Flood Potential Outlook
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
286
FGUS73 KDVN 271807
ESFDVN
IAC011-019-031-045-055-057-061-087-095-097-101-103-105-107-111-113-
115-139-163-177-183-ILC011-015-067-071-073-085-109-131-155-161-177-
187-195-MOC045-199-151800-
Probabilistic Hydrologic Outlook
National Weather Service Quad Cities IA IL
1207 PM CST Thu Feb 27 2025
...2025 Spring Flood and Water Resources Outlook 2...
.Introduction:
... Below Normal Flood Risk This Spring...
This is the second of the three planned Spring Flood and Water
Resource Outlooks for 2025 for the Quad Cities Hydrologic Service
Area (HSA), which covers portions of easternIowa, northwest and
west central Illinois, and extreme northeast Missouri. Rivers
included in this outlook are the Mississippi River and its
tributaries from just north of Dubuque, Iowa to south of Gregory
Landing, Missouri. The primary tributary systems include the
Maquoketa, Wapsipinicon, Cedar, English, Iowa, Skunk, North Skunk,
and Des Moines Rivers in Iowa; the Fox River in Missouri; and the
Pecatonica, Rock, Green, andthe La Moine Rivers in Illinois. This
outlook is for the time period from March through May.
.Flood Outlook Overview...
The spring flood risk is below normal for the Mississippi River, and
near to below normal for local tributary rivers across the NWS Quad
Cities HSA.
Some factors contributing to the current risk levels include:
1. Minimal to no snow and below normal precipitation throughout the
local area and the headwater areas in Minnesota and Wisconsin will
result in a low-end flood risk at this time, especially along the
Mississippi River.
2. Below normal soil moisture levels in the local area will provide
more potential storage for spring rains, especially when we thaw the
frozen soils. We also continue to see these soils dry more, resulting
in more room for water infiltration.
3. Deep frozen soils remain, especially near the headwaters of the
Mississippi River. However, given the ongoing stretch of above
normal temperatures, we have started to see the top layer of soil
thaw a bit. Further thaw will allow for more infiltration into the
soil. For those areas that continue to see a frozen top layer of
soil, little/no infiltration will be possible until thaw occurs.
4. Most streams throughout the local forecast area continue to see
the decreasing trend in streamflows, with most below to well below
normal.
Through the spring, impacts from these factors are expected
to change. One of the biggest factors that will drive any flood
threat this spring will be the spring precipitation that we receive,
whether it be from rain or snow. This, combined with any remaining
frozen ground may lead to issues down the road. Please continue to
monitor for any changes through the coming weeks.
.Key Takeaways...
* Even though the overall risk of spring flooding is below normal in
the NWS Quad Cities HSA, this does not guarantee that high impact
flooding will not occur. The severity of any flooding will be
determined primarily by changes in the key factors mentioned
above. In addition, we will be monitoring the outlooks for spring
precipitation to see if that could become a contributing factor
this year.
* Throughout the winter, precipitation both locally and regionally
remained below normal. This is especially true when it comes to
snowpack, or the lack thereof. Currently, the only snow remaining
resides in the northern half of Minnesota, with no snow expected
over the next week locally. An active weather pattern next week
will introduce more precipitation to the region, especially the
Upper Mississippi River Valley. A system is looking to impact the
region next week, bringing widespread moderate precipitation.
Impacts from this look to be minimal at this time, given the
conditions bulleted above. Rather, we can expect within bank rises
at this time. Although, given the ongoing drought and below to
well below normal streamflows, there remains plenty of room in
local streams, allowing for some give when it comes to increasing
precipitation. Current outlooks show the likelihood of Major
Flooding on the Mississippi River being low at this time (<5-10%
chance), but is subject to change.
* Widespread below normal soil moisture levels in the local area
increase the capacity of the soils to soak in precipitation and
will mitigate the near term flood risk, as well as decrease the
risk for prolonged flooding, especially once we thaw the frozen
soils.
