Flood Potential Outlook
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
706
FGUS73 KBIS 231908
ESFBIS
NDC009-013-023-049-069-075-079-101-251800-
Probabilistic Hydrologic Outlook
National Weather Service Bismarck ND
108 PM CST Thu Jan 23 2025
...FLOOD AND WATER RESOURCES OUTLOOK...
This Flood and Water Resources Outlook is for the Souris River Basin
of North Dakota, covering the period of 27 January, 2025 through 27
April, 2025. This is a routine monthly issuance of flood
probabilities for NWS forecast locations. These probabilities are
issued on, or around, the fourth 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...
There are three locations at, or above, normal flood risk for the
upcoming spring melt based on current conditions. Those three
locations are the Souris River near Towner, Souris River near
Bantry, and Willow Creek near Willow City. The primary driver in
this enhanced risk is the already robust Snow-Water Equivalent (SWE)
in the snowpack on the eastern side of the Souris River Basin of
North Dakota. In particular, the Turtle Mountain area over to about
Upham already has up to four inches of SWE that will eventually flow
into Willow Creek and roughly the last 50 miles of the Souris River.
While there is still plenty of time left in this snow accumulation
season for the relative nature of this snowpack to continue its
above normal trajectory; it is also possible the region will receive
below normal snow going forward.
The other location of note is the Wintering River near Karlsruhe.
While its overall probability of reaching flood stage is much less
than the aforementioned sites, it is slightly above normal risk of
flooding at this point in time.
The remaining forecast locations across the Souris River basin are
below normal and not of great concern at this point. Some of this
lack of risk is due to dry to very dry soils under the current
snowpack. These dry soils under most spring melt conditions will be
available to reduce expected runoff from a given snowpack, including
much of the Souris River Basin in Saskatchewan.
That being said, a continuation of normal to above normal snowfall
in Saskatchewan and the western portion of the Souris River Basin in
North Dakota would be expected to raise the risk of at least minor
flooding at all points along the Souris River.
In general, conditions affecting the potential for flooding or the
continuation of drought in the western portion of the Souris River
Basin will change with each passing week until such time as the
spring melt season arrives.
The higher SWE values in Saskatchewan not only sit on fairly dry
soils, but are also located above Grant Devine (formerly known as
Alameda) and Rafferty dams. These dams currently possess above
normal capacities for capturing excess runoff come spring. This will
help minimize the potential for flooding along the Souris River
upstream of Velva, Logan, Sawyer, and Minot.
...Snowpack Conditions...
Snow-water Equivalent (SWE) trends have placed the higher SWE values
in the Turtle Mountain area, and again in the very upper portion of
the Souris River Basin in Saskatchewan. Between two and four inches
of water equivalent already cover those important areas, but between
one and two inches are still more common over the majority of the
basin.
...Current Drought Conditions...
Drought remains a concern across much of the westernmost portion of
the Souris River Basin of North Dakota. D2 (severe drought) exists
on the western side of the basin, but drought concerns lessen to a
D0 (unusually dry) designation by the time one gets into Bottineau
County.
...Reservoirs and Natural Wetlands...
Streamflow, natural wetlands and small water features range from
well below normal to the lower range of normal for this time of year.
...Soil Conditions...
Soil moisture values remain well below normal for this time of year,
especially in the western and central portion of the Souris River
Basin.
...Weather Outlook...
The near term 6-10 and 8-14 day outlooks generally favor above
normal temperatures in the short-term, and nearer normal
temperatures towards the back half of the outlook period.
Precipitation is favored in these shorter term outlooks to be near
normal to above normal in the short-term, and above normal in the
8-14 day outlook.
Looking a little longer out in the future, the weeks 3-4 outlooks,
favor below normal temperatures with an equal chance of above
normal, near normal, or below normal precipitation for the first
half of February.
Looking even longer term at the one-month (February) and three-month
outlooks (Feb-Apr), there is a strong favoring for below normal
temperatures with an equal chances designation for above normal,
near normal, or below normal precipitation.
...Ice Conditions...
Smaller streams and rivers are iced over at this point and should
remain that way until the spring melt season. Ice on reservoirs and
lakes is generally of near-normal thickness for this time of year.
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: 01/27/2025 - 04/27/2025
: 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 9 <5 <5 <5 <5
Foxholm 1573.0 1576.0 1578.0 : 14 28 <5 11 <5 <5
Minot 1562.0 1565.0 1570.0 : <5 13 <5 6 <5 <5
Minot 1551.0 1553.0 1557.0 : <5 <5 <5 <5 <5 <5
Logan 1536.0 1538.0 1540.0 : <5 15 <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 13 <5 <5 <5 <5
:Wintering
Karlsruhe 1509.0 1511.0 1512.0 : 16 13 <5 <5 <5 <5
:Souris
Towner 1454.0 1456.0 1458.0 : 53 49 9 21 <5 <5
Bantry 1440.0 1441.0 1443.0 : 55 50 23 33 <5 8
:Willow Creek
Willow City 1442.0 1446.0 1448.0 : 72 46 20 17 <5 <5
:Souris
Westhope 1414.0 1418.0 1420.0 : 18 42 <5 18 <5 16
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: 01/27/2025 - 04/27/2025
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Des Lacs
Foxholm 1640.0 1640.2 1640.6 1641.3 1642.3 1644.2 1645.6
:Souris
Sherwood 1609.7 1610.8 1613.3 1616.7 1620.3 1620.9 1621.3
Foxholm 1569.3 1569.4 1570.5 1571.0 1571.3 1574.0 1574.1
Minot 1552.1 1552.4 1554.0 1554.3 1554.7 1556.6 1557.5
Minot 1541.7 1541.8 1542.7 1543.0 1543.5 1544.4 1545.0
Logan 1523.8 1524.1 1526.4 1527.0 1528.2 1531.1 1534.1
Sawyer 1509.6 1510.1 1511.9 1512.6 1514.4 1517.9 1519.7
Velva 1492.9 1493.1 1496.1 1496.6 1498.7 1503.2 1505.3
:Wintering
Karlsruhe 1504.6 1504.7 1505.2 1507.7 1508.4 1509.3 1509.6
:Souris
Towner 1448.9 1449.8 1452.5 1454.2 1455.0 1456.0 1456.4
Bantry 1434.4 1435.5 1438.1 1440.2 1440.9 1441.7 1441.9
:Willow Creek
Willow City 1438.2 1438.5 1440.8 1444.5 1445.7 1447.0 1447.9
:Souris
Westhope 1411.4 1411.6 1412.0 1413.0 1413.6 1414.9 1415.6
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: 01/27/2025 - 04/27/2025
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 0.0 0.0 0.0 0.0 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 February 13th and is the first in
a series of three Spring Flood and Water Resources Outlooks. Below
is the full schedule for that series of outlooks.
First edition - Thursday, February 13th, 2025.
Second edition - Thursday, February 27th, 2025.
Third edition - Thursday, March 13th, 2025.
After the above Spring Flood and Water Resources Outlooks, the NWS
expects to revert back to its normally scheduled monthly release of
Flood and Water Resources Outlooks on, or about, 27 March, 2025.
$$
Schlag