694
FGUS73 KBIS 261847
ESFBIS
NDC001-007-011-015-021-025-029-031-033-037-041-043-045-047-051-053-
055-057-059-061-065-083-085-087-089-093-103-105-270300-
PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE BISMARCK ND
1247 PM CST THU FEB 26 2026
..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 01
MARCH THROUGH 30 MAY, 2026. THIS OUTLOOK IS THE SECOND OF THREE IN
A SERIES OF OUTLOOKS THAT THE NATIONAL WEATHER SERVICE COLLECTIVELY
REFERS TO AS THE SPRING FLOOD AND WATER RESOURCES OUTLOOKS. THIS
WILL BE FOLLOWED BY THE FINAL SPRING FLOOD AND WATER RESOURCES
OUTLOOK TO BE ISSUED ON 12 MARCH, 2026. ON MARCH 26TH, THE NATIONAL
WEATHER SERVICE WILL REVERT BACK TO ITS NORMAL ISSUANCE OF THE
90-DAY PROBABILISTIC OUTLOOKS, USUALLY ON, OR ABOUT THE 4TH THURSDAY
OF EVERY MONTH.
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
IN GENERAL, THE MODELS DO NOT CURRENTLY REFLECT MUCH RISK OF
WIDESPREAD FLOODING ACROSS THE JAMES AND MISSOURI RIVER BASIN
FORECAST LOCATIONS. THIS IS LARGELY DUE TO THE LOSS OF MOST OF THE
SNOW RECEIVED EARLY THIS WINTER DURING LENGTHY WARM PERIODS OF TIME
WHERE THE SNOW MELTED AND EITHER RAN OFF INTO THE LOCAL STREAMS, OR
INFILTRATED INTO THE GROUND SURFACE. THE DOWNSIDE TO THIS EARLY LOSS
OF THE SNOWPACK WAS THAT THE GROUND IS NOW NEARLY IMPERMEABLE TO
FURTHER INFILTRATION OF RAINFALL AND RUNOFF GENERATED BY MELTING
SNOW.
THIS NEARLY IMPERMEABLE SURFACE OF THE GROUND IS WHAT CREATES THE
CURRENT FLOOD RISK. GIVEN THE TIME OF YEAR, IT IS HIGHLY LIKELY THAT
THE AREA WILL AGAIN RECEIVE MORE SNOW, EVEN THOUGH IT WOULD BE
UNLIKELY TO ENTER THE SPRING MELT SEASON WITH AN EXCEPTIONAL
SNOWPACK. HOWEVER, THE REGION IS ALSO NOW ENTERING THE TIME OF YEAR
WHERE AN EARLY SPRING RAIN COULD FALL ON THIS NEAR IMPERMEABLE
SURFACE AND CREATE A SURPRISING AMOUNT OF RUNOFF. SO, WHILE THE
SNOWPACK IS CURRENTLY INSUFFICIENT TO GENERATE MUCH CONCERN...THERE
REMAINS A DISTINCTLY NON-ZERO RISK OF FLOODING, ESPECIALLY IF THE
REGION WERE TO EXPERIENCE A WARM COLORADO LOW BRINGING HEAVY SPRING
RAINS BEFORE THE SOILS THAW AND BECOME AVAILABLE TO INFILTRATION OF
MELTWATER AND RAINFALL.
UNTIL SUCH TIME AS THE GROUND SURFACE THAWS, ANY SPRING RAIN OR
MELTING OF FUTURE SNOW WILL CREATE A SURPRISINGLY GENEROUS AMOUNT OF
RUNOFF FROM A GIVEN AMOUNT OF RAIN OR SWE CONTENT ON THE GROUND.
LASTLY, WARM WEATHER DURING THE FIRST WEEK OF MARCH WILL FURTHER
MELT AND ERODE THE SNOWPACK ACROSS THE MISSOURI AND JAMES RIVER
BASINS. HOWEVER, THE EXTENT OF THIS MELT AND HOW MUCH RUNOFF WILL BE
GENERATED FROM THIS WARM SPELL IS JUST A LITTLE TOO FAR IN THE
FUTURE FOR MUCH CERTAINTY.
