FGUS73 KABR 120825 ESFABR MNC011-155-SDC013-017-021-025-029-031-037-039-041-045-049-051-057- 059-065-069-075-085-089-091-107-109-115-117-119-129-062000- Probabilistic Hydrologic Outlook National Weather Service Aberdeen SD 325 AM CDT Thu Mar 12 2026 ...Spring Flood and Water Resources Outlook... This Spring Flood and Water Resources Outlook is for the Aberdeen Hydrologic Service Area (HSA), which covers portions of central and northeast South Dakota, along with west central Minnesota. The main river basins include the Missouri, James, Big Sioux, Minnesota, Bad, Moreau, and Grand rivers. Flooding potential remains below normal across much of the HSA, although potential has increased slightly on the James River since the last outlook on February 26th. Additional snow melt, along with deep frost and added soil moisture over northern South Dakota led to the increased potential. The James River at Columbia now has a 52 percent chance to reach minor flood stage, while the James River at Stratford has a 56 percent chance. All other sites across the HSA have a less than 50 percent chance of reaching minor flood stage through the middle of June. Below normal precipitation this winter and a lack of existing snow cover bring a below normal flood risk this spring. While there is a lack of snow cover, we do have frost depths of 0.5 to 2 feet across northern South Dakota. This would bring concern for increased runoff should a heavy spring rain event occur prior to removal of frost from the ground. Precipitation trends into early spring will continue to be monitored and will likely be the primary driver for future flood 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: 03/16/2026 - 06/14/2026 : 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 : 52 58 28 42 11 29 Stratford 14.0 17.0 18.5 : 56 58 22 41 6 32 Ashton 13.0 14.0 16.0 : 32 58 27 47 23 42 Redfield 20.0 22.0 25.0 : 14 45 12 44 10 42 :Snake Creek Ashton 11.5 13.0 16.0 : 18 53 16 53 12 43 :Turtle Creek :Big Sioux River Watertown 10NW 10.0 11.0 12.0 : <5 18 <5 <5 <5 <5 Watertown Conifer 9.0 10.0 12.0 : <5 37 <5 28 <5 <5 Watertown Broadwy 10.5 11.0 13.5 : <5 35 <5 34 <5 <5 Castlewood 9.0 11.0 16.0 : 8 35 <5 28 <5 <5 :Grand River Little Eagle 15.0 17.0 21.0 : <5 27 <5 19 <5 7 :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 : 24 25 <5 <5 <5 <5 :Minnesota River Big Stone Lake 970.0 971.5 973.5 : <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 5.0 5.0 5.1 5.9 8.3 11.3 13.0 :James River Columbia 11.0 11.1 11.5 13.1 16.4 18.1 19.1 Stratford 12.4 12.6 12.7 14.3 16.6 17.8 19.2 Ashton 8.0 8.1 8.8 11.1 14.7 17.3 26.2 Redfield 7.3 7.4 8.1 10.5 14.2 24.5 31.5 :Snake Creek Ashton 2.5 2.5 2.8 5.5 8.9 16.7 19.6 :Turtle Creek :Big Sioux River Watertown 10NW 4.4 4.4 4.7 6.4 7.1 8.2 8.8 Watertown Conifer 4.5 4.5 4.7 5.5 6.3 7.4 8.2 Watertown Broadwy 5.2 5.2 5.4 6.3 7.3 9.0 9.9 Castlewood 5.1 5.2 5.3 6.2 7.1 8.8 9.8 :Grand River Little Eagle 3.8 3.9 5.0 6.4 8.3 9.0 10.6 :Moreau River White Horse 2.7 4.0 6.6 7.9 11.2 13.9 17.1 :Bad River Fort Pierre 0.5 1.7 3.5 6.2 12.6 19.6 23.0 :Little Minnesota Peever 13.5 13.7 14.0 15.0 16.8 18.3 20.5 :Minnesota River Big Stone Lake 966.5 966.5 966.5 966.5 967.1 968.6 969.8 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 4.5 4.5 4.4 4.3 4.3 4.2 4.2 :James River Columbia 9.1 9.0 7.7 6.6 6.4 6.3 6.2 Stratford 11.2 11.1 9.5 8.6 8.3 8.2 8.2 Ashton 7.5 7.5 6.6 5.6 4.9 4.8 4.8 Redfield 6.9 6.9 6.7 5.8 5.0 4.9 4.9 :Snake Creek Ashton 2.2 2.0 1.8 1.7 1.5 1.5 1.5 :Turtle Creek :Big Sioux River Watertown 10NW 3.9 3.7 3.7 3.7 3.7 3.7 3.7 Watertown Conifer 4.2 4.2 4.2 4.2 4.2 4.2 4.2 Watertown Broadwy 5.0 5.0 5.0 4.9 4.9 4.9 4.9 Castlewood 4.7 4.7 4.6 4.5 4.5 4.5 4.5 :Grand River Little Eagle 3.8 3.8 3.8 3.7 3.7 3.7 3.7 :Moreau River White Horse 2.4 2.4 2.4 2.4 2.3 2.3 2.3 :Bad River Fort Pierre 0.5 0.5 0.5 0.5 0.5 0.5 0.5 :Little Minnesota Peever 0.1 0.1 0.0 0.0 0.0 0.0 0.0 :Minnesota River 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. The next outlook will be issued by the end of April. $$ TMT