Probabilistic Hydrologic Outlook
National Weather Service Bismarck ND
1134 AM CDT Thu Mar 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
March, 2025 through 13 June, 2025. This is the third and final
edition of the Spring Flood and Water Resources Outlook series
covering flood probabilities for NWS forecast locations. The NWS
will revert back to our regular schedule for updating these flood
probabilities on March 27th.
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...
After recent warm weather, all forecast locations in the Missouri
and James River basins are now below historically normal risk levels
of flooding. In short, with very little snow on the ground and only
a few weeks left in the traditional snow accumulation season
provides little opportunity to build much in the way of a
threatening snowpack. Along with a lack of Snow-Water Equivalent,
significant warming of the ground in many areas will allow future
precipitation an opportunity to infiltrate into abnormally dry
soils. All this suggests that the modest probabilities presented
below are due to severe thunderstorms present in the historical data
used in the models.
Importantly, there is a fairly significant storm likely to hit the
eastern part of North Dakota March 14-15, that event will not
materially affect the below probabilities or narrative.
...Snowpack Conditions...
Very little snow remains in the Missouri and James River basins of
North Dakota. What snow remains is largely confined to sheltered
areas and drifts that tend to melt slowly and produce little in the
way of runoff.
...The Missouri and Yellowstone rivers west of Williston...
The initial rush of runoff from the snowpack on the plains of
eastern Montana was insufficient to fully remove the ice on the
Yellowstone and Missouri rivers west of Williston. While some ice
remains, it is no longer of sufficient quantity to present much risk
in the form of ice jams. This suggests the next opportunity for
high water in this area will be when the mountain snowpack melts,
and even this risk is below normal this year as the mountain
snowpack is about 90 percent of normal.
...The Little Missouri River...
The Little Missouri River has already melted off the vast majority
of its snowpack and ice cover. This suggests any future risk of high
water will largely be due to thunderstorms during the summer severe
weather season.
...Current Drought Conditions...
No significant changes have occurred with respect to drought
designations over the past month. However, 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...
Due to the early melt of a very uneven, but generally below normal
snowpack this year, the net results vary wildly. Some areas have
seen enough runoff to fill the smaller natural and man-made water
features, but overall runoff has been lacking. This is a cause for
concern on smaller water supply features.
...Soil Conditions...
Soil moisture values remain well below normal across much of western
and south central North Dakota. These dry soils continue to warm and
many areas now have little to no frost in the ground. These warm and
dry soils will minimize runoff from future precipitation, regardless
if it comes as rain or snow.
...Weather Outlook...
The near term 6-10 day weather outlooks favors near normal
temperatures and below normal precipitation in the northeastern half
of the state, and above normal temperatures with near normal
precipitation in the southwestern half of the state. The 8-14 day
outlooks favor above normal temperatures and near normal
precipitation across all of North Dakota. Looking a little farther
into the future, the latter part of March and very early April are
favored to see above normal temperatures with an equal chance of
above normal, near normal, or below normal precipitation. Looking
even longer into the future at the 3-month outlook for March, April
and May, the western one-third of North Dakota is slightly favored
for below normal temperatures with the remainder of the state with
an equal chances designation for above normal, near normal, or below
normal temperatures. During the same time period, the entire state
has the equal chances designation for above normal, near normal, or
below normal precipitation.
