436
FGUS73 KBIS 121545
ESFBIS
NDC009-013-023-049-069-075-079-101-122345-
PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE BISMARCK ND
1045 AM CDT THU MAR 12 2026
..SPRING FLOOD AND WATER RESOURCES OUTLOOK
THIS SPRING FLOOD AND WATER RESOURCES OUTLOOK IS FOR THE SOURIS
RIVER BASIN OF NORTH DAKOTA, COVERING THE PERIOD OF 16 MARCH
THROUGH 14 JUNE, 2026. THIS OUTLOOK IS THE LAST OF THE THREE PART
SERIES COLLECTIVELY REFERRED TO AS THE SPRING FLOOD AND WATER
RESOURCES OUTLOOKS. 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. IN
REALITY, NWS-BISMARCK USES THE SAME GENERAL FORMAT FOR THE ROUTINE
MONTHLY FLOOD AND WATER RESOURCES OUTLOOKS AS IT DOES FOR THIS
NATIONALLY COORDINATED SERIES OF OUTLOOKS.
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
LATE FEBRUARY AIRBORNE SNOW SURVEYS REVEALED MORE THAN EXPECTED
AMOUNTS OF SNOW-WATER EQUIVALENT (SWE) IN THE SOURIS RIVER BASIN OF
NORTH DAKOTA. WHILE NOT MUCH NEW SNOW HAS BEEN RECEIVED ACROSS THE
SOURIS RIVER BASIN OVER THE PAST TWO WEEKS, THERE HAS INDEED BEEN
MELTING OF THE EXISTING SNOWPACK. RUNOFF FROM THIS MELTING SNOWPACK
IS NOW SHOWING UP AT EVERY FORECAST LOCATION IN THE SOURIS RIVER
BASIN OF NORTH DAKOTA; THUS FAR WITH NO HINT OF PROBLEMATIC HIGH
WATER. AT THIS POINT, IT WOULD APPEAR THAT THE CURRENT MELT PATTERN
WILL SLOW OVER THE NEXT SEVERAL DAYS BEFORE IT RESUMES AROUND THE
MIDDLE OF THE THIRD FULL WEEK OF MARCH.
THE EXISTING SLOW MELT HAS CLEARLY ESTABLISHED THE PATHWAYS FOR
MELTWATER TO TURN INTO RUNOFF AND MAKE ITS WAY TO THE LOCAL STREAMS.
THIS WILL SHORTEN THE TIME IT TAKES FOR THE RUNOFF TO MAKE IT TO THE
SOURIS RIVER AND ITS TRIBUTARIES GOING FORWARD. ONE BENEFIT TO
HAVING THIS GENTLE START TO THE SPRING RUNOFF SEASON IS THAT BY
DRAGGING THE MELT OUT OVER A LONGER TIME, THE OVERALL FLOOD RISK FOR
FORECAST LOCATIONS FROM THE SOURIS RIVER NEAR SHERWOOD ALL THE WAY
DOWN TO THE SOURIS RIVER AT VELVA ARE NEAR TO BELOW NORMAL FOR THIS
TIME OF YEAR. FROM TOWNER ON DOWNSTREAM TO WESTHOPE, INCLUDING
WILLOW CREEK, THE RISK OF AT LEAST MINOR FLOODING IS SLIGHTLY ABOVE
TO WELL ABOVE NORMAL. THIS IS MOSTLY DUE TO THE GREATER SNOW-WATER
EQUIVALENT FOUND IN THE TURTLE MOUNTAIN AREA.
OVERALL, THE WET AND FROZEN SOILS ARE STILL A MAJOR CONTRIBUTOR TO
THE RISK OF WIDESPREAD FLOODING WITH THE EXCEPTION BEING IN THE
WILLOW CREEK WATERSHED, WHICH HAS NOT YET EXPERIENCED THE LEVEL OF
MELTING AS THE REST OF THE SOURIS RIVER BASIN OF NORTH DAKOTA. UNTIL
SUCH TIME AS THE SOILS BEGIN TO THAW, ANY LARGE SPRING RAIN EVENT
WILL POSE THE GREATEST RISK TO WIDESPREAD FLOODING.
..SNOWPACK CONDITIONS
THE SNOW ACCUMULATION SEASON STARTED OUT WITH AN ABOVE NORMAL AMOUNT
OF SNOW AND ITS ACCOMPANYING SNOW-WATER EQUIVALENT (SWE) IN EARLY
DECEMBER. HOWEVER, A FAIRLY WARM STRETCH IN EARLY JANUARY MELTED
MUCH OF THE EARLY SNOWPACK, ESPECIALLY IN THE SOUTHERN AND WESTERN
PORTION OF THE SOURIS RIVER BASIN OF NORTH DAKOTA. WHILE THERE WAS
SURELY SOME SWE LOST TO EVAPORATION AND SUBLIMATION, MUCH OF THE
MELTWATER REMAINED ON THE COUNTRYSIDE AS ICE ON THE GROUND SURFACE,
OR FROZE AS IT INFILTRATED INTO THE COLD SOIL.