..SNOWPACK CONDITIONS
WHILE THE SNOW ACCUMULATION SEASON HAD A ROBUST BEGINNING IN EARLY
DECEMBER, MOST OF THE MISSOURI AND JAMES RIVER BASINS HAVE SINCE
LOST MUCH OF THEIR SNOWPACK TO MELTING AND SUBLIMATION. MUCH, BUT
NOT ALL, OF THIS MELTWATER RAN INTO THE LOCAL STREAMS AND IS NOW
DRAINED OFF THE COUNTRYSIDE.
WHAT REMAINS NOW ACROSS MOST OF THE JAMES AND MISSOURI RIVER BASINS
IS SWE IN THE FORM OF ICE ON THE GROUND SURFACE, OR A RECENTLY
RECEIVED MODEST SNOWPACK. IN THE SOUTHWESTERN CORNER OF THE STATE,
SWE CONTENT IS NOW WELL BELOW ONE-HALF OF AN INCH, AND BUILDS
SLIGHTLY TO AROUND TWO INCHES OF SWE IN THE UPPER JAMES RIVER BASIN.
IN AND OF ITSELF, THE EXISTING SNOWPACK DOES NOT CREATE MUCH
CONCERN, BUT UP TO SEVERAL WEEKS REMAIN IN THE SNOW ACCUMULATION
SEASON. NONETHELESS, IT REMAINS TO BE SEEN HOW MUCH TOTAL SWE WILL
BE ON THE GROUND FOR THE EVENTUAL SPRING MELT SEASON. SWE TOTALS
NEARING THREE ACROSS LARGE AREAS WOULD BE CAUSE FOR CONCERN THIS
YEAR GIVEN THE DEMONSTRATED IMPERMEABLE NATURE OF THE SURFACE SOILS.
..THE MISSOURI AND YELLOWSTONE RIVERS WEST OF WILLISTON
THE MISSOURI AND YELLOWSTONE RIVERS WEST OF WILLISTON ARE SLIGHTLY
ELEVATED FOR THIS TIME OF YEAR AS RUNOFF FROM THE EARLY FEBRUARY
MELT CONTINUES MAKING ITS WAY TOWARDS LAKE SAKAKAWEA. WHILE FLOODING
IS NOT A LARGE CONCERN AT THIS POINT, UNSTABLE ICE ALONG THE
FREE-FLOWING PORTIONS OF THE YELLOWSTONE AND MISSOURI RIVERS WEST OF
WILLISTON IS A DANGER TO OUTDOOR ENTHUSIASTS RECREATING ON AND ALONG
THE RIVERS.
..THE MISSOURI RIVER BELOW GARRISON DAM
THE MISSOURI RIVER BELOW GARRISON DAM IS LARGELY OPEN DOWN THROUGH
THE WASHBURN AREA. FROM WILTON TO THE BISMARCK/MANDAN AREA, THERE
ARE A FEW SPOTS SHOWING OPEN WATER BUT IT GENERALLY REMAINS COVERED
IN ICE. THIS SUGGESTS THAT EVEN WITH SEASONABLE TEMPERATURES, ENOUGH
ICE REMAINS ON THE MISSOURI RIVER TO PRODUCE ICE JAM(S) IF THE
REGION WERE TO EXPERIENCE A SUDDEN LARGE RUNOFF EVENT. FOR EXAMPLE,
A WARM COLORADO LOW STORM SYSTEM BRINGING EXCESSIVE RAINFALL TO THE
AREA BEFORE THE SOILS THAW SUFFICIENTLY TO RESTORE THE SOIL'S
ABILITY TO MINIMIZE RUNOFF, WOULD BE SUCH AN EVENT.
