused across areas north of I-90. Additional snow is expected late
Thursday in early Friday mainly south of I-90. Regional snow water
equivalents are below normal.
.Soil Conditions and Frost Depth...
The late autumn precipitation and an early snowmelt season have
resulted in soil moisture profiles within normal ranges, slightly
drier east of I-29 and wetter west of I-29. Soil temperature
observations reveal most locations are thawed (south of I-90) or
trending toward thawed (north of I-90) with temperatures in the
upper several layers around or above freezing.
.River and Lake Conditions...
Entering the winter freeze-up months, river levels and streamflow
for the James River and points west are generally running near to
above normal with most other locations running near to slightly
below. Reports also indicate area stock ponds and wetlands may have
adequate room for additional storage of any runoff.
.Probabilistic 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: 02/17/2024 - 05/17/2024
: 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
-------- ----- ----- ----- : --- --- --- --- --- ---
:Floyd River
Sheldon 12.0 14.0 16.0 : 6 34 <5 23 <5 <5
Alton 12.0 16.0 18.0 : 6 32 <5 15 <5 7
Le Mars 20.0 21.0 24.0 : <5 16 <5 9 <5 <5
:West Branch Floyd River
Struble 14.0 15.0 16.0 : <5 8 <5 5 <5 <5
:Floyd River
Merrill 12.0 14.0 16.0 : <5 7 <5 5 <5 <5
James 26.0 30.0 34.0 : <5 <5 <5 <5 <5 <5
:Little Sioux River
Milford 12.0 14.0 16.0 : 37 71 20 61 10 46
Spencer 10.0 14.0 16.0 : 25 63 <5 8 <5 <5
:Ocheyedan River
Spencer 8.0 9.5 10.5 : 7 35 <5 13 <5 6
:Little Sioux River
Linn Grove 18.0 19.5 21.0 : <5 34 <5 11 <5 <5
Cherokee 17.0 21.0 24.0 : 8 35 <5 6 <5 <5
Correctionville 19.0 21.0 23.0 : <5 9 <5 5 <5 <5
:West Fork Ditch
Hornick 20.0 22.0 26.5 : <5 6 <5 5 <5 <5
:Perry Creek
Sioux City 24.0 26.0 28.0 : <5 <5 <5 <5 <5 <5
:Big Sioux River
Brookings 9.0 10.5 12.0 : 15 44 <5 34 <5 14
Dell Rapids 12.0 14.0 15.0 : 6 37 <5 18 <5 16
Sioux Falls I-90 12.0 15.0 17.0 : 6 40 <5 17 <5 8
:Skunk Creek
Sioux Falls 12.0 15.0 17.0 : 6 40 <5 17 <5 8
:Big Sioux River
Sioux Falls N Cliff 16.0 18.0 31.0 : 5 22 <5 18 <5
<5
:Split Rock Creek
Corson 8.5 11.0 14.0 : <5 14 <5 10 <5 <5
:Rock River
Luverne 10.0 12.0 14.0 : <5 18 <5 10 <5 <5
Rock Rapids 13.0 16.0 19.0 : <5 32 <5 18 <5 9
Rock Valley 16.0 17.0 19.0 : <5 18 <5 13 <5 <5
:Big Sioux River
Hawarden 20.5 24.0 27.0 : 17 47 <5 31 <5 18
Akron 16.0 18.0 20.0 : 17 48 <5 42 <5 19
Sioux City 32.0 38.0 41.0 : <5 <5 <5 <5 <5 <5
:James River
Huron 11.5 15.0 19.0 : 38 53 23 41 11 30
Forestburg 12.0 14.5 18.0 : 35 52 26 43 9 29
Mitchell 17.0 21.5 24.0 : 45 58 21 38 12 27
:Firesteel Creek