Many factors are considered when determining the overall flood risk
for the upcoming spring season. A combination of these are factored
into the final threat categorization. These factors are discussed in
detail below, and are categorized as an increased, neutral, or a
decreased contributor to potential spring flooding.
.Seasonal Precipitation:
Local Rivers - Neutral to Decreased Threat
Mississippi River - Neutral to Decreased Threat
Precipitation in eastern Iowa, northwest Illinois, and northeast
Missouri has been below normalthis winter. With that, much of the
HSA, especially eastern Iowa and northwest Illinois, remains
Abnormally Dry or in a Moderate Drought due to below normal
precipitation observed since the fall months in 2024. This is also
reflected in soil moisture levels, which remain below normal. North
of the area, precipitation in the upper Mississippi River Basin this
winter has averaged below normal, aside from parts of far northern
Minnesota, which are slightly above normal.
Latest outlooks from the Climate Prediction Center (CPC) favor near
normal precipitation through the first half of March for all of the
Upper Mississippi River Basin, with above normal precipitation
favored for the month. Thus, guidance is highlighting the potential
for an active month of weather. With dry soils and ongoing drought,
any further precipitation should be allowed to infiltrate into the
ground, especially with the recent warm-up decreasing local frost
depths. Although, for areas where frozen soils remain, much of
the late winter and early spring precipitation will translate to
runoff, rather than easily infiltrate.
While current contributions from precipitation yield minimal impacts
on local flooding, an increasingly active pattern and storm track
over the next week are favorable for continued widespread
precipitation. This currently seems to favor within bank rises on
local streams, rather than having much of an impact of the flood
threat. Although, we will continue to monitor for any further changes
over the coming weeks.
..Snow Cover and Liquid Water Content:
Local Rivers - Neutral to Decreased Threat
Mississippi River - Neutral to Decreased Threat
Even with the latest snowfall and snow melt, low snow water
equivalent yielded little impact to the spring flood outlook. In
fact, after the melt, rivers continued to trend below normal for
streamflows. Thus, it will take a lot more heavy/wet snow to fall to
impact the flood outlook. While the CPC favors near normal
precipitation over the next two weeks, the overall outlook for the
month favors above normal precipitation. If we see heavy snow in the
local area or near the headwaters of the Mississippi River, then we
may see an impact. Although, we are not seeing any signals pointing
towards that right now. Thus, seasonal snowfall and its respective
liquid equivalent currently has a neutral to decreased impact on the
flood threat this spring.
.Soil Conditions:
Local Rivers - Neutral to Decreased Threat
Mississippi River - Neutral to Decreased Threat
Given the continuation of below normal precipitation since the fall,
soil moisture levels remain below normal. Latest analysis from the
Climate Prediction Center shows soil moisture ranking profiles
around 10-40% for the majority of the HSA, with near normal soil
conditions as we head towards the Mississippi headwaters. We
continue to see widespread Abnormally Dry to Moderate Drought
conditions through the Upper Mississippi River Valley. Considering
these factors, they favor a neutral to decreased threat for spring
flooding, as drier soils will be better suited to soak in heavier
rains once we lose the frost.
.Frost Depth:
Local Rivers - Neutral Threat
Mississippi River - Neutral Threat
The ground remains frozen throughout the Upper Mississippi River
Valley, especially deep in some areas. Although, recent temperature
trends have resulted in some thawing of the top layers of the soil.
Locally, we are seeing frost depth between 5-20 inches, with those
near the headwaters of the Mississippi River observing 20-40 inches
of
frost depth. Locally, frost depth hasn`t changed much over the last
two weeks, but we still have about an inch or more of thawed ground
on the top layer. Any frost depth can become problematic with
further precipitation this spring, prior to more thaw, as much of
the precipitation will fall as runoff rather than infiltrate easily
into the soil.
.River Conditions:
Local Rivers - Neutral to Decreased Threat
Mississippi River - Neutral to Decreased Threat
Streamflow analysis from the United States Geological Survey (USGS)
indicates the majority of the Upper Mississippi River watershed and
tributary streamflows are below normal. Locally, we have seen
streamflows continuing to trend below to well below normal levels.
