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