Spring Hydrologic Outlook

Overall, the  conditional flood risk  for the  NCRFC  area this spring is below normal when compared to what is historically expected for the mid March to mid June outlook period. The exception is for rivers in the state of Missouri, the southern half of Iowa, and the southern half of Illinois where flood risk is near normal. 

Outside typical wet conditions from spring snowmelt and a brief wet period late last spring into early summer, drought conditions have plagued the NCRFC service area off and on since the summer of 2020. Following some record flooding that occurred across Minnesota and Iowa last June and July, dry conditions have been persistent across a majority of the service area since August 2024. These dry conditions set the northern NCRFC service area up for below average  soil moisture conditions  going into winter freeze-up.

The winter precipitation accumulation between December 2024 and March 2025 has been by and large below normal for the NCRFC area; with much of the area receiving 50-75 percent of normal precipitation.

NCRFC derives  Long Range Outlook  exceedance probability information for 448 forecast points. For this outlook, there are 30 forecast points in the NCRFC area that show a 50% or greater chance for minor flooding, with only one of those indicating a 50% or greater chance for moderate flooding. There are no forecast points currently showing a 50% or greater chance for major flooding.

This outlook is valid for March 17, 2025 - June 15, 2025.

A more detailed look at the conditions and risk by regional area is provided below. 

After a brief wet period late last spring into early summer, the remainder of 2024 returned to very dry conditions that were favorable for  drought . Nearly the entire  NCRFC service area  received below normal precipitation between August 2024 and March 2025; with much of the area receiving 50-75 percent of normal precipitation. At the end of July 2024, nearly all of the service area was out of drought classification; however, by November, 65 percent of the service area was classified as experiencing at least moderate drought. About 25 percent of the service area was classified as being in at least severe drought. The only areas in the NCRFC that remained without a drought/dry classification going into winter were some portions of north central North Dakota and the southern half of Missouri.

Despite the dry fall conditions, a heavy precipitation system that was a mixture of rain and snow occurred across the eastern Dakotas and much of Minnesota/Wisconsin in late November. This system dropped between an inch to two inches of liquid water equivalent immediately before temperatures dropped below freezing. Shortly thereafter, in the last few days of November, an Arctic Outbreak of cold air expanded across the Northern Plains through the Midwest that trapped a large portion of this liquid into the upper portions of the soil column for the winter. The late November system did improve drought conditions for northeastern North Dakota, central Minnesota, and central Wisconsin; however, the immediate drop in temperatures elevated concerns for future frozen ground runoff.

Since the late November wintry mix, precipitation across the NCRFC service area has been much below normal. As a result, the snow water equivalent (SWE) being simulated across the NCRFC area is also much below normal for this time of year. Currently there is no SWE south of central Minnesota, northern Wisconsin, and northern Michigan. With the exception of the areas affected frequently by lake-effect snowfall, such as the Upper Peninsula of Michigan and northern Lower Michigan, remaining SWE amounts are mostly within the bottom 10th percentile for SWE ranking at this time of year. The amounts of SWE that the NCRFC is simulating, especially in North Dakota, is expected to be slightly different than the  Office of Water Prediction’s values ; The NCRFC snow model is holding onto some liquid that has gone through several melt cycles throughout the winter but, due to frozen ground, the liquid remains in the upper soil column.

For temperatures, the months of September, October, and November had historically warm weather across the region. This warm weather increased evapotranspiration and contributed to accelerating the drought conditions. After the late November Arctic Outbreak, the winter has been characterized with drastic temperature swings with single digit temperatures reaching as far south as Louisiana in January to temperatures reaching above 50 in Minnesota later that very same month. These dramatic swings in temperature have resulted in the consolidation of snowpack and the formation of ice near the ground surface layer in areas that continue to carry generous  frost depths .

Due to the lack of snow to insulate the soil, coupled with multiple surges of bitter cold arctic air events, conditions have been favorable for developing deeper than average frost depths. For example, frost depths throughout Minnesota are typically between 15 and 25 inches at the end of February. Much of Minnesota is currently carrying at least 27 inches; and there are reports as high as 50 inches in eastern North Dakota. Frost depths slightly decreased since the last outlook and are expected to continue decreasing in the winter to spring transition period. Deep frost is considered a key ingredient for significant spring flooding because it increases the risk of excessive surface runoff in rapid melt-off, rain-on-snow, and heavy rainfall scenarios. Please note that this potential driver of flooding is not fully captured by the hydrologic model exceedance probabilities.