This trend has been noted over the last two weeks, with little
precipitation being seen. Streamflows that are below normal levels
would have more capacity to hold runoff from heavy spring rains.
.Ice Jam Flooding:
Local Rivers - Neutral Threat for Breakup Jams
Mississippi River - Neutral Threat for Breakup Jams
Temperatures have been quite variable this winter, with stretches of
cold resulting in plenty of river ice. Although, there have been
bouts of above normal temperatures that have allowed for some of
this ice to melt and/or breakup. We are currently in the middle of
another warm stretch, which will allow for some river ice to melt or
break up. Current observations are indicating a low-medium threat
for break up ice jams, but fortunately we are lacking any heavy rain
at the moment. This should mean that the ice can gradually
melt/break up without many impacts. Will continue to message a
Neutral to Decreased Threat for ice jam flooding this spring,
focusing on the main threat being from a breakup jam.
.Weather/Climate Outlooks:
Local Rivers - Decreased Threat
Mississippi River - Decreased Threat
While active weather patterns are typical of the spring months, this
could lead to variations of warmer and colder temperatures, where
the risk for flooding will be determined by the tracks of individual
and multiple storm systems that could bring heavy rain or snow to
parts of the region.
According to the latest outlooks from the Climate Prediction Center,
probabilities are leaning toward above normal temperatures for much
of the region as we head into the first two weeks of March, with a
signal for above normal precipitation during the same timeframe.
The outlook for mid March through April is leaning towards near
normal temperatures for much of the region and above normal
precipitation.
.Summary:
The spring flood risk is below normal for the Mississippi River, and
near to below normal for local tributary rivers across the NWS Quad
Cities Hydrologic Service Area.Variable temperatures through the
winter have led to ice formation, along with some ice melt/breakup.
Snowfall has been well below normal for much of the winter, with an
uptick seen in mid February. Since then, we have remained relatively
dry and mild, with temperatures well above seasonal norms. Thus, we
have started to see soils drying out again, as well as some thawing
of the deep frozen grounds. The threat for ice jam flooding is
neutral at this point, but will be dependent on how rapidly the
current ice melts/breaks up. Some factors contributing to the current
risk levels include: 1) The general lack of precipitation this
winter, keeping us below normal, 2) Deep, frozen grounds across the
upper Mississippi River Basin will prevent much infiltration until
thawed, and 3) Streamflows trending below to well below normal, as
well as below normal soil moisture levels.
...Advanced Hydrologic Prediction Service Probabilistic Outlook...
This outlook provides long-range probabilistic river outlooks for
river basins in the NWS Quad Cities service area. This outlook is
divided into three parts, the first part for the probabilities of
minor, moderate and major flooding, the second part for high water
and the final part for low water.
