Flood Potential Outlook
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
548
FGUS73 KBIS 261721
ESFBIS
NDC001-007-011-015-021-025-029-031-033-037-041-043-045-047-051-053-
055-057-059-061-065-083-085-087-089-093-103-105-270130-
Probabilistic Hydrologic Outlook
National Weather Service Bismarck ND
1221 PM CDT Thu Mar 26 2026
...FLOOD AND WATER RESOURCES OUTLOOK...
This Flood and Water Resources Outlook is for the Missouri and James
River basins of North Dakota, covering the period of March 29th
through June 27th, 2026.
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...
The overall probability of widespread flooding across the Missouri
and and James River basins is seasonably low for this outlook
period. This is a result of the lack of snowcover as of late March,
and the continued thawing of soils. Earlier-season snowfall and
recent light snow events have produced some runoff that has already
made its way through creeks and streams with little fanfare outside
of early-season, within-bank rises. Ice is now out of many creeks and
rivers, and will continue to thaw and break up in others, along with
area lakes and reservoirs in the coming weeks. This means the risk of
ice-jam related flooding has also diminished.
Despite the lack of snowcover, soils are wet across much of the
James and Missouri River basins, outside of far southwest North
Dakota. As a result, if a heavy snow or heavy rain event was to
occur, it could generate enough runoff to cause increased flows on
creeks and streams. That scenario accounts for the low probability
of flooding that exists in the flood outlook probabilities. The
outlook already accounts for both current soil moisture conditions
and the historical frequency of springtime rain and snow events, and
generally reflects an overall below-normal risk of flooding due the
lack of snowcover and thawing soils.
...Snowpack Conditions...
Snowcover is not present in either the Missouri or James River
basins in North Dakota as of late March. Earlier-season snowpack
melted with stretches of warm weather after the 1st of the year, and
either ran off into local streams or infiltrated soils. The result
has been wet soils in many portions of the Missouri and James River
basins.
As is always the case this time of the year, additional snowfall may
still occur, which could result in short-term snowmelt runoff yet
this spring. The probabilities in this flood outlook already account
for the historical frequency and probability of those potential snow
events.
...Current Drought Conditions...
There are no current drought designations in the Missouri and James
River basins of North Dakota.
...Reservoirs and Natural Wetlands...
Natural wetlands and artificial reservoirs are generally within the
long-term normal range for this time of the year. Flood control
features are generally at their normal spring draw-down levels.
This suggests that local water storage will provide a normal amount
of flood mitigation this spring.
...Soil Conditions...
Soils have been warming through the last few weeks, though a stretch
of colder weather in mid March slowed the progression of thawing in
parts of the area. The southwest corner of North Dakota has had the
warmest weather, and frost has gone out there with soil temperatures
above freezing throughout the entire top 40 inches of the soil
profile. Across northwest and central North Dakota into the James
River Valley, there is more variability with regard to how deep the
above-freezing layer has progressed into the soils, ranging from as
little as 8 inches to as much as 20 inches. However, this is within
the normal range for this time of the year, and the soils are
expected to continue thawing going into early April.
Soils across much of the Missouri and James River basins in North
Dakota remain very wet. This is the result of early-winter snowfall
on warm soils that caused considerable melting, and also the melting
of that snowpack and additional light precipitation events the last
few months. The exception to the wet soils is in the very southwest
part of the state, where above normal temperatures have continued to
dry out the soils in recent weeks.
...Weather Outlook...
The short term weather forecast calls for warm and mainly dry
weather to close out the month of March, but the 6-10 and 8-14 day
outlooks favor above normal precipitation probabilities for North
Dakota in early April. The overall weather pattern will begin to
favor cooler temperatures, as well, especially in northern parts of
the state in the 6-10 and 8-14 day period. Looking further out, when
considering the outlook for the full month of April, there are equal
chances of above-normal, near-normal, or below-normal temperatures
and precipitation. This ultimately suggests that a relatively normal
spring weather pattern featuring large variability is highly
probable. That includes the aforementioned potential for a wetter
and cooler start to April.
Looking even longer term, the 3-month outlook covering April, May,
and June has almost all of the Missouri and James River basins in
equal chances for above-normal, near-normal, or below-normal
temperatures and precipitation. The exception is the southwestern
corner of North Dakota, which favors above-normal temperatures in
that 3-month period. This is consistent with historical trends for
the area as a La Nina pattern fades through the spring.