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: 03/15/2025 - 06/13/2025
: 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 : <5 12 <5 <5 <5 <5
:James River
Grace City 12.0 14.0 15.0 : <5 15 <5 9 <5 8
LaMoure 14.0 16.0 18.0 : 7 17 <5 8 <5 <5
:Missouri River
Williston 22.0 24.0 26.0 : 6 42 <5 25 <5 8
: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 : 14 58 <5 <5 <5 <5
:Beaver Creek
Linton 12.0 14.0 16.0 : 14 45 <5 31 <5 13
:Little Muddy River
Williston 10.0 12.0 14.0 : 21 73 7 42 <5 10
:Little Missouri River
Marmarth 18.0 23.0 30.0 : <5 6 <5 <5 <5 <5
Medora 15.0 18.0 20.0 : 5 24 <5 8 <5 6
Watford City 20.0 24.0 30.0 : <5 14 <5 5 <5 <5
:Knife River
Manning 15.0 17.0 20.0 : 11 26 <5 <5 <5 <5
:Spring Creek
Zap 14.0 18.0 20.0 : 8 31 6 17 5 8
:Knife River
Hazen 21.0 24.0 25.0 : 6 43 <5 31 <5 26
:Heart River
Mandan 27.0 33.0 38.0 : <5 17 <5 <5 <5 <5
:Apple Creek
Menoken 15.0 16.0 17.0 : 16 58 7 55 <5 34
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: 03/15/2025 - 06/13/2025
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Pipestem
Pingree 5.5 5.5 5.5 5.6 6.6 10.1 10.4
:James River
Grace City 4.3 4.3 4.3 4.6 6.0 8.0 9.1
LaMoure 7.3 7.3 7.3 7.8 8.8 10.2 15.2
:Missouri River
Williston 16.3 17.1 17.4 17.8 19.0 20.7 22.2
:Cannonball River
Regent 5.2 5.3 6.1 7.0 8.3 9.4 9.5
:Cedar Creek
Raleigh 0.5 1.2 2.6 3.9 4.9 5.9 6.2
:Cannonball River
Breien 2.3 3.0 4.3 6.3 8.4 10.6 10.8
:Beaver Creek
Linton 4.5 4.5 6.4 8.5 10.3 12.3 13.5
:Little Muddy River
Williston 5.6 5.6 6.2 8.5 9.6 10.7 12.2
:Little Missouri River
Marmarth 1.4 1.4 1.8 4.1 8.6 11.6 14.9
Medora 3.0 3.0 3.2 4.7 9.2 12.2 15.7
Watford City 8.5 8.5 8.9 10.2 12.0 15.0 18.4
:Knife River
Manning 6.7 6.7 7.3 8.8 10.0 15.1 15.2
:Spring Creek
Zap 4.8 4.8 5.0 6.5 8.9 11.5 19.3
:Knife River
Hazen 1.1 1.3 2.7 5.5 10.0 18.5 23.1
:Heart River
Mandan 9.8 10.2 11.2 13.1 17.3 21.4 23.4
:Apple Creek
Menoken 4.6 4.7 5.3 6.9 11.2 16.0 16.1
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: 03/15/2025 - 06/13/2025
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 4.2 4.2 4.2 4.2
LaMoure 7.2 7.1 7.0 7.0 7.0 7.0 7.0
:Missouri River
:Cannonball River
Regent 4.8 4.8 4.7 4.7 4.7 4.7 4.7
:Cedar Creek
Raleigh 0.1 0.1 0.0 0.0 0.0 0.0 0.0
:Cannonball River
Breien 1.9 1.9 1.9 1.9 1.8 1.8 1.8
:Beaver Creek
Linton 4.3 4.3 4.3 4.3 4.2 4.2 4.2
:Little Muddy River
Williston 4.6 4.6 4.5 4.5 4.5 4.5 4.4
:Little Missouri River
Marmarth 1.2 1.2 1.1 1.1 1.0 0.9 0.8
Medora 2.8 2.8 2.8 2.7 2.7 2.7 2.7
Watford City 8.2 8.2 8.1 8.1 8.1 8.0 8.0
:Knife River
Manning 6.5 6.4 6.4 6.3 6.2 6.2 6.2
:Spring Creek
Zap 4.8 4.7 4.7 4.7 4.7 4.7 4.7
:Knife River
Hazen 0.9 0.9 0.8 0.7 0.6 0.6 0.5
:Heart River
Mandan 9.3 9.3 9.2 9.1 9.0 9.0 8.9
:Apple Creek
Menoken 4.3 4.3 4.1 3.8 3.5 3.4 3.4
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/bis for more weather and water
information.
The next outlook will be issued on March 27th, 2025.
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