In Table 1 below, the current (CS) and historical (HS) or normal
probabilities of exceeding minor, moderate and major flood stages
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: 03/03/2025 - 06/01/2025
: 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
-------- ----- ----- ----- : --- --- --- --- --- ---
:Mississippi River
Dubuque LD11 16.0 17.0 20.5 : 15 48 10 39 <5 12
Dubuque 17.0 18.0 21.5 : 19 53 14 47 <5 16
Bellevue LD12 17.0 18.0 20.0 : 9 37 <5 32 <5 12
Fulton LD13 16.0 18.0 20.0 : 16 53 7 35 <5 15
Camanche 17.0 18.5 20.5 : 14 47 7 35 <5 15
Le Claire LD14 11.0 12.0 13.5 : 16 53 10 37 <5 22
Rock Island LD15 15.0 16.0 18.0 : 20 59 14 53 <5 27
Ill. City LD16 15.0 16.0 18.0 : 20 59 13 48 6 27
Muscatine 16.0 18.0 20.0 : 23 62 13 48 6 27
New Boston LD17 15.0 16.5 18.5 : 31 64 15 54 8 32
Keithsburg 14.0 15.5 17.0 : 30 64 15 52 7 28
Gladstone LD18 10.0 12.0 14.0 : 32 65 14 49 <5 25
Burlington 15.0 16.5 18.0 : 28 64 14 49 6 30
Keokuk LD19 16.0 17.5 19.0 : 10 33 5 24 <5 12
Gregory Landing 15.0 18.0 25.0 : 31 65 12 43 <5 <5
:Maquoketa River
Manchester Hwy 20 14.0 17.0 20.0 : 16 22 11 17 <5 7
Maquoketa 24.0 26.0 28.5 : <5 15 <5 11 <5 6
:Wapsipinicon River
Independence 12.0 13.0 15.0 : 7 10 7 7 <5 <5
Anamosa Shaw Rd 14.5 18.0 21.5 : 16 26 7 13 <5 <5
De Witt 4S 11.0 11.5 12.5 : 59 72 47 65 27 42
:North Skunk River
Sigourney 16.0 18.0 21.0 : 45 55 25 41 7 13
:Skunk River
Augusta 15.0 17.0 20.0 : 31 44 20 32 8 16
:Cedar River
Vinton 15.0 18.0 19.0 : 7 19 <5 8 <5 5
Palo Blairs Ferry 12.5 15.5 17.0 : 9 26 <5 8 <5 <5
Cedar Rapids 12.0 14.0 16.0 : 9 35 5 18 <5 10
Cedar Bluff 16.0 20.0 26.0 : 10 33 <5 9 <5 <5
Conesville 13.0 15.0 16.5 : 24 54 5 15 <5 8
:Iowa River
Marengo 15.0 17.0 19.0 : 46 71 22 45 <5 7
Iowa City 23.5 24.5 26.0 : <5 <5 <5 <5 <5 <5
Lone Tree 16.0 18.5 22.0 : 23 34 6 8 <5 <5
Columbus Jct 23.0 25.0 26.5 : 5 20 <5 7 <5 <5
Wapello 21.0 25.0 27.5 : 25 54 <5 8 <5 <5
Oakville 11.0 15.0 20.0 : 20 44 <5 7 <5 <5
:English River
Kalona 14.0 16.0 18.0 : 45 50 21 34 8 15
:Des Moines River
Keosauqua 22.0 25.0 27.0 : 8 12 <5 <5 <5 <5
St Francisville 18.0 22.0 25.0 : 27 41 8 8 <5 <5
:Fox River
Wayland 15.0 18.0 20.0 : 24 24 10 13 <5 <5
:Pecatonica River
Freeport 13.0 14.0 16.0 : 20 39 7 24 <5 <5
:Rock River
Como 12.5 15.5 18.0 : 9 19 <5 10 <5 <5
Joslin 12.0 14.0 16.5 : 28 59 12 30 5 16
Moline 12.0 13.0 14.0 : 25 54 13 28 9 20
:Green River
Geneseo 15.0 16.5 18.0 : 12 24 8 13 <5 <5
:La Moine River
Colmar 20.0 22.0 24.0 : 50 61 37 42 15 20
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: 03/03/2025 - 06/01/2025
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Mississippi River
