Flood Potential Outlook
Issued by NWS Rapid City, SD
Issued by NWS Rapid City, SD
Versions:
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FGUS73 KUNR 131617
ESFUNR
SDC007-019-033-047-055-063-071-081-093-095-102-103-105-121-123-137-
WYC005-011-045-250000
Probabilistic Hydrologic Outlook
National Weather Service Rapid City SD
917 AM MST Thu Feb 13 2025
...Spring Flood and Water Resource Outlook...
...Below-Average Flood Potential This Spring...
This spring flood and water resource outlook is for the Rapid City
Hydrologic Service Area (HSA), which covers northeastern Wyoming and
western South Dakota. The main river basins include the Little
Missouri, eastern Powder, Belle Fourche, Grand, Moreau, Cheyenne,
Bad, White, and Keya Paha.
.Flood Outlook Summary...
The flood potential this spring is below average across all of
northeastern Wyoming and western South Dakota.
.Snow Cover and Liquid Water Content...
Snow depth is from a trace to 2 inches across much of the area.
However, snow depths of 4 to 8 inches are found across parts of
far northwestern South Dakota and northeastern Wyoming. In the Black
Hills, snow depths range from a few inches in the southern Hills to
around 2 feet in parts of the northern Hills. The liquid water
content on the plains is relatively low.
.Soil Conditions and Frost Depths...
Soil moisture is below average across all of the area and frost
depths are generally from 1 to 3 feet.
.Lake and River Conditions...
Ice thickness on rivers, streams, and lakes ranges is generally
above average given the recent cold weather and limited snow
cover. Continued cold weather for at least another week will
maintain the ice cover.
.Weather Outlooks...
The precipitation outlook for spring through summer favors drier
than average conditions. The temperature outlook for spring through
summer favors near- to above-average temperatures. These outloooks
are consistent with the decay of La Nia followed by near-average
eastern Pacific Ocean temperatures.
.Numerical River 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: 2/15/2025 - 9/30/2025
: 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
-------- ----- ----- ----- : --- --- --- --- --- ---
:Little Missouri River
Camp Crook 12.0 17.0 19.0 : 16 44 <5 20 <5 6
:Moreau River
Faith 16.0 18.0 21.0 : <5 21 <5 12 <5 6
:Belle Fourche River
WY-SD State Line 15.0 16.0 18.0 : <5 16 <5 <5 <5 <5
:South Belle Fourche River
Sturgis 15.0 17.0 19.0 : 22 26 17 18 8 9
:Belle Fourche River
Elm Springs 19.0 22.0 24.0 : 10 16 <5 <5 <5 <5
:Cheyenne River
Wasta 13.0 15.0 16.0 : <5 7 <5 <5 <5 <5
Plainview 17.0 19.0 20.0 : 27 48 18 27 13 17
:Bad River
Midland 21.0 24.0 25.0 : 21 39 <5 5 <5 <5
:White River
Kadoka 15.0 16.0 19.0 : 38 53 23 45 7 19
White River 14.0 15.0 17.0 : 29 48 22 39 16 25
Oacoma 15.0 20.0 25.0 : 58 75 9 24 <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: 2/15/2025 - 9/30/2025
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Little Missouri River
Camp Crook 2.5 2.8 3.3 5.6 7.4 14.8 15.8
:Moreau River
Faith 2.8 3.6 4.8 6.2 9.7 11.4 12.2
:Belle Fourche River
WY-SD State Line 4.4 4.5 5.5 7.2 10.6 13.4 14.5
:South Belle Fourche River
Sturgis 4.5 5.3 6.1 8.2 13.6 17.6 19.8
:Belle Fourche River
Elm Springs 5.8 6.4 7.6 9.4 15.0 18.9 20.9
:Cheyenne River
Wasta 0.5 0.8 1.8 3.6 5.2 6.3 8.3
Plainview 9.7 10.0 11.0 13.6 18.0 20.5 21.5
:Bad River
Midland 4.5 5.4 6.9 15.3 20.1 22.6 23.1
:White River
Kadoka 7.6 7.9 10.2 14.3 15.9 17.8 25.4
White River 7.3 8.0 10.8 12.8 14.3 17.6 23.9
Oacoma 10.8 11.4 14.0 15.8 17.9 19.3 22.9
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: 2/15/2025 - 9/30/2025
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Little Missouri River
Camp Crook 2.0 2.0 2.0 1.8 1.7 1.5 1.4
:Moreau River
Faith 1.5 1.5 1.4 1.4 1.4 1.4 1.4
:Belle Fourche River
WY-SD State Line 3.3 3.3 3.3 3.2 3.2 3.2 3.1
:South Belle Fourche River
Sturgis 2.2 2.2 2.2 2.2 2.2 2.2 2.2
:Belle Fourche River
Elm Springs 3.9 3.9 3.9 3.9 3.8 3.8 3.8
:Cheyenne River
Wasta 0.3 0.2 0.2 0.2 0.1 0.1 0.1
Plainview 8.4 8.3 8.3 8.3 8.3 8.3 8.2
:Bad River
Midland 2.6 2.6 2.6 2.6 2.6 2.6 2.6
:White River
Kadoka 4.2 4.1 4.0 3.7 3.6 3.6 3.6
White River 3.5 3.5 3.4 3.1 3.0 3.0 3.0
Oacoma 7.5 7.5 7.5 7.0 6.7 6.5 6.5
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/unr for more weather and water
information.
.Outlook Schedule...
The next outlook will be issued February 27, 2025.
$$
Bunkers