The  USGS WaterWatch  shows that, going into the fall freeze-up period, streamflow was Normal to Above Normal for much of the area. However, there was some variability across the NCRFC service area. Some heavy rains in early November elevated rivers to Much Above Normal to High for portions of Missouri and Illinois, although the streamflow at that time will have minimal impact on the Spring Outlook for these two states. However, it is worth noting that eastern North Dakota rivers were running Much Above Normal going into freeze-up; while many areas in northern Minnesota, northern Wisconsin, northern Lower Michigan, and the Upper Peninsula of Michigan were running Below Normal to Much Below Normal going into freeze-up. Currently, the  USGS 7-day average streamflow  across the NCRFC area is “Normal” to “Above Normal”.  This is expected since the temperatures have been favorable for snowmelt during the past week and have caused rivers to begin rising. 

There are no notable ice jams currently occurring in the NCRFC area. However, there are numerous areas being flagged for both freeze-up and break-up  ice jam potential  across the NCRFC in the current 7-day deterministic forecast window. With the lack of snow cover, rivers have accumulated more ice than usual this year, which has elevated the risk for ice jams.

Temperature Outlook: Overall, pattern trends favor continued warmer than normal temperatures across the NCRFC area into early April. For the longer range outlook through the end of May, the majority of the area is in equal chances for above, below, or near normal temperatures as there is no strong signal to indicate a consistent trend in one direction or another.

Precipitation Outlook: In the short term, an early spring system will bring a combination of snow and rain to the area. Precipitation amounts near one inch are possible mainly across western Minnesota. Looking further out, the Great Lakes region shows above normal precipitation is favored through spring overall. Farther west however, indications do not show a strong signal for future precipitation in terms of above or below normal. Hence, there are equal chances for above, below, or near normal precipitation amounts across this area which encompasses most of the NCRFC area.

For a more detailed discussion on specific watersheds, please continue reading below.

The  flood potential  is slightly below normal to below normal for most rivers across Minnesota, Wisconsin, and Iowa. The exceptions are some rivers that commonly receive spring flood impact attention, such as the Trempealeau, Baraboo, and Kickapoo Rivers in Wisconsin. These rivers have a near normal flood risk this spring. 

The below normal flood potential is being driven by the dry conditions that have been persistent across the region since August of that year. Where snow water equivalent (SWE) remains,  values for this time of year are in the bottom 10th percentile. Currently there is no SWE south of central Minnesota and northern Wisconsin. 

One key caveat to all the above information is deep frost depths. All three states are carrying above average frost depths for this time of year, which would increase the risk of excessive surface runoff in a heavy rainfall scenario. Lastly, the lack of snow cover has increased ice development on rivers in the area. The thicker ice conditions have increased the risk for ice jams. 

The  flood potential  in most parts of Illinois and Missouri is near normal to slightly below normal. The latest  U.S. Drought Monitor  and  USGS 7-day average streamflow  support the normal to slightly below normal long range flood risk. Drought conditions and below normal streamflows  have started to creep back into this region since the last outlook. Illinois and Missouri are currently snow free. 

The  flood potential  is below normal for the navigation portions of the mainstem Mississippi and Illinois Rivers. The current Long Range Outlook indicates that the mainstem Mississippi has around 15 to 30 percent below normal chances for exceeding Moderate Flood levels from St. Paul Minnesota down through Chester Illinois; while the Illinois River mainstem Long Range Outlook indicates around a 10 percent below normal chance for exceeding Moderate Flood levels. 

The  flood potential  is below normal in the Souris River basin. Dry fall conditions with soil moisture below normal at freeze-up are the contributing factors to the flood risk designation reflected in the Long Range Outlook.  Snow water equivalents for this time of year are also below normal across the basin. Dramatic temperature fluctuations, with brief periods of extreme cold followed by above-zero temperatures, have resulted in the consolidation of the snowpack and the formation of ice layers in much of the region. The presence of ice within the snowpack at the ground surface layer has the potential to impede soil infiltration capacity in the spring. Some frozen ground impacts are possible due to ice layers, deep frost, and multiple freeze/thaw cycles throughout the early winter.

