Further north, these values increase to around 200-300% of normal, especially from south central Minnesota into northwest Wisconsin. Analysis from the Midwest Regional Climate Center (MRCC) shows locations mainly north of Hwy 30 in eastern Iowa and northwest Illinois around 100-175% of normal during the period. Precipitation from the winter into early Spring continues to average near to well above normal for all of the NWS Quad Cities Hydrologic Service Area (HSA), as well as locations to the north. These factors are discussed in detail below. Many factors are have been considered when determining the overall flood risk for the Spring, with the combination of these influences factoring into the final determination. Images below are examples which link to the Wapsipinicon River near DeWitt.įind all other locations in the Quad Cities Hydrologic Service Area in the drop down menu below. Use the links below to find the Graphical Probabilities and the Numerical Probabilities, respectively. These factors are discussed in detail in the next few tabs and also in the Statistical Hydrological Outlook linked below. The combination of these influences factor into the final determination. Many factors are considered when determining the overall flood risk for the upcoming spring season. * Lower than expected precipitation over the past 2 weeks have caused stream flows in the upper Mississippi watershed to currently be running near normal, meaning there is some added capacity to handle heavy spring rains than there was 2 weeks ago. We will continue to monitor soil moisture conditions as they have continued to moisten over the past months. * Widespread above normal soil moisture levels in the local area reduces the capacity of the soils to soak in spring precipitation and does less to mitigate the near term flood risk as well as slightly increase the risk for prolonged flooding. A slow, steady melt would decrease that threat. A rapid snowmelt occurring over still frozen ground would increase the likelihood of high impact flooding on the Mississippi River this spring. However, the snow water equivalent in the headwaters of the upper Mississippi River basin are well above normal and increased again from the previous outlook. * Snow cover and snow water equivalent were well below normal across much of the local area, which decreased the overall flood threat. In particular, we will be monitoring the temperature and snowmelt trends in the Mississippi River headwaters and whether there are any large rain on snow events. The severity of any flooding will be determined by the key factors mentioned above. * Even though the overall risk of spring flooding is well above average on the Mississippi River, this does not guarantee that high impact flooding will occur. 3) Above average winter precipitation levels and above normal river levels. 2) A general lack of deep, hard frozen ground across the upper Mississippi River Basin. Some factors contributing to the current risk levels include: 1) Lack of deep and widespread snowpack in the local area, while the upper reaches of the Mississippi River basin has above average snowpack. Additional precipitation events and the rate of snowmelt in the upper Mississippi basin will be the main factors determining the severity of the flooding this spring. Snow water equivalent is much higher than average in the upper portion of the Mississippi basin and has continued to grow since the first outlook. For local tributaries the risk is also increasing due to moistening soils and higher current streamflows. The flood risk has increased during the past 2 weeks due to additional snowfall in the upper portion of the Mississippi basin. The spring flood risk is well above normal for the Mississippi River, and near normal but increasing for local tributary rivers across the NWS Quad Cities Hydrologic Service Area. This will be the last Flood Outlook issued, however the NWS Quad Cities will continue to provide regular updates throughout the lead up to and during the Spring Flood Season.The flood risk has decreased slightly during the past 2 weeks due to drier than expected conditions in the local area.Near normal spring flood risk for local tributary rivers.Well above normal spring flood risk for the Mississippi River.
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