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Every spring the National Weather Service (NWS) prepares a series of flood outlooks for the potential of river flooding as a result of snow pack melt.
Each outlook takes into account antecedent conditions and current snowpack levels to anticipate the overall flood risk. The rate and timing of melt, in addition to future precipitation, can alter conditions as well.
These outlooks contain information about the potential for flooding throughout the spring months. The information can help decision makers and those with river interests prepare, in order to protect life and property.
Planned Spring Snowmelt Flood Outlook Release Dates:
Spring Flood Outlook Presentation
The overall risk for flooding this spring is below normal, and virtually entirely dependent on future precipitation.
This information is the first of three planned spring flood and water resources outlooks providing spring snowmelt and flood potential information for this upcoming spring. The information that goes into this outlook was collected from a number of National Weather Service partners including the United States Geological Survey, US Army Corps of Engineers, Midwestern Regional Climate Center, US Drought Monitor, Climate Prediction Center, and NOAA’s Office of Water Prediction.
This outlook is a summary of the past and present basin conditions for parts of southeast Minnesota, northeast Iowa, and southwest into central Wisconsin.
...FLOOD POTENTIAL SUMMARY HIGHLIGHTS…
The overall flood risk for the Upper Mississippi River Basin is BELOW NORMAL.
...Past Precipitation…
During autumn 2023, it was mainly drier than normal (up to 4” drier than normal) across northeast Iowa, southeast Minnesota, and south of Interstate 90 in western Wisconsin. Meanwhile, it was wetter-than-normal (1 to 6” above normal) north of Interstate 90. Much of this precipitation fell (2 to 7”) from October 23 through October 25.
As typical during El Niño, much of the Upper Mississippi River Valley was drier than normal. Precipitation deficits ranged from near normal to 2” drier than normal north of a Charles City, IA to Black River Falls, WI line. Precipitation surpluses were up 1” south of this aforementioned line.
This precipitation during autumn and winter was not enough to alleviate the large precipitation deficits that had increased during the 2023 growing season (since April 1). Precipitation departures ranged from 8 to just over 19" along and south of Interstate 90. Due to this, these areas are still experiencing moderate (D1) to extreme drought (D3). The last time that it has been this dry going into a spring was back in 2004. In 2004, nearly 60% of the La Crosse Hydrologic Service Area (HSA) was in severe (D2) drought.
...River Conditions...
Overall, the amount of water currently moving through our rivers is near the long-term average. Due to a December rain and an earlier-than-normal snow melt, a few rivers are flowing above normal, but that’s simply an artifact of rivers normally not adding additional inflow this early in the year.
...Soil Moisture and Frost Depths...
Last September, most of the region was in a drought status. Since then, parts of the area have experienced heavier rains in October and again in December. While drought conditions have improved for some, significant areas of drought still prevail, especially across parts of Iowa.
Due to the abnormally warm temperatures this winter, frost depths are well below normal for this time of year. Most areas along and south of Interstate 90 do not have any frost.
...Snow Cover and Liquid Water Content...
A strong El-Niño this winter has played a big role in one of the warmest winters on record across the Upper Mississippi River Basin. Any snow that the region has received has largely melted already, leaving little to no snowpack left for a spring melt runoff.
...River Ice Conditions...
The near record-setting warmth this winter has led to well-below-normal river ice conditions across the region.
…Weather Outlook…
The above conditions can and often change. The biggest factor affecting spring flood risks is the weather conditions during the sensitive period of melting snow. This year, without the presence of a snowpack, future precipitation is the main driver of any flood risk moving forward.
For March, NOAA’s Climate Prediction Center (CPC) has a slight shift in the probabilities toward warmer than normal along and north of Interstate 94. Elsewhere, there are equal chances of warmer-, near-, and colder-than-normal. There are equal chances of wetter-, near-, and drier-than-normal. Normal temperatures in March range from 27 to 30°F north of Wisconsin Highway 29 and from 30 to 35°F elsewhere. March precipitation normals range from 1.6 to 2" inches along and north of Interstate 94, and from 2 to 2.4" across the remainder of the area.
During the 7 strong El Niños since 1949-50, 4 have been among the warmest third, and the remaining 3 were near normal. Precipitation was highly variable with 4 being among the wettest third, 2 among the driest third, and 1 near normal. Snowfall was also highly variable with 4 among the third least, 2 among the snowiest third, and 1 near normal.
For spring, NOAA’s Climate Prediction Center currently shows around a 40 percent chance for above-normal temperatures through March, April, and May. There are equal chances for wetter, near, and drier-than-normal precipitation this spring. The normal precipitation range during these 3 months ranges from roughly 8 to 11 inches of precipitation.
Spring Flood Outlook Presentation
The overall risk for flooding this spring is below normal, and virtually entirely dependent on future precipitation.