..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 ALREADY AT, OR BELOW THEIR NORMAL DRAW-DOWN LEVELS IN
PREPARATION FOR THE EVENTUAL SPRING MELT SEASON. THIS SUGGESTS THAT
LOCAL WATER STORAGE WILL PROVIDE A NORMAL AMOUNT OF FLOOD MITIGATION
COME THE SPRING MELT SEASON. MANY SMALLER WATER STORAGE FEATURES,
SUCH AS STOCK DAMS AND DUGOUTS HAVE ALREADY EXPERIENCED CONSIDERABLE
RISES DUE TO THE FEBRUARY MELTING OFF OF THE LOCAL SNOWPACK.
..SOIL CONDITIONS
SOIL TEMPERATURES ARE HIGHLY VARIED THIS YEAR. IN PLACES WHERE THE
SNOW LARGELY MELTED OFF DURING THE MULTIPLE WARM PERIODS IN LATE
DECEMBER, EARLY JANUARY AND AGAIN IN EARLY FEBRUARY ARE NOW POORLY
INSULATED AND THIS HELPS INCREASE FROST DEPTH. BELOW FREEZING
TEMPERATURES CAN GO DOWN TO AROUND 30 INCHES IN SOME AREAS, WITH
ABOUT 24 INCHES BEING NORMAL. THESE SOIL TEMPERATURES ARE GENERALLY
NEAR NORMAL FOR THIS TIME OF YEAR. WHAT IS QUITE A BIT MORE UNUSUAL
IS THE SOIL MOISTURE PROFILE ACROSS THE MISSOURI AND JAMES RIVER
BASINS. SINCE THE EARLY SNOW FELL ON WARM SOILS AND SUBSEQUENTLY
EXPERIENCED A LOT OF MELTING, THE GROUND SURFACE AND NEAR SURFACE
SOILS BECAME VERY WET. A SECOND WARM PERIOD IN EARLY FEBRUARY
CREATED A SURPRISINGLY GENEROUS RUNOFF FROM THAT MELTING SNOW AND
ICE DUE TO THE NEAR IMPERMEABLE GROUND SURFACE.
..WEATHER OUTLOOK
THE NEAR-TERM 6-10 AND 8-14 DAY WEATHER OUTLOOKS FAVOR ABOVE NORMAL
TEMPERATURES AND ABOVE NORMAL PRECIPITATION. THE ONE-MONTH OUTLOOKS
FOR THE MONTH OF MARCH PUTS ALL OF THE JAMES AND MISSOURI RIVER
BASINS IN THE EQUAL CHANCES CATEGORY FOR BELOW NORMAL, NEAR NORMAL,
OR ABOVE NORMAL TEMPERATURE AND PRECIPITATION.
LOOKING EVEN LONGER TERM, THE 3-MONTH OUTLOOKS COVERING MARCH,
APRIL, AND MAY ALSO PLACE THIS AREA IN THE EQUAL CHANCES CATEGORY
FOR TEMPERATURE AND 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: 03/01/2026 - 05/30/2026
: 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 : 6 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 : <5 27 <5 10 <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 : 12 58 <5 <5 <5 <5
:BEAVER CREEK
LINTON 12.0 14.0 16.0 : 19 41 <5 31 <5 13
:LITTLE MUDDY RIVER
WILLISTON 10.0 12.0 14.0 : 10 66 <5 33 <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 : 6 18 5 9 <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 : <5 20 <5 <5 <5 <5
:SPRING CREEK
