Flood Potential Outlook
Issued by NWS Bismarck, ND
Issued by NWS Bismarck, ND
433
FGUS73 KBIS 141613
ESFBIS
NDC009-013-023-049-061-069-075-079-101-161400-
Probabilistic Hydrologic Outlook
National Weather Service Bismarck ND
1113 AM CDT Thu Mar 14 2024
...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 18 March through
16 June, 2024. This is the third and final edition of the
Spring Flood and Water Resources Outlook. On 28 March, the NWS will
revert back to routinely issuing of flood probabilities 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
normal/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 snowpack across the Souris River basin has been in the process
of melting its snowpack on and off again over the past few weeks. In
general though, the North Dakota portion of the basin will largely
be free of substantial snow cover by the end of this second full
week of March. At this point, no flood concerns have arisen, but
forecast points such as Towner and Bantry on the Souris River, or
Willow City on Willow Creek, still have a fairly decent chance of
minor flooding.
Overall though, widespread flooding at this point does not appear to
be a significant concern without remarkably large amounts of spring
rain.
...Snowpack Conditions...
The snowpack, along with its associated Snow-Water Equivalent (SWE)
had received a significant boost over the past couple of weeks from
a couple of notable winter storms. However, it is still widely well
below normal to somewhat below normal across the entire basin. And
again, since the region has been experiencing periods of well above
normal temperatures, significant loss of the snowpack has already
been observed and is expected to continue over the coming several
days.
...Soil Conditions...
Soil moisture values across the Souris River Basin are very high in
the Long Creek watershed and somewhat above normal to near normal in
other parts of the Souris River basin.
Frost depth is highly variable this year as a mix of very warm
weather in December and a good part of January has helped prevent
extensive freezing of the soil, but up to 30 inches of frost depth
has been observed in some areas of the basin within North Dakota.
...Current Drought Conditions...
The U.S. Drought Monitor reflects D0 (Abnormally Dry) to D1
(Moderate Drought) across the Souris River Basin of North Dakota.
Given the time of year, no significant impacts are noted with the
current drought designations. However, concerns with increased
drought designations going into spring are warranted, especially
since climate outlooks and near-term forecasts do not favor a change
in existing trends anytime soon.
...Reservoirs and Natural Wetlands...
Lake Darling above Minot along with the Canadian reservoirs behind
Grant Devine and Rafferty Dams have their full flood control
storage available for spring runoff. The majority of natural
wetlands and lakes also are at, or near normal water levels going
into spring.
...Weather Outlook...
The Climate Prediction Center 6-10 and 8-14 day outlooks favor below
normal temperatures and above normal chances for precipitation. That
generally carries the state through the remainder of March, however
the weeks 3-4 outlooks bring back a fairly strong favoring of above
normal temperatures with a slight to strong favoring of below normal
precipitation. Looking longer term at the three-month outlook for
March, April, and May...a favoring for above normal temperatures
with precipitation placed in the equal chances category for above
normal, near normal, or below normal precipitation.
...Ice Conditions...
After recent warm weather, not all rivers remain covered in ice.
Lakes and wetlands are generally still ice covered, but thickness is
generally less than normal and as runoff is currently being
generated, ice stability, thickness, and quality is lessening with
each passing day.
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: 03/18/2024 - 06/16/2024
: 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 : 17 37 6 16 <5 <5
Minot 1562.0 1565.0 1570.0 : 6 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 : 9 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 : 6 17 <5 <5 <5 <5
:Wintering
Karlsruhe 1509.0 1511.0 1512.0 : 8 14 <5 <5 <5 <5
:Souris
Towner 1454.0 1456.0 1458.0 : 37 61 12 28 <5 <5
Bantry 1440.0 1441.0 1443.0 : 37 61 23 41 <5 8
:Willow Creek
Willow City 1442.0 1446.0 1448.0 : 59 48 10 20 <5 <5
:Souris
Westhope 1414.0 1418.0 1420.0 : 21 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:03/18/2024 - 06/16/2024
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Des Lacs
Foxholm 1639.9 1640.1 1640.7 1642.1 1643.6 1645.7 1647.5
:Souris
Sherwood 1611.7 1612.8 1613.6 1614.7 1618.6 1620.0 1621.0
Foxholm 1570.4 1570.5 1570.7 1571.0 1571.5 1573.2 1576.3
Minot 1553.5 1553.6 1554.1 1554.6 1555.4 1557.6 1563.1
Minot 1542.4 1542.5 1542.8 1543.1 1543.6 1544.5 1547.3
Logan 1526.3 1526.4 1526.6 1527.3 1530.1 1533.8 1537.0
Sawyer 1512.1 1512.1 1512.2 1512.8 1516.3 1521.6 1522.7
Velva 1496.3 1496.4 1496.4 1496.7 1501.4 1506.5 1507.2
:Wintering
Karlsruhe 1504.0 1504.0 1504.0 1506.2 1507.5 1508.9 1509.3
:Souris
Towner 1450.9 1451.2 1451.9 1453.1 1455.0 1456.4 1456.9
Bantry 1436.3 1436.4 1437.2 1439.0 1440.9 1442.0 1442.4
:Willow Creek
Willow City 1437.5 1437.9 1438.7 1443.0 1444.7 1446.0 1447.1
:Souris
Westhope 1411.2 1411.2 1411.7 1412.5 1413.8 1415.4 1417.4
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: 03/18/2024 - 06/16/2024
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Des Lacs
Foxholm 1639.4 1639.4 1639.3 1639.2 1638.9 1638.8 1638.8
:Souris
Sherwood 1606.8 1606.6 1606.4 1606.2 1606.0 1605.8 1605.8
Foxholm 1566.5 1566.5 1566.5 1566.5 1566.5 1566.5 1566.5
Minot 1551.3 1551.2 1551.1 1550.9 1550.7 1550.6 1550.6
Minot 1541.6 1541.5 1541.5 1541.3 1541.2 1541.1 1541.1
Logan 1522.2 1521.6 1520.5 1520.1 1519.9 1519.8 1519.8
Sawyer 1508.7 1508.2 1507.7 1507.2 1506.7 1506.6 1506.6
Velva 1492.3 1492.2 1491.3 1490.7 1490.2 1490.2 1490.2
:Wintering
Karlsruhe 1503.7 1503.6 1503.5 1503.1 1503.0 1503.0 1503.0
:Souris
Towner 1444.4 1444.4 1444.4 1444.4 1444.4 1444.4 1444.4
Bantry 1430.4 1430.4 1430.4 1430.4 1430.4 1430.4 1430.4
:Willow Creek
Willow City 1437.1 1437.0 1436.9 1436.8 1436.1 1436.1 1436.1
:Souris
Westhope 1410.5 1410.4 1410.3 1410.2 1409.6 1409.4 1409.4
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 March.
$$
Schlag