THE WESTERN AND SOUTHERN PORTIONS OF THE SOURIS RIVER BASIN OF NORTH
DAKOTA GENERALLY CONTAIN LESS THAN AN INCH OF SWE ABOVE GROUND,
WHILE THE TURTLE MOUNTAIN AREA CONTAINS AS MUCH AS THREE INCHES OF
SWE. THESE VALUES FOR THE AMOUNT OF WATER AVAILABLE TO MELT AND
CREATE RUNOFF ARE GENERALLY LOWER THAN PAST YEARS OF SIGNIFICANT
FLOODING. HOWEVER, WHEN COMBINED WITH LOWER THAN NORMAL PERMEABILITY
OF THE SOILS, UNDER THE RIGHT CONDITIONS THIS CAN STILL CREATE
SURPRISING AMOUNTS OF RUNOFF WHEN COMPARED TO ONE'S VISUAL
ASSESSMENT OF THE SNOWPACK ALONE.
..CURRENT DROUGHT CONDITIONS
THERE ARE NO DROUGHT DESIGNATIONS WITHIN THE SOURIS RIVER BASIN OF
NORTH DAKOTA.
..RESERVOIRS AND NATURAL WETLANDS
RESERVOIRS AND NATURAL WETLANDS ARE GENERALLY WELL WITHIN THE NORMAL
RANGE OF THEIR LONG-TERM TRENDS FOR THIS TIME OF YEAR. ALL FLOOD
CONTROL PROJECTS WERE AT, OR BELOW, THEIR DESIRED WINTER LEVELS IN
PREPARATION FOR THE SPRING MELT SEASON EVEN THOUGH THEY HAVE
RECENTLY STARTED TO FILL.
..SOIL CONDITIONS
AGAIN, DUE TO THE WIDESPREAD MELTING OF THE SNOWPACK OVER MUCH OF
THE SOURIS RIVER BASIN OF NORTH DAKOTA, NEAR SURFACE SOIL MOISTURE
TENDS TO BE VERY HIGH. THE UPPER 4 INCHES OF THE SOIL PROFILE WERE
AROUND THE 95TH PERCENTILE FOR THE VAST MAJORITY OF THE BASIN JUST A
COUPLE WEEKS AGO. WHILE THIS STATISTICAL DESCRIPTION HAS SOMEWHAT
DECREASED WITH TIME, IT IS MOSTLY ATTRIBUTED TO THE NATURAL INCREASE
IN SOIL MOISTURE AS THE REGION GOES THROUGH MARCH. IN GENERAL, THE
SOILS REMAIN WET, FROZEN, AND OF LOW PERMEABILITY OUTSIDE THE TURTLE
MOUNTAIN AREA.
SOIL TEMPERATURES ALSO VARY CONSIDERABLY ACROSS THE BASIN WITH AREAS
HAVING LITTLE SNOW TO INSULATE THE GROUND SHOWING BELOW FREEZING
TEMPERATURES DOWN TO AS MUCH AS 39 INCHES, WHILE AREAS HAVING BEEN
CONSISTENTLY COVERED WITH SNOW SINCE EARLY DECEMBER HAVING FREEZING
TEMPERATURES DOWN TO AROUND 20-31 INCHES.
IN SHORT, THE SOILS ALL ACROSS MUCH OF THE BASIN ARE WET, FROZEN,
AND WELL CAPABLE OF ENHANCING OBSERVED RUNOFF FROM A GIVEN SNOWPACK
OR EARLY SPRING RAIN EVENT. OR, IN THE MORE EXTREME OF CASES FOR A
SPRING MELT, A WARM RAIN EVENT ON TOP OF AN ALREADY MELTING SNOWPACK.
..WEATHER OUTLOOK
WHILE THE SHORT-TERM FORECAST IS GENERALLY COOL AND WET, THE 6-10
AND 8-14 DAY WEATHER OUTLOOKS FAVOR ABOVE NORMAL TEMPERATURES AND
ABOVE NORMAL PRECIPITATION FOR THE SOURIS RIVER BASIN. THE ONE-MONTH
OUTLOOK, COVERING ALL OF MARCH, PUTS ALL OF THE SOURIS RIVER BASIN
OF NORTH DAKOTA IN THE EQUAL CHANCES CATEGORY FOR ABOVE NORMAL, NEAR
NORMAL, OR BELOW NORMAL TEMPERATURES AND PRECIPITATION. LOOKING EVEN
LONGER TERM, THE 3-MONTH OUTLOOKS COVERING MARCH, APRIL, AND MAY
SLIGHTLY FAVORS BELOW NORMAL TEMPERATURES IN THE EASTERN PART OF THE
BASIN, WITH THE WESTERN PORTION IN THE EQUAL CHANCES CATEGORY.
