Flood Potential Outlook
Issued by NWS Aberdeen, SD
Issued by NWS Aberdeen, SD
315 FGUS73 KABR 141813 ESFABR MNC011-155-SDC013-017-021-025-029-031-037-039-041-045-049-051-057- 059-065-069-075-085-089-091-107-109-115-117-119-129-081900- Probabilistic Hydrologic Outlook National Weather Service Aberdeen SD 113 PM CDT Thu Mar 14 2024 ...Spring Flood Outlook... This spring flood outlook is for the rivers and streams in northeast South Dakota, portions of central South Dakota, and portions of west central Minnesota. A current lack of snow cover, areas of thawed ground, and minimal remaining areas of river ice currently point toward a below normal flood risk over the area over the next 90 days. With this said, additional heavy precipitation events or cold outbreaks could change the flood risk going forward. Changes to the flood risk factors will continue to be monitored. The outlook for the next two weeks is for increased chances for below normal temperatures and above normal precipitation. The 90 day outlook for March through May indicates increased chances for above normal temperatures, and equal chances for below, near or above normal precipitation. ...Current snow conditions... Above normal temperatures allowed any remaining snow cover to melt in the past couple of weeks, with the entire area now snow free. ...Current soil conditions... Soil moisture is near to above normal across the entire area. Frost depths are generally around or below one foot across the northern part of the area, and the ground is thawed across south central South Dakota. The areas currently in drought at this time are all of Codington, Deuel, Hamlin, Brown, McPherson, Campbell and Corson counties, and portions of Roberts, Marshall, Day, Edmunds, Walworth, Dewey, Grant, and Clark counties in South Dakota and Big Stone and Traverse counties in Minnesota. ...Current river conditions... Quite a bit of river ice has melted. Any possible cold spells over the next few months could lead to ice reformation. River levels and flows are generally running near to above normal along the James River and points west, while most other locations running near to slightly below normal. ...Probabilistic Outlooks... 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: 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 -------- ----- ----- ----- : --- --- --- --- --- --- :Elm River Westport 14.0 16.0 19.0 : <5 28 <5 22 <5 9 :James River Columbia 13.0 16.0 18.0 : 11 55 6 41 5 29 Stratford 14.0 17.0 18.5 : 14 58 6 40 5 29 Ashton 13.0 14.0 16.0 : 8 58 7 47 6 42 Redfield 20.0 22.0 25.0 : 10 45 9 44 7 42 :Snake Creek Ashton 11.5 13.0 16.0 : 10 52 6 43 6 31 :Turtle Creek Redfield 7.0 10.0 15.0 : 23 54 17 46 11 30 :Big Sioux River Watertown 10NW 10.0 11.0 12.0 : <5 19 <5 <5 <5 <5 Watertown Conifer 9.0 10.0 12.0 : <5 37 <5 32 <5 <5 Watertown Broadwy 10.5 11.0 13.5 : <5 35 <5 34 <5 <5 Castlewood 9.0 11.0 16.0 : 6 43 <5 28 <5 <5 :Grand River Little Eagle 15.0 17.0 21.0 : <5 27 <5 17 <5 6 :Moreau River White Horse 21.0 23.0 25.0 : <5 22 <5 17 <5 11 :Bad River Fort Pierre 21.0 25.0 27.0 : 6 12 <5 5 <5 <5 :Little Minnesota Peever 17.0 22.0 24.0 : 10 27 <5 <5 <5 <5 :Minnesota River Big Stone Lake 971.5 973.0 975.0 : <5 6 <5 <5 <5 <5 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: Location 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Elm River Westport 4.7 4.7 4.7 5.0 7.6 10.6 12.5 :James River Columbia 6.7 6.7 6.7 6.9 10.5 13.5 17.3 Stratford 8.1 8.1 8.1 8.1 11.9 15.5 18.0 Ashton 4.9 4.9 4.9 4.9 6.6 10.9 21.9 Redfield 5.8 5.8 5.8 5.9 8.0 20.1 29.0 :Snake Creek Ashton 2.9 2.9 2.9 3.5 6.0 11.4 17.6 :Turtle Creek Redfield 3.9 3.9 3.9 4.5 6.3 15.5 16.3 :Big Sioux River Watertown 10NW 4.1 4.2 4.5 5.8 6.6 8.0 8.7 Watertown Conifer 3.7 3.7 3.9 4.7 5.2 6.4 7.6 Watertown Broadwy 5.5 5.5 5.6 6.3 6.8 8.4 9.4 Castlewood 5.3 5.4 5.6 6.2 7.0 8.4 9.5 :Grand River Little Eagle 2.9 3.0 4.5 5.6 8.2 9.2 10.6 :Moreau River White Horse 2.5 3.3 5.2 6.4 9.4 12.8 16.0 :Bad River Fort Pierre 1.4 1.7 3.6 6.8 13.6 20.4 23.5 :Little Minnesota Peever 10.4 10.5 11.4 13.2 15.2 17.0 19.0 :Minnesota River Big Stone Lake 967.9 967.9 968.0 968.0 968.0 968.5 969.5 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: LOCATION 95% 90% 75% 50% 25% 10% 5% -------- ------ ------ ------ ------ ------ ------ ------ :Elm River Westport 4.3 4.0 3.9 3.9 3.8 3.8 3.6 :James River Columbia 6.4 6.2 5.8 5.3 5.1 5.0 5.0 Stratford 7.2 6.9 6.6 6.3 6.0 5.9 5.9 Ashton 4.4 4.3 4.0 3.5 3.3 3.2 3.2 Redfield 5.3 5.2 5.0 4.7 4.5 4.4 4.4 :Snake Creek Ashton 2.9 2.9 2.9 2.9 2.9 2.9 2.9 :Turtle Creek Redfield 3.4 3.3 3.2 3.1 3.1 3.1 3.1 :Big Sioux River Watertown 10NW 4.0 3.8 3.8 3.8 3.8 3.8 3.8 Watertown Conifer 3.7 3.7 3.6 3.6 3.6 3.6 3.6 Watertown Broadwy 5.4 5.4 5.3 5.3 5.2 5.2 5.2 Castlewood 5.1 5.0 4.9 4.8 4.8 4.7 4.7 :Grand River Little Eagle 2.6 2.6 2.6 2.6 2.6 2.5 2.4 :Moreau River White Horse 2.3 2.3 2.2 2.2 2.2 2.2 2.1 :Bad River Fort Pierre 0.5 0.5 0.5 0.5 0.5 0.5 0.5 :Little Minnesota Peever 10.4 10.2 9.7 9.7 9.7 9.7 9.7 :Minnesota River Big Stone Lake 967.7 967.7 967.7 967.7 967.7 967.7 967.7 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/abr for more weather and water information. This is the final spring flood outlook for the season. The next regular monthly outlook will be issued by the end of March. $$ Parkin