Mount Vernon 8.0 13.0 15.0 : 59 36 17 21 9 17
:James River
Scotland 13.0 16.0 18.0 : 32 50 24 38 15 29
Yankton 12.0 16.0 21.0 : 27 41 23 37 13 27
:West Fork Vermillion River
Parker 9.0 10.0 12.0 : 5 12 <5 10 <5 <5
:East Fork Vermillion River
Parker 12.0 14.0 16.5 : 23 47 17 39 <5 30
:Vermillion River
Davis 11.0 13.0 15.0 : 24 55 21 41 <5 16
Wakonda 14.0 15.5 17.0 : 24 51 23 50 16 44
Vermillion 21.0 22.0 30.0 : 9 40 8 39 <5 <5
:Redwood River
Marshall 14.0 15.0 16.5 : 10 12 7 8 6 7
:West Fork Des Moines River
Avoca 1425.0 1426.0 1428.0 : 6 13 <5 10 <5 <5
Windom 19.0 21.0 25.0 : <5 11 <5 7 <5 <5
Jackson 12.0 12.5 14.0 : <5 8 <5 6 <5 <5
:Missouri River
South Sioux City 30.0 33.0 36.0 : <5 9 <5 8 <5 6
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: 02/17/2024 - 05/17/2024
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Floyd River
Sheldon 5.9 6.1 6.3 6.8 8.9 10.8 12.6
Alton 6.0 6.1 6.4 6.8 8.3 9.7 13.1
Le Mars 10.1 10.5 11.5 12.5 13.8 15.3 17.6
:West Branch Floyd River
Struble 4.1 4.3 5.3 6.4 7.8 9.8 12.4
:Floyd River
Merrill 0.1 0.4 1.2 2.1 3.3 4.2 8.1
James 8.7 8.9 9.4 10.2 11.2 12.0 16.3
:Little Sioux River
Milford 8.4 8.6 8.8 10.3 13.0 15.9 17.6
Spencer 5.6 5.9 6.7 8.2 10.0 11.6 12.7
:Ocheyedan River
Spencer 3.0 3.1 3.4 4.1 5.4 7.2 8.2
:Little Sioux River
Linn Grove 7.3 7.4 8.1 9.3 12.8 16.0 16.8
Cherokee 9.1 9.4 10.4 11.6 14.7 16.3 17.9
Correctionville 5.4 5.6 6.4 8.0 11.0 12.3 15.5
:West Fork Ditch
Hornick 7.3 7.8 8.6 10.4 11.5 12.6 13.8
:Perry Creek
Sioux City 7.4 7.4 7.5 8.1 8.4 8.7 9.6
:Big Sioux River
Brookings 3.1 3.1 3.5 4.6 7.6 9.7 10.1
Dell Rapids 3.8 3.9 4.5 5.3 8.5 11.4 12.9
Sioux Falls I-90 8.3 8.3 8.3 8.4 10.0 11.6 12.7
:Skunk Creek
Sioux Falls 8.3 8.3 8.3 8.4 10.0 11.6 12.7
:Big Sioux River
Sioux Falls N Cliff 6.5 6.6 7.1 8.1 10.8 14.0 15.8
:Split Rock Creek
Corson 2.1 2.2 2.3 3.0 4.5 7.1 7.7
:Rock River
Luverne 4.3 4.3 4.6 4.9 5.9 7.5 8.2
Rock Rapids 7.5 7.5 7.8 8.4 9.9 11.7 12.3
Rock Valley 5.8 6.1 6.3 7.5 10.4 12.5 12.9
:Big Sioux River
Hawarden 12.5 12.9 13.3 14.3 19.1 21.9 22.7
Akron 6.2 6.4 7.3 8.7 14.8 17.2 17.8
Sioux City 13.0 13.1 13.7 14.8 19.4 21.4 22.1
:James River
Huron 9.8 9.8 9.8 10.6 13.0 19.8 22.1
Forestburg 7.9 7.9 7.9 9.0 14.7 17.6 21.4
Mitchell 12.7 12.7 13.0 15.8 20.9 24.4 25.8
:Firesteel Creek
Mount Vernon 4.4 5.0 5.5 8.8 10.7 14.8 16.6
:James River
Scotland 5.7 5.7 6.0 9.8 15.6 19.5 20.3
Yankton 4.4 4.4 4.7 6.0 14.0 22.8 24.8
:West Fork Vermillion River
Parker 1.3 1.3 1.5 2.1 3.4 7.1 8.8
:East Fork Vermillion River
Parker 5.6 5.7 6.1 6.9 9.4 14.3 15.7
:Vermillion River
Davis 3.1 3.3 4.4 5.7 9.3 14.0 14.6
Wakonda 4.0 4.3 5.1 6.4 12.2 17.3 17.6
