Flood Potential Outlook
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
896
FGUS73 KBIS 131820
ESFBIS
NDC001-007-011-015-021-025-029-031-033-037-041-043-045-047-051-053-
055-057-059-061-065-083-085-087-089-093-103-105-161700-
Probabilistic Hydrologic Outlook
National Weather Service Bismarck ND
1220 PM CST Thu Feb 13 2025
...SPRING FLOOD AND WATER RESOURCES OUTLOOK...
This Spring Flood and Water Resources Outlook is for the Missouri
and James River basins of North Dakota, covering the period of 15
February,2025 through 16 May, 2025. This is the first in a series of
three Spring Flood Outlooks covering flood probabilities for NWS
forecast locations. The next outlook will be issued on February
27th. Below is the full schedule for this series of outlooks.
First edition - Thursday, February 13th, 2025.
Second edition - Thursday, February 27th, 2025.
Third edition - Thursday, March 13th, 2025.
After the above Spring Flood and Water Resources Outlooks, the NWS
expects to revert back to its normally scheduled monthly release of
Flood and Water Resources Outlooks on, or about, 27 March, 2025.
The following message has four sections. The first provides some
text on the highlights of this outlook and conditions affecting the
local hydrology. The second section gives the current and historical
risks of flooding as determined by the Ensemble Streamflow Forecast
model of the National Weather Service. The third section gives the
current probabilities for reaching flood stage at the listed
forecast locations. And finally, the fourth section covers the risk
of the river sites falling below the listed stages.
...Flood Outlook Highlights...
There are really only three locations near historically normal risk
levels of flooding at this point in time. These three are all in the
James River Basin and include the Pipestem Creek near Pingree, James
River at Grace City, and the James River at LaMoure. Other than
these three locations that are at near normal risks of flooding, all
other locations are below to well-below normal risks of flooding in
the Missouri and James River basins of North Dakota.
In short, the Snow-Water Equivalent (SWE) contained in the existing
snowpack is not only below normal in most areas, but the modest
amount of water contained in the snowpack is sitting on dry to
very-dry soils. Under all but the more extreme melt conditions,
those dry soils are expected to substantially reduce runoff from
melting snow and early spring rains.
...Snowpack Conditions...
The Snow-water Equivalent (SWE) trends have placed the higher SWE
values in the upper James and Pipestem Creek watersheds. Up to two
inches of SWE are available in portions of those watersheds and
provides the basis for near normal risk levels of flooding if that
area continues to receive above normal levels of snow going forward
into spring.
Another area with up to two inches of SWE is Williams County. In
particular, western and eastern Williams County have over two inches
of SWE and may enhance runoff into the small streams in that area,
including the White Earth River.
Outside of the area listed above, most of the remaining portions of
the James and Missouri River basins of North Dakota contain less
than an inch of SWE with values of around two inches found in small,
localized areas.
...Current Drought Conditions...
Drought remains a concern across much of North Dakota with a large
pocket of D3 (Extreme) drought centered on McKenzie and northwest
Dunn counties. D1 and D2 levels of drought cover most of the areas
west of the Missouri River and south of I-95 east of Highway 83.
North and east of these areas, drought designations rapidly diminish
and are near normal.
...Reservoirs and Natural Wetlands...
Streamflow tends to be well below normal to the lower range of
normal for this time of year on most streams and rivers. Wetlands
in the Prairie Pothole Region continue to generally be above
long-term water levels, but are also generally below their highs of
last summer.
...Soil Conditions...
Soil moisture values remain well below normal across much of western
and south central North Dakota. These dry soils are expected to
reduce runoff and produce less streamflow than expected from a given
SWE and early spring rains.
...Weather Outlook...
The near term 6-10 day weather outlooks favor a continuation of
below normal temperatures and below normal precipitation. In the
slightly longer 8-14 day outlooks, the region is favored to warm up
to near normal to slightly above normal temperatures, but remains
favored for below normal precipitation. For the full month of
February, expectations are that it will have an overall below normal
temperature outcome with equal chances for an above normal, near
normal, or below normal amount of moisture.
Looking even longer term at the three-month outlooks (Feb-Apr),
there is a strong favoring for below normal temperatures with an
equal chances designation for above normal, near normal, or below
normal precipitation.
...Ice Conditions...
Smaller streams and rivers are iced over at this point and should
remain that way until the spring melt season. Ice on reservoirs and
lakes is generally of near-normal thickness for this time of year.