ZAP 14.0 18.0 20.0 : 6 25 <5 14 <5 8
:KNIFE RIVER
HAZEN 21.0 24.0 25.0 : 8 43 7 25 <5 23
:HEART RIVER
MANDAN 27.0 33.0 38.0 : <5 20 <5 <5 <5 <5
:APPLE CREEK
MENOKEN 15.0 16.0 17.0 : 37 55 20 52 <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: 03/01/2026 - 05/30/2026
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:PIPESTEM
PINGREE 5.2 5.2 5.3 5.6 6.2 9.1 10.5
:JAMES RIVER
GRACE CITY 5.5 5.5 5.7 6.1 6.9 11.1 13.5
LAMOURE 7.8 7.8 7.9 8.4 10.8 13.1 13.8
:MISSOURI RIVER
WILLISTON 16.1 16.3 16.9 17.4 18.4 19.2 21.2
:CANNONBALL RIVER
REGENT 5.2 5.3 6.1 6.7 7.5 8.7 9.4
:CEDAR CREEK
RALEIGH 2.2 2.7 3.1 4.4 5.5 6.4 6.6
:CANNONBALL RIVER
BREIEN 3.4 3.8 4.7 6.7 8.4 10.6 11.3
:BEAVER CREEK
LINTON 5.8 5.9 6.6 8.8 11.3 12.8 13.0
:LITTLE MUDDY RIVER
WILLISTON 5.2 5.2 5.7 6.9 8.8 10.0 11.6
:LITTLE MISSOURI RIVER
MARMARTH 1.4 1.4 2.8 4.7 6.2 12.0 16.5
MEDORA 3.7 3.7 4.5 5.6 8.0 13.2 17.1
WATFORD CITY 8.4 8.5 10.4 11.5 13.6 16.7 20.2
:KNIFE RIVER
MANNING 6.2 6.2 7.1 8.1 9.1 10.5 12.8
:SPRING CREEK
ZAP 5.2 5.7 7.0 7.7 9.6 11.9 14.8
:KNIFE RIVER
HAZEN 1.2 2.0 6.0 9.1 13.6 17.3 24.8
:HEART RIVER
MANDAN 12.2 12.3 14.1 15.5 18.4 20.4 24.2
:APPLE CREEK
MENOKEN 5.7 5.9 9.1 13.1 15.7 16.7 17.0
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: 03/01/2026 - 05/30/2026
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:PIPESTEM
PINGREE 5.0 5.0 4.9 4.8 4.8 4.8 4.8
:JAMES RIVER
GRACE CITY 4.0 4.0 4.0 4.0 4.0 4.0 4.0
LAMOURE 7.6 7.6 7.5 7.1 6.9 6.8 6.8
:MISSOURI RIVER
:CANNONBALL RIVER
REGENT 4.9 4.9 4.8 4.8 4.8 4.8 4.8
:CEDAR CREEK
RALEIGH 0.8 0.8 0.7 0.6 0.5 0.4 0.4
:CANNONBALL RIVER
BREIEN 2.1 2.1 2.0 1.9 1.8 1.7 1.7
:BEAVER CREEK
LINTON 4.7 4.7 4.5 4.5 4.4 4.4 4.4
:LITTLE MUDDY RIVER
WILLISTON 4.7 4.6 4.5 4.5 4.5 4.5 4.5
:LITTLE MISSOURI RIVER
MARMARTH 1.4 1.3 1.3 1.3 1.3 1.3 1.3
MEDORA 2.5 2.4 2.4 2.4 2.3 2.3 2.3
WATFORD CITY 8.2 8.2 8.2 8.2 8.1 8.1 8.1
:KNIFE RIVER
MANNING 6.2 6.2 6.1 6.1 6.0 6.0 6.0
:SPRING CREEK
ZAP 4.8 4.8 4.7 4.7 4.7 4.7 4.7
:KNIFE RIVER
HAZEN 0.7 0.7 0.6 0.5 0.5 0.3 0.3
:HEART RIVER
MANDAN 10.7 10.6 10.6 10.5 10.4 10.3 10.3
:APPLE CREEK
MENOKEN 4.8 4.8 4.7 4.1 3.9 3.5 3.5
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/BIS FOR MORE WEATHER AND WATER
INFORMATION.
THE NEXT OUTLOOK WILL BE ISSUED BY 12 MARCH.
SCHLAG
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