Flood Potential Outlook
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
435
FGUS73 KBIS 131659
ESFBIS
NDC009-013-023-049-069-075-079-101-151700-
Probabilistic Hydrologic Outlook
National Weather Service Bismarck ND
1159 AM CDT Thu Mar 13 2025
...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 17 March, 2025
through 15 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...
Only the Willow Creek near Willow City has an above normal risk of
at least Minor flooding. This is largely due to the fairly robust
snowpack in the Turtle Mountain area with up to an estimated 2-4
inches of Snow-Water Equivalent remaining on the ground. There has
been a fair amount of melting off of the snowpack across most of the
plains portion of the Souris River Basin, both in North Dakota and
southern Saskatchewan. This leaves only the aforementioned Willow
Creek watershed and the Souris River basins above Rafferty and Grant
Devine dams with an appreciable amount of snow. Importantly though,
the vast majority of the runoff from these areas is expected to be
captured and stored in the reservoirs of these dams.
...Snowpack Conditions...
Snow cover is very uneven across the Souris River Basin. The Turtle
Mountain area has up to four inches of Snow-Water Equivalent (SWE),
while the vast majority of the plains portion of the basin contains
less than an inch of SWE overall. Above Rafferty and Grant Devine
dams in Saskatchewan, 2-4 inches of SWE exist. Due to having already
experienced a partial melt of the snow across the basin, much of the
snow that remains is concentrated in sheltered areas and drifts.
These conditions tend to produce a slower melt with somewhat less
runoff than would otherwise be expected from a more uniform snowpack.
...Current Drought Conditions...
No significant changes have occurred with respect to drought
designations over the past month. However, drought remains a concern
across the western half of the Souris River Basin of North Dakota
with up to a D2 (Severe) drought designation.
...Reservoirs and Natural Wetlands...
Due an earlier than normal melt of a very uneven, but generally
below normal snowpack this year, the net results will vary. Some
areas will likely experience near normal runoff, filling the smaller
natural and man-made water features, but other areas...especially in
the Long Creek and Des Lacs watersheds, may see well below normal
runoff.
...Soil Conditions...
Soil moisture values remain well below normal across much of the
Souris River Basin of not only North Dakota, but also up in
Saskatchewan. These dry soils remain fairly cold the farther north
one looks, but are still capable of infiltrating at least some of
the melting 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: 03/17/2025 - 06/15/2025
: 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
-------- ----- ----- ----- : --- --- --- --- --- ---
: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 : 14 37 <5 16 <5 <5
Minot 1562.0 1565.0 1570.0 : <5 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 : 6 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 : <5 17 <5 <5 <5 <5
:Wintering
Karlsruhe 1509.0 1511.0 1512.0 : 9 14 <5 <5 <5 <5
:Souris
Towner 1454.0 1456.0 1458.0 : 28 61 10 28 <5 <5
Bantry 1440.0 1441.0 1443.0 : 28 61 20 41 <5 8
:Willow Creek
Willow City 1442.0 1446.0 1448.0 : 65 48 9 20 <5 <5
:Souris
Westhope 1414.0 1418.0 1420.0 : 16 51 <5 22 <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: 03/17/2025 - 06/15/2025
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Des Lacs
Foxholm 1639.4 1639.4 1639.8 1640.7 1641.3 1642.5 1645.3
:Souris
Sherwood 1609.8 1610.2 1611.0 1613.3 1617.4 1620.3 1620.7
Foxholm 1569.4 1569.4 1570.0 1571.0 1571.2 1574.1 1575.3
Minot 1552.3 1552.3 1552.9 1554.1 1554.3 1556.4 1560.4
Minot 1541.7 1541.7 1542.1 1542.8 1543.0 1544.1 1545.7
Logan 1523.9 1523.9 1524.6 1526.6 1527.5 1532.7 1536.4
Sawyer 1509.9 1509.9 1510.4 1512.0 1513.3 1520.3 1522.2
Velva 1493.0 1493.0 1493.3 1496.0 1497.5 1505.1 1506.7
:Wintering
Karlsruhe 1504.1 1504.2 1504.3 1507.0 1507.8 1508.8 1509.4
:Souris
Towner 1446.0 1447.2 1449.7 1452.4 1454.8 1456.1 1456.7
Bantry 1431.7 1432.8 1435.3 1438.0 1440.7 1441.7 1442.3
:Willow Creek
Willow City 1438.0 1438.1 1439.4 1443.7 1444.9 1445.9 1447.4
:Souris
Westhope 1410.9 1411.1 1411.6 1412.4 1413.3 1415.1 1416.3
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: 03/17/2025 - 06/15/2025
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 0.0 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 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Minot 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Logan 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Sawyer 0.0 0.0 0.0 0.0 0.0 0.0 0.0
Velva 0.0 0.0 0.0 0.0 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 0.1 0.1 0.1 0.1 0.0 0.0 0.0
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.
$$
Schlag