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: 3/29/2026 - 6/27/2026
: 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
-------- ----- ----- ----- : --- --- --- --- --- ---
: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 16 <5 13 <5 9
LaMoure 14.0 16.0 18.0 : <5 17 <5 8 <5 <5
:Missouri River
Williston 22.0 24.0 26.0 : 6 42 <5 31 <5 9
: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 : 11 52 <5 <5 <5 <5
:Beaver Creek
Linton 12.0 14.0 16.0 : 5 44 <5 31 <5 13
:Little Muddy River
Williston 10.0 12.0 14.0 : 13 69 <5 27 <5 7
:Little Missouri River
Marmarth 18.0 23.0 30.0 : <5 6 <5 <5 <5 <5
Medora 15.0 18.0 20.0 : 5 21 <5 8 <5 6
Watford City 20.0 24.0 30.0 : <5 11 <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 : 8 22 5 11 <5 8
:Knife River
Hazen 21.0 24.0 25.0 : 6 37 <5 28 <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 : 20 61 17 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: 3/29/2026 - 6/27/2026
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Pipestem
Pingree 7.5 7.5 7.5 7.5 7.8 8.3 9.2
:James River
Grace City 5.2 5.2 5.2 5.3 6.6 7.5 8.2
LaMoure 8.2 8.2 8.2 8.2 8.9 10.0 12.4
:Missouri River
Williston 16.8 17.3 17.4 17.7 18.8 21.0 22.4
:Cannonball River
Regent 5.3 5.3 5.9 6.8 7.6 8.5 9.2
:Cedar Creek
Raleigh 1.1 1.2 2.3 3.7 5.0 6.2 6.7
:Cannonball River
Breien 2.7 2.8 4.7 6.2 8.1 10.1 10.6
:Beaver Creek
Linton 4.7 4.7 4.9 5.5 6.8 10.5 12.0
:Little Muddy River
Williston 4.6 4.6 4.6 7.8 9.3 10.1 11.7
:Little Missouri River
Marmarth 0.7 0.7 0.7 2.5 8.0 11.1 14.2
Medora 2.4 2.4 2.6 4.0 8.8 11.9 14.9
Watford City 8.2 8.2 8.8 10.3 13.3 15.3 18.4
:Knife River
Manning 6.1 6.1 7.1 8.2 8.9 11.8 12.8
:Spring Creek
Zap 4.8 4.8 6.1 7.8 9.4 11.3 18.7
:Knife River
Hazen 2.0 2.0 4.5 7.1 11.4 17.1 22.7
:Heart River
Mandan 11.7 12.0 12.9 15.1 18.3 20.9 24.1
:Apple Creek
Menoken 6.2 6.2 6.9 12.4 14.5 16.5 16.7
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: 3/29/2026 - 6/27/2026
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Pipestem
Pingree 6.8 6.7 6.7 6.7 6.7 6.7 6.7
:James River
Grace City 4.4 4.3 4.3 4.3 4.3 4.3 4.3
LaMoure 7.8 7.8 7.7 7.7 7.7 7.7 7.7
:Missouri River
:Cannonball River
Regent 5.2 5.2 5.2 5.2 5.2 5.2 5.2
:Cedar Creek
Raleigh 0.4 0.4 0.4 0.4 0.4 0.4 0.4
:Cannonball River
Breien 2.3 2.2 2.2 2.1 2.1 2.1 2.0
:Beaver Creek
Linton 4.4 4.4 4.4 4.4 4.3 4.3 4.3
:Little Muddy River
Williston 4.5 4.5 4.5 4.5 4.4 4.4 4.4
:Little Missouri River
Marmarth 0.7 0.7 0.7 0.7 0.7 0.7 0.7
Medora 2.3 2.3 2.3 2.3 2.3 2.3 2.2
Watford City 8.2 8.2 8.2 8.1 8.1 8.1 8.1
:Knife River
Manning 6.1 6.1 6.1 6.1 6.0 6.0 6.0
:Spring Creek
Zap 4.7 4.7 4.7 4.7 4.7 4.7 4.7
:Knife River
Hazen 2.0 2.0 2.0 1.9 1.9 1.9 1.9
:Heart River
Mandan 11.4 11.3 11.2 10.9 10.8 10.8 10.8
:Apple Creek
Menoken 4.2 4.2 4.0 3.8 3.4 3.3 3.3
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 April.
$$
CJS