PRECIPITATION IS ALSO IN THE EQUAL CHANCES CATEGORY FOR BELOW
NORMAL, NEAR NORMAL, OR ABOVE 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: 03/16/2026 - 06/14/2026
: 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
-------- ----- ----- ----- : --- --- --- --- --- ---
:DES LACS
FOXHOLM 1651.0 1653.0 1654.0 : <5 <5 <5 <5 <5 <5
:SOURIS
SHERWOOD 1623.0 1625.0 1630.0 : <5 11 <5 5 <5 <5
FOXHOLM 1573.0 1576.0 1578.0 : 19 36 9 16 <5 <5
MINOT 1562.0 1565.0 1570.0 : 7 16 5 6 <5 <5
MINOT 1551.0 1553.0 1557.0 : <5 <5 <5 <5 <5 <5
LOGAN 1536.0 1538.0 1540.0 : 11 19 <5 <5 <5 <5
SAWYER 1524.0 1526.0 1528.0 : <5 7 <5 <5 <5 <5
VELVA 1507.0 1512.0 1517.0 : 11 17 <5 <5 <5 <5
:WINTERING
KARLSRUHE 1509.0 1511.0 1512.0 : 14 14 <5 <5 <5 <5
:SOURIS
TOWNER 1454.0 1456.0 1458.0 : 85 61 33 28 <5 <5
BANTRY 1440.0 1441.0 1443.0 : 93 61 63 43 <5 9
:WILLOW CREEK
WILLOW CITY 1442.0 1446.0 1448.0 : >95 48 56 20 13 6
:SOURIS
WESTHOPE 1414.0 1418.0 1420.0 : 73 55 12 24 <5 17
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: 03/16/2026 - 06/14/2026
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:DES LACS
FOXHOLM 1641.8 1642.0 1642.6 1643.8 1645.7 1648.6 1649.2
:SOURIS
SHERWOOD 1613.1 1614.3 1615.4 1616.8 1619.7 1620.2 1621.0
FOXHOLM 1570.6 1570.7 1570.7 1570.9 1572.9 1576.0 1576.7
MINOT 1554.3 1554.4 1554.7 1555.5 1557.2 1560.5 1565.0
MINOT 1543.0 1543.0 1543.2 1543.7 1544.3 1545.5 1549.1
LOGAN 1527.1 1527.2 1527.6 1529.3 1532.8 1536.2 1537.7
SAWYER 1512.8 1512.9 1513.5 1516.0 1519.4 1522.8 1523.5
VELVA 1497.1 1497.2 1498.4 1501.5 1505.2 1507.6 1508.2
:WINTERING
KARLSRUHE 1506.5 1506.9 1507.3 1507.9 1508.5 1509.2 1509.5
:SOURIS
TOWNER 1453.7 1453.9 1454.2 1455.3 1456.3 1456.9 1457.3
BANTRY 1439.9 1440.1 1440.5 1441.3 1442.0 1442.6 1443.0
:WILLOW CREEK
WILLOW CITY 1444.3 1444.5 1445.1 1446.2 1447.0 1448.2 1448.8
:SOURIS
WESTHOPE 1413.1 1413.2 1413.9 1415.3 1416.5 1418.4 1419.2
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: 03/16/2026 - 06/14/2026
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:DES LACS
FOXHOLM 0.0 0.0 0.0 0.0 0.0 0.0 0.0
:SOURIS
SHERWOOD 0.1 0.0 0.0 0.0 0.0 0.0 0.0
FOXHOLM 0.0 0.0 0.0 0.0 0.0 0.0 0.0
MINOT 0.3 0.1 0.0 0.0 0.0 0.0 0.0
MINOT 0.4 0.1 0.1 0.0 0.0 0.0 0.0
LOGAN 0.6 0.2 0.1 0.0 0.0 0.0 0.0
SAWYER 0.6 0.2 0.1 0.1 0.0 0.0 0.0
VELVA 0.7 0.3 0.1 0.1 0.0 0.0 0.0
:WINTERING
KARLSRUHE 0.0 0.0 0.0 0.0 0.0 0.0 0.0
:SOURIS
TOWNER 0.0 0.0 0.0 0.0 0.0 0.0 0.0
BANTRY 0.0 0.0 0.0 0.0 0.0 0.0 0.0
:WILLOW CREEK
WILLOW CITY 0.0 0.0 0.0 0.0 0.0 0.0 0.0
:SOURIS
WESTHOPE 0.4 0.4 0.4 0.3 0.2 0.1 0.1
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 26 MARCH, 2026.
SCHLAG
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