2018 Spring Flood and Water Resource Outlook

Spring Flood and Water Resource Outlook

 

This Spring Flood and Water Resources Outlook is for the Quad Cities Hydrologic Service Area (HSA), which covers portions of eastern Iowa, northwest and west central Illinois, and extreme northeast Missouri. This includes the Mississippi River from above Dubuque, Iowa to below Gregory Landing, Missouri and its tributaries. The primary tributary river basins include the Maquoketa, Wapsipinicon, Cedar, Iowa, Skunk, and Des Moines Rivers in Iowa, the Fox River in Missouri, and the Pecatonica, Rock, Green, and La Moine Rivers in Illinois.

Probabalistic Hydrologic Outlook

Use the links below to find the Graphical Probabilities and the Numerical Probabilities respectively.

Graphical Hydrologic Outlooks Images below are examples which link to the Wapsipinicon River near DeWitt. Find all other locations in the Quad Cities Hydrologic Service Area in the drop down menu below.

Statistical Hydrologic Outlook

Select Location: Mississippi River at Dubuque L&D 11Mississippi River at DubuqueMississippi River at Bellvue L&D 12Mississippi River at Fulton L&D 13Mississippi River at CamancheMississippi River at Le Claire L&D 14Mississippi River at Rock Island L&D 15Mississippi River at Illinois City L&D 16Mississippi River at MuscatineMississippi River at New Boston L&D 17Mississippi River at KeithsburgMississippi River at Gladstone L&D 18Mississippi River at BurlingtonMississippi River at Keokuk L&D 19Mississippi River at Gregory LandingMaquoketa River at ManchesterMaquoketa River at MaquoketaWapsipinicon River at IndependenceWapsipinicon River at AnamosaWapsipinicon River at De WittCedar River at VintonCedar River at Cedar RapidsCedar River at ConesvilleIowa River at MarengoIowa River at Iowa CityIowa River at Lone TreeIowa River at Columbus JunctionIowa River at WapelloIowa River at OakvilleEnglish River at KalonaSkunk River at SigourneySkunk River at AugustaDes Moines River at KeosauquaDes Moines River at St FrancisvilleFox River at WaylandPecatonica River at FreeportRock River at ComoRock River at JoslinRock River at MolineGreen River at GeneseoLa Moine River at Colmar   Go

 

Flood Outlook Summary

The risk for flooding this spring, beyond the middle of March, is above normal for the Mississippi River, near to above normal for rivers in Illinois, and near normal for rivers in Iowa and Missouri.

Main Points:

• The northern part of the Mississippi River basin is vulnerable to extreme runoff given a quick snowmelt and heavy rainfall, which could cause flooding along the entirety of the Mississippi River this spring.
• Wet soils and high streamflows following heavy rains in February will keep rivers in Illinois susceptible to additional flooding this spring.
• While flooding due to snowmelt alone remains possible along the Mississippi River, heavy rains will be needed for flooding this spring along local rivers, and would contribute to more severe flooding on the Mississippi River.

NOTE: A heightened risk for flooding is not an indicator of severity. The highest probabilities this season are for minor flooding.

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Current and Forecast River Conditions - Advanced Hydrologic Prediction Service (AHPS)

Observed Conditions	Forecast Conditions	Long-Range Outlooks

 

Flood Category definitions:

• Minor Flooding - minimal or no property damage, but possibly some public threat or inconvenience.
• Moderate Flooding - some inundation of structures and roads near streams. Some evacuations of people and/or transfer of property to higher elevations may be necessary.
• Major Flooding - extensive inundation of structures and both primary and secondary roads. Usually significant evacuations of people and/or transfer of property to higher elevations.  

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Many factors are considered when determining the overall flood risk for the season, with the combination of these influences factoring into the final determination. These factors are discussed in detail below.

Seasonal Precipitation

After well above normal precipitation during the second part of February, total precipitation for the winter season averages out at near normal amounts. The wettest conditions occurred over Illinois, with amounts in February totaling 3 to 5 inches. Lower amounts were observed over the Iowa and Missouri portions of the area.

Below you will find graphics of the precipitation accumulated this winter season (left) and how this amount of moisture compares to normal in percentage (right). These graphics are courtesy of the Midwest Regional Climate Center.

Current Streamflow

Streamflows are running at near to above normal levels. This leads to a higher chance for flooding as lesser amounts of runoff are needed to rise the rivers to flood stage.

 

Iowa	Illinois	Missouri

Images courtesy of the USGS

 

Soil Conditions

After the ground thawed the last week of February, ponded water soaked into the ground. This has allowed moistening of the soils. Across Iowa and Missouri, where the soils are less saturated, more water can be absorbed leading to lowered chances for flooding when compared to locations in Illinois, where soils are more saturated.

Image courtesy of the NWS Climate Prediction Center

 

Snow Cover and Liquid Water Content

Snow fell across the northern parts of the Upper Mississippi River basin, which added to the winter snowpack. The snow cover resides north of a line from far north central Iowa to the Green Bay, WI area. Liquid water content in the snowpack is measuring at 1 to 4 inches, with some localized areas of 4 to 6 inches in northern Wisconsin.

Images courtesy of the National Operational Hydrologic Remote Sensing Center (NOHRSC)

 

Frost Depth

The ground has thawed across much of the local area, which will lower flooding potential on area rivers given unsaturated soils. However, the upper portions of the Mississippi River basin remain frozen to depths of 1 to 4 feet. Conditions that would cause higher chances for flooding on the Mississippi river would be a quick melt of the snowpack, heavy rain, or a combination of heavy rain and a melting snowpack, as frozen ground will contribute to escalated runoff amounts.

Frost Depths - North Central River Forecast Center

Ice Jam Flooding

River ice has lessened considerably through the end of February due to the warm temperatures as well as high streamflows pushing ice out of the rivers. Going through March, warming temperatures will lead to the continued melting of river ice, which will lower the chances for ice jams and subsequent flooding. However, any rivers that still have ice cover will still be vulnerable to ice jam flooding.

Drought

According to the U.S. Drought Monitor, Abnormally Dry (D0) and Moderate Drought (D1) conditions are ongoing from Missouri into southeast Iowa. conditions have improved because of the rainfall the end of February.

Image courtesy of the US Drought Monitor

 

Precipitation and Temperature Outlooks

The following are weather outlooks for 8-14 day time period and for the March, April, May period.

8 to 14 day Temperature Outlook	8 to 14 day Precipitation Outlook

 

Three Month Temperature Outlook (March, April, May)	Three Month Precipitation Outlook (March, April, May)

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River and streamflow information:

• National Weather Service: water.weather.gov
• US Geological Survey: water.usgs.gov/waterwatch
• Corps of Engineers: rivergages.com 

Flood safety and flood insurance information:

• NWS Flood Safety: www.floodsafety.noaa.gov
• National Flood Insurance Program: www.floodsmart.gov

Precipitation, temperature, and soil moisture information:

• National Operational Hydrologic Remote Sensing Center: www.nohrsc.noaa.gov
• NWS Graphical 7-Day Forecast: https://graphical.weather.gov/sectors/uppermissvly.php
• NWS Climate Prediction Center: www.cpc.ncep.noaa.gov
• US Drought Portal: www.drought.gov 

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Questions or Comments

If you have questions or comments about this spring flood and water resource outlook please contact:

Jessica Brooks
Service Hydrologist
National Weather Service
9050 Harrison St
Davenport, IA 52806
563-391-7094 ext 493
Email: jessica.brooks@noaa.gov