The  flood potential  for the Red River basin is slightly below normal. Dry fall conditions with soil moisture below normal at freeze-up are the contributing factors to the flood risk designation reflected in the Long Range Outlook. Snow water equivalents for this time of year are also below normal across the basin. Similar to the Souris River basin, the winter has been characterized by multiple drastic temperature swings from well below zero temperature events, followed by days with temperatures above freezing. This has led to consolidation of snowpack and the formation of ice near the ground surface layer.

This area is carrying some of the deepest frost depths in the NCRFC area with amounts as deep as 50 inches. The deep frost and ice layers are especially of concern in the Red River basin, since this northern area historically tends to be one of the last areas to lose its frost. This increases the risk for intense surface runoff in rapid melt-off, rain-on-snow, and excessive rainfall scenarios during the winter to spring transition. This additional risk is not explicitly captured in the Long Range Outlooks. 

Lastly, the lack of snow cover has increased  ice development on rivers  The thicker ice conditions could increase the risk for larger break-up ice jams once widespread melt begins. Many rivers in this basin are currently simulating above average streamflow and are within a  flow regime  favorable for ice jam formation.

The  flood potential  for the Lake of the Woods drainage is below normal. NCRFC is now providing forecast services for three locations in the Lake of the Woods drainage. All three locations indicate less than a two percent chance of Significant Flooding based on the impacts and flood thresholds established with the  Duluth Weather Forecast Office . The below normal flood potential is being driven by the dry conditions that have been persistent across the region since August of last year. Snow water equivalent ranking for this time of year is now in the bottom 10th percentile. 

Compared to 2023, Devils Lake crested lower and a couple months later in 2024. However, the lake froze in place about a half foot higher than it was last year at this time. The latest level is 49.4’ (1449.4’). The Devils Lake basin was one area in the NCRFC service area that has been wetter than average. Precipitation from August 2024 to present was 100-120 percent of normal. Currently the snow water equivalent ranking is in the bottom 10th percentile.

With respect to the  Long Range Outlook , there is a 50 percent chance of the lake rising up to near 50.9’ (1450.9’), 25 percent chance of exceeding 51.3’ (1451.3’), and a 10 percent chance of exceeding 51.9’ (1451.9’). To put those values in perspective, the lake was around 52’ (1452’) in 2010; and the record level set in 2011 was 54.3’ (1454.3). Note: All elevation values given are based on NGVD29 datum for reference with impacts and historical crest on the NWS NWPS page. This Devils Lake outlook is valid for March 10, 2025 - September 30, 2025.

The  flood potential   for the Arrowhead (North Shore) and Upper Peninsula (South Shore) drainage is slightly below normal for this time of year. Going into freeze-up, the Lake Superior drainage on the U.S. side was in moderate to severe  drought . The snow water equivalent (SWE) ranking for the North Shore basins is between the 20th and 50th percentile; while the South Shore is experiencing a little wetter than average winter with SWE rankings between the 50th and 90th percentile.

The  flood potential  for the Lake Michigan drainage basins is largely normal to below normal.  The soil moisture and snow pack conditions for Lake Michigan drainage are similar to that of Lake Superior. Much of the drainage area was in moderate to severe  drought  going into freeze-up. There is negligible snowpack remaining for eastern Wisconsin. The western Lake Michigan coastline, where lake-effect snow is common, also has negligible snowpack in the central region of the lake; however, the northern portion of the lake has snow water equivalent rankings in the 40th to 70th percentile range.  The Lake Michigan drainage is expected to be snow free by next week.

The  flood potential  for the Lake Huron drainage basins is slightly below normal. The soil moisture conditions and latest winter snow pack amounts support the current Long Range Outlook. Going into freeze-up, the Lake Huron drainage was classified as abnormally dry to in severe drought by the  U.S. Drought Monitor . This region is nearly snow free at this time. 

This is the third and final outlook provided from mid-February through mid-March, to communicate hydrologic conditions across the region, and the associated potential for spring flooding.

The following dates are the 2025 Spring Outlook issuance dates for all NWS regions and NWS Headquarters. National Weather Service issues Spring Flood Outlook with probabilistic products on:

• Thursday, February 13, 2025
• Thursday, February 27, 2025
• Thursday, March 13, 2025

NOAA National Hydrologic Assessment will be published on:

• Thursday, March 20, 2025

The  North Central River Forecast Center  will continue to monitor the situation going forward.