...SECOND 2024 SPRING FLOOD AND WATER RESOURCES OUTLOOK...
The overall risk for flooding this spring is below normal along the mainstem of the Mississippi River and its associated tributaries across southeast Minnesota, northeast Iowa, and southwest Wisconsin.
The final planned spring flood outlook release will be on Thursday, March 14th, 2024.
This information is the second of three planned spring flood and water resources outlooks providing spring snowmelt and flood potential information for this upcoming spring. The information that goes into this outlook was collected from a number of National Weather Service partners including the United States Geological Survey, US Army Corps of Engineers, Midwestern Regional Climate Center, US Drought Monitor, Climate Prediction Center, and NOAA’s Office of Water Prediction.
This outlook is a summary of the past and present basin conditions for parts of southeast Minnesota, northeast Iowa, and southwest into central Wisconsin.
...FLOOD POTENTIAL SUMMARY HIGHLIGHTS…
The overall flood risk for the Upper Mississippi River Basin is BELOW NORMAL.
...Past Precipitation…
During autumn 2023, it was mainly drier than normal (up to 4” drier than normal) across northeast Iowa, southeast Minnesota, and south of Interstate 90 in western Wisconsin. Meanwhile, it was wetter-than-normal (1 to 6” above normal) north of Interstate 90. Much of this precipitation fell (2 to 7”) from October 23 through October 25.
As typical during El Niño, much of the Upper Mississippi River Valley was drier than normal during meteorological winter. Precipitation deficits ranged from near normal to 2” drier than normal north of a Charles City, IA to Black River Falls, WI line. Precipitation surpluses were up 1” in southwest Wisconsin.
This precipitation during autumn and winter was not enough to alleviate the large precipitation deficits that had increased during the 2023 growing season (since April 1). Precipitation departures ranged from 8 to just over 19" along and south of Interstate 90. The driest areas were in northeast Iowa. Due to this, these areas are still experiencing moderate (D1) to extreme drought (D3). The last time that it has been this dry going into a spring was back in 2004. During that year, nearly 60% of the La Crosse Hydrologic Service Area (HSA) was in severe (D2) drought.
Since the last outlook, we have not seen enough additional precipitation to tip the flood probability scales the other direction. Across the region, precipitation values for the past two weeks have ranged from around 0.25 inches up to 0.75 inches near the Twin Cities in Minnesota.
...River Conditions...
Overall, the amount of water currently moving through our rivers is near the long-term average. Due to a December rain and an earlier-than-normal snow melt, a few rivers are flowing above normal, but that’s simply an artifact of rivers normally not adding additional inflow this early in the year.
...Soil Moisture and Frost Depths...
Last September, most of the region was in a drought status. Since then, parts of the area have experienced heavier rains in October and again in December. While drought conditions have improved for some, significant areas of drought still prevail, especially across parts of Iowa.
Due to the abnormally warm temperatures this winter, frost depths are well below normal for this time of year. Our entire region is free of frost and any future precipitation will be able to absorb into the soils freely.
...Snow Cover and Liquid Water Content...
A strong El-Niño this winter has played a big role in one of the warmest winters on record across the Upper Mississippi River Basin. Any snow that the region has received has largely melted already, leaving little to no snowpack left for a spring melt runoff.
...River Ice Conditions...
The near record-setting warmth this winter has led to well-below-normal river ice conditions across the region.
…Weather Outlook…
The above conditions can and often change. The biggest factor affecting spring flood risks is the weather conditions during the sensitive period of melting snow. This year, without the presence of a snowpack, future precipitation is the main driver of any flood risk moving forward.
For March, NOAA’s Climate Prediction Center (CPC) has a slight shift in the probabilities toward warmer than normal along and north of Interstate 94. Elsewhere, there are equal chances of warmer-, near-, and colder-than-normal. There are equal chances of wetter-, near-, and drier-than-normal. Normal temperatures in March range from 27 to 30°F north of Wisconsin Highway 29 and from 30 to 35°F elsewhere. March precipitation normals range from 1.6 to 2" inches along and north of Interstate 94, and from 2 to 2.4" across the remainder of the area. This forecast will be updated on Friday, March 1.
During the 7 strong El Niños since 1949-50, 4 have been among the warmest third, and the remaining 3 were near normal. Precipitation was highly variable with 4 being among the wettest third, 2 among the driest third, and 1 near normal. Snowfall was also highly variable with 4 among the third least, 2 among the snowiest third, and 1 near normal.
For spring, NOAA’s Climate Prediction Center currently shows around a 40 percent chance for above-normal temperatures through March, April, and May. There are equal chances for wetter, near, and drier-than-normal precipitation this spring. The normal precipitation range during these 3 months ranges from roughly 8 to 11 inches of precipitation.