Vermillion 2.7 2.9 4.5 5.9 12.9 19.9 26.0
:Redwood River
Marshall 7.5 8.2 8.8 10.0 12.0 14.1 16.7
:West Fork Des Moines River
Avoca 1419.1 1419.2 1419.6 1420.0 1422.2 1424.4 1425.1
Windom 11.1 11.3 11.5 12.6 15.9 17.6 18.0
Jackson 8.0 8.1 8.4 8.8 10.0 10.8 11.0
:Missouri River
South Sioux City 11.0 11.2 11.5 13.7 16.6 22.4 28.3
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: 02/17/2024 - 05/17/2024
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Floyd River
Sheldon 4.2 4.1 4.1 4.1 4.1 4.1 4.1
Alton 5.3 5.3 5.3 5.2 5.1 5.0 5.0
Le Mars 8.5 8.4 8.4 7.8 7.5 7.4 7.3
:West Branch Floyd River
Struble 3.6 3.6 3.5 3.4 3.4 3.3 3.3
:Floyd River
Merrill 0.0 0.0 0.0 0.0 0.0 0.0 0.0
James 8.2 8.2 8.2 8.0 7.9 7.8 7.8
:Little Sioux River
Milford 7.7 7.7 7.4 7.2 6.5 6.2 6.2
Spencer 4.8 4.8 4.4 4.1 3.7 3.5 3.5
:Ocheyedan River
Spencer 2.6 2.6 2.5 2.3 2.2 2.1 2.1
:Little Sioux River
Linn Grove 7.0 6.9 6.6 6.2 5.7 5.2 5.1
Cherokee 8.5 8.5 8.4 8.2 8.1 7.2 7.1
Correctionville 5.0 5.0 4.9 4.7 4.6 4.5 4.4
:West Fork Ditch
Hornick 5.9 5.9 5.9 5.7 5.5 5.4 5.4
:Perry Creek
Sioux City 6.9 6.8 6.6 6.3 6.1 6.0 5.8
:Big Sioux River
Brookings 3.0 3.0 2.8 2.5 2.1 2.0 1.9
Dell Rapids 3.7 3.7 3.6 3.3 2.8 2.4 2.4
Sioux Falls I-90 5.5 5.3 5.1 4.7 3.9 3.4 3.3
:Skunk Creek
Sioux Falls 5.5 5.3 5.1 4.7 3.9 3.4 3.3
:Big Sioux River
Sioux Falls N Cliff 6.1 6.1 6.1 6.0 5.7 5.4 5.3
:Split Rock Creek
Corson 2.0 2.0 2.0 1.8 1.6 1.4 1.4
:Rock River
Luverne 4.2 4.2 4.2 4.2 4.2 4.2 4.2
Rock Rapids 7.0 7.0 7.0 6.6 6.3 6.3 6.3
Rock Valley 5.1 5.1 5.0 4.9 4.7 4.6 4.6
:Big Sioux River
Hawarden 12.0 12.0 11.8 11.6 11.2 10.9 10.5
Akron 5.5 5.5 5.2 5.0 4.6 4.3 3.7
Sioux City 12.5 12.5 12.2 12.0 11.6 11.4 11.0
:James River
Huron 9.5 9.5 9.5 9.3 9.2 9.2 9.2
Forestburg 6.8 6.3 5.6 4.9 4.7 4.5 4.5
Mitchell 12.3 12.3 11.9 11.0 10.8 10.5 10.5
:Firesteel Creek
Mount Vernon 2.7 2.6 2.6 2.6 2.5 2.5 2.4
:James River
Scotland 5.5 5.5 5.3 4.9 4.7 4.6 4.6
Yankton 4.2 4.2 4.2 4.0 3.8 3.6 3.6
:West Fork Vermillion River
Parker 1.1 1.1 1.1 0.8 0.4 0.3 0.3
:East Fork Vermillion River
Parker 5.5 5.5 5.4 5.1 4.6 4.2 3.9
:Vermillion River
Davis 2.7 2.7 2.7 2.4 2.3 2.3 2.3
Wakonda 3.7 3.6 3.6 3.1 2.0 1.7 1.5
Vermillion 2.2 2.2 2.1 1.8 1.5 1.4 1.3
:Redwood River
Marshall 7.1 7.0 6.9 6.8 6.7 6.6 6.6
:West Fork Des Moines River
Avoca 1418.6 1418.6 1418.5 1418.5 1418.4 1418.3 1418.2
Windom 10.4 10.3 10.2 10.2 10.1 10.0 9.8
Jackson 7.5 7.5 7.4 7.3 7.3 7.2 7.1
:Missouri River
South Sioux City 6.5 6.5 6.5 6.2 5.9 5.5 4.4
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/fsd for more weather and water
information.
The next outlook will be issued on February 29th, 2024.
$$
Kalin