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: 02/15/2025 - 05/16/2025
: 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
-------- ----- ----- ----- : --- --- --- --- --- ---
:Pipestem
Pingree 11.0 13.0 15.0 : 16 12 <5 <5 <5 <5
:James River
Grace City 12.0 14.0 15.0 : 8 15 5 9 <5 8
LaMoure 14.0 16.0 18.0 : 16 17 6 8 <5 <5
:Missouri River
Williston 22.0 24.0 26.0 : <5 20 <5 8 <5 5
:Cannonball River
Regent 22.0 24.0 26.0 : <5 <5 <5 <5 <5 <5
:Cedar Creek
Raleigh 12.0 14.0 16.0 : <5 9 <5 5 <5 <5
:Cannonball River
Breien 10.0 20.0 23.0 : 16 55 <5 <5 <5 <5
:Beaver Creek
Linton 12.0 14.0 16.0 : 20 41 7 28 <5 13
:Little Muddy River
Williston 10.0 12.0 14.0 : 5 60 <5 32 <5 10
:Little Missouri River
Marmarth 18.0 23.0 30.0 : <5 <5 <5 <5 <5 <5
Medora 15.0 18.0 20.0 : <5 15 <5 8 <5 <5
Watford City 20.0 24.0 30.0 : <5 13 <5 <5 <5 <5
:Knife River
Manning 15.0 17.0 20.0 : <5 20 <5 <5 <5 <5
:Spring Creek
Zap 14.0 18.0 20.0 : <5 22 <5 14 <5 8
:Knife River
Hazen 21.0 24.0 25.0 : <5 40 <5 25 <5 20
:Heart River
Mandan 27.0 33.0 38.0 : <5 17 <5 <5 <5 <5
:Apple Creek
Menoken 15.0 16.0 17.0 : 29 55 16 52 <5 31
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: 02/15/2025 - 05/16/2025
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Pipestem
Pingree 5.5 5.5 5.5 6.8 10.7 11.6 12.1
:James River
Grace City 4.3 4.3 4.4 5.4 10.2 11.4 14.2
LaMoure 7.0 7.0 7.1 7.8 11.6 15.5 16.4
:Missouri River
Williston 15.5 15.6 15.9 16.2 17.6 18.5 20.9
:Cannonball River
Regent 5.2 5.9 6.2 7.1 8.0 9.5 12.5
:Cedar Creek
Raleigh 1.7 2.7 3.2 4.0 5.4 6.0 7.1
:Cannonball River
Breien 3.3 4.3 5.5 7.0 8.5 11.3 12.2
:Beaver Creek
Linton 4.9 5.1 5.6 6.5 10.5 12.7 14.6
:Little Muddy River
Williston 4.6 4.6 5.0 5.6 6.9 8.1 10.0
:Little Missouri River
Marmarth 1.1 1.4 1.8 2.6 4.9 7.5 8.4
Medora 1.4 1.9 2.6 3.3 5.5 8.0 9.0
Watford City 7.1 7.6 8.3 9.1 10.6 12.9 13.5
:Knife River
Manning 6.1 6.1 6.1 6.6 7.7 8.6 9.5
:Spring Creek
Zap 4.7 4.7 4.7 5.2 6.1 6.4 7.6
:Knife River
Hazen 0.4 0.7 1.2 3.0 4.4 7.4 8.0
:Heart River
Mandan 10.1 10.8 11.3 12.8 16.7 20.3 22.4
:Apple Creek
Menoken 5.2 5.3 5.5 8.4 15.3 16.0 16.2
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: 02/15/2025 - 05/16/2025
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Pipestem
Pingree 5.5 5.5 5.5 5.5 5.5 5.5 5.5
:James River
Grace City 4.3 4.3 4.3 4.3 4.2 4.2 4.2
LaMoure 7.0 7.0 7.0 7.0 7.0 7.0 7.0
:Missouri River
:Cannonball River
Regent 4.7 4.7 4.7 4.7 4.7 4.7 4.7
:Cedar Creek
Raleigh 0.1 0.1 0.1 0.1 0.1 0.0 0.0
:Cannonball River
Breien 1.9 1.9 1.9 1.9 1.9 1.8 1.8
:Beaver Creek
Linton 4.4 4.4 4.4 4.4 4.4 4.3 4.3
:Little Muddy River
Williston 4.4 4.4 4.4 4.4 4.4 4.4 4.4
:Little Missouri River
Marmarth 1.1 1.1 1.1 1.1 1.0 1.0 0.9
Medora 1.3 1.3 1.3 1.3 1.3 1.2 1.2
Watford City 7.0 7.0 7.0 7.0 7.0 6.9 6.8
:Knife River
Manning 6.1 6.1 6.1 6.1 6.0 6.0 6.0
:Spring Creek
Zap 4.6 4.6 4.6 4.6 4.6 4.6 4.6
:Knife River
Hazen 0.4 0.4 0.3 0.3 0.3 0.2 0.2
:Heart River
Mandan 9.1 9.1 9.1 9.1 9.0 8.9 8.9
:Apple Creek
Menoken 4.1 4.1 4.0 4.0 4.0 3.7 3.7
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/bis for more weather and water
information.
The next outlook will be issued by the end of March.
$$
Schlag