Spring Flood Outlook Presentation
The overall risk for flooding this spring is below normal, and virtually entirely dependent on future precipitation.
...THIRD AND FINAL 2024 SPRING FLOOD AND WATER RESOURCES OUTLOOK...
The overall risk for flooding this spring is below normal along the mainstem of the Mississippi River and its associated tributaries across southeast Minnesota, northeast Iowa, and southwest Wisconsin.
This is the final planned spring flood outlook for 2024.
This information is the last of three planned spring flood and water resources outlooks providing spring snowmelt and flood potential information for this upcoming spring. The information that goes into this outlook was collected from a number of National Weather Service partners including the United States Geological Survey, US Army Corps of Engineers, Midwestern Regional Climate Center, US Drought Monitor, Climate Prediction Center, and NOAA’s Office of Water Prediction.
This outlook is a summary of the past and present basin conditions for parts of southeast Minnesota, northeast Iowa, and southwest into central Wisconsin.
...FLOOD POTENTIAL SUMMARY HIGHLIGHTS…
The overall flood risk for the Upper Mississippi River Basin is BELOW NORMAL.
...Past Precipitation…
During autumn 2023, it was mainly drier than normal (up to 4” drier than normal) across northeast Iowa, southeast Minnesota, and south of Interstate 90 in western Wisconsin. Meanwhile, it was wetter-than-normal (1 to 6” above normal) north of Interstate 90. Much of this precipitation fell (2 to 7”) from October 23 through October 25.
As typical during El Niño, much of the Upper Mississippi River Valley was drier than normal during meteorological winter. Outside of a narrow line through the Trempealeau and Black River basins, the entire region received near to below normal precipitation.
Precipitation during autumn and winter was not enough to alleviate the large precipitation deficits that had increased during the 2023 growing season (since April 1). Precipitation departures ranged from 8 to just over 19" along and south of Interstate 90. The driest areas were in northeast Iowa. Due to this, these areas are still experiencing moderate (D1) to extreme drought (D3). The last time that it has been this dry going into a spring was back in 2004. During that year, nearly 60% of the La Crosse Hydrologic Service Area (HSA) was in severe (D2) drought. Since the last outlook, we have not seen enough additional precipitation to tip the flood probability scales the other direction. In fact, we have seen drought expand across the local La Crosse Hydrologic Service area, a total of 8.38% more of our area is now in drought. This trend was also seen upstream of our area across much of central Minnesota. Across the region, precipitation values for the past two weeks have ranged from no precipitation near the Twin Cities up to around 0.75 inches along a line from Decorah, Iowa to Wausau, Wisconsin.
...River Conditions...
Overall, the amount of water currently moving through our rivers is below long-term average. Lack of snowmelt runoff this year, due to a well-below normal seasonal snowfall, is the main contributor.
...Soil Moisture and Frost Depths...
Last September, most of the region was in a drought status. Since then, despite parts of the area experiencing heavier rains in October and again in December, drought has expanded across the region. Due to the drought, soil moisture across the region is well below normal.
Due to the abnormally warm temperatures this winter, frost depths are well below normal for this time of year. Our entire region is free of frost and any future precipitation will be able to absorb into the soils freely.
...Snow Cover and Liquid Water Content...
A strong El-Niño this past winter played a big role in one of the warmest winters on record across the Upper Mississippi River Basin. Any snow that the region received this winter has largely melted already, leaving little to no snowpack left for a spring melt runoff.
...River Ice Conditions...
The near record-setting warmth this winter has led to rivers being virtually ice free across our region.
…Weather Outlook…
The above conditions can and often change. The biggest factor affecting spring flood risks is the weather conditions during the sensitive period of melting snow. This year, without the presence of a snowpack, future precipitation is the main (only) driver of any flood risk moving forward.
For March, NOAA’s Climate Prediction Center (CPC) latest update on February 29th has shifted the probabilities toward warmer than normal across much of the region. There are equal chances of wetter-, near-, and drier-than-normal. Normal temperatures in March range from 27 to 30°F north of Wisconsin Highway 29 and from 30 to 35°F elsewhere. March precipitation normals range from 1.6 to 2" inches along and north of Interstate 94, and from 2 to 2.4" across the remainder of the area.
During the 7 strong El Niños since 1949-50, 4 have been among the warmest third, and the remaining 3 were near normal. Precipitation was highly variable with 4 being among the wettest third, 2 among the driest third, and 1 near normal. Snowfall was also highly variable with 4 among the third least, 2 among the snowiest third, and 1 near normal.
For spring, NOAA’s Climate Prediction Center currently shows around a 40 percent chance for above-normal temperatures through March, April, and May. There are equal chances for wetter, near, and drier-than-normal precipitation this spring. The normal precipitation range during these 3 months ranges from roughly 8 to 11 inches of precipitation. This outlook will be updated on March 15th.
References
River Levels
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