Dubuque LD11 7.1 8.3 9.6 12.0 14.1 16.9 18.4
Dubuque 9.5 10.5 11.5 13.8 16.0 18.7 20.1
Bellevue LD12 7.9 9.1 10.3 12.6 14.3 16.7 18.0
Fulton LD13 7.5 8.7 9.7 12.4 14.9 17.2 18.6
Camanche 10.2 11.1 11.8 13.5 15.5 17.7 19.1
Le Claire LD14 6.0 6.8 7.5 8.9 10.2 12.0 13.1
Rock Island LD15 7.7 9.4 10.4 12.3 14.5 17.0 17.9
Ill. City LD16 6.1 7.7 9.4 12.0 14.1 16.7 18.1
Muscatine 7.8 9.5 11.1 13.5 15.7 18.7 20.1
New Boston LD17 7.3 9.3 11.1 13.3 15.2 17.8 19.4
Keithsburg 8.8 9.5 11.2 12.3 14.6 16.8 17.4
Gladstone LD18 4.0 4.7 6.9 8.4 10.8 13.1 14.0
Burlington 10.1 10.6 12.2 13.4 15.4 17.6 18.3
Keokuk LD19 6.0 6.6 8.9 10.6 13.1 16.3 17.6
Gregory Landing 7.8 8.3 10.8 13.6 16.0 18.6 20.6
:Maquoketa River
Manchester Hwy 20 5.4 5.9 7.0 8.4 10.4 17.8 19.2
Maquoketa 11.5 12.1 12.9 14.6 16.4 21.6 22.9
:Wapsipinicon River
Independence 5.5 6.1 6.5 7.3 8.2 10.9 14.2
Anamosa Shaw Rd 5.9 7.7 8.2 10.5 12.5 16.5 19.4
De Witt 4S 7.5 8.7 10.0 11.4 12.6 13.4 13.7
:North Skunk River
Sigourney 4.9 9.3 13.0 15.2 18.1 20.0 21.6
:Skunk River
Augusta 2.8 5.4 8.6 12.9 15.7 19.4 24.3
:Cedar River
Vinton 3.5 4.1 5.9 9.0 11.3 13.6 16.3
Palo Blairs Ferry 3.2 4.1 5.5 8.0 9.8 11.8 13.9
Cedar Rapids 4.0 4.7 5.2 7.2 9.1 11.8 15.3
Cedar Bluff 5.3 6.5 8.4 10.6 12.5 15.9 18.7
Conesville 6.1 7.2 9.0 10.8 12.9 14.1 15.2
:Iowa River
Marengo 7.0 8.6 11.1 14.7 16.6 17.7 18.3
Iowa City 10.5 11.5 13.7 16.0 18.9 19.7 20.9
Lone Tree 6.0 8.2 10.8 12.8 15.6 17.7 19.1
Columbus Jct 10.1 12.5 14.4 16.2 19.4 22.3 23.5
Wapello 13.2 15.4 17.5 18.7 21.1 23.0 24.0
Oakville 2.7 4.4 6.4 7.7 10.2 12.2 13.3
:English River
Kalona 5.6 7.4 11.6 13.4 15.7 17.7 19.4
:Des Moines River
Keosauqua 11.5 12.8 16.7 18.2 19.8 21.4 24.0
St Francisville 8.2 9.9 14.8 16.5 18.4 20.9 24.1
:Fox River
Wayland 3.5 5.1 8.0 11.4 14.8 17.9 19.8
:Pecatonica River
Freeport 6.3 6.7 7.6 9.8 12.2 13.8 14.4
:Rock River
Como 4.3 4.9 5.5 7.4 9.1 11.7 13.9
Joslin 7.1 7.8 8.6 10.3 12.7 14.5 17.8
Moline 8.6 9.1 9.6 10.6 12.0 13.4 15.9
:Green River
Geneseo 3.6 4.8 7.2 10.2 12.7 15.7 17.2
:La Moine River
Colmar 6.7 8.9 13.4 19.9 23.0 24.7 26.1
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: 03/03/2025 - 06/01/2025
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Mississippi River
Dubuque LD11 39.1 38.9 35.4 31.9 27.8 24.6 22.0
Dubuque 39.1 38.9 35.4 31.9 27.8 24.6 22.0
Bellevue LD12 37.6 37.5 35.8 32.5 28.9 24.9 22.4
Fulton LD13 37.3 37.2 37.0 34.0 30.2 25.9 23.5
Camanche 37.3 37.2 37.0 34.0 30.2 25.9 23.5
Le Claire LD14 37.0 37.0 36.9 35.8 31.2 26.9 24.4
Rock Island LD15 40.3 40.3 40.2 40.1 34.9 30.0 28.1
Ill. City LD16 41.1 41.1 41.0 40.9 36.1 31.8 29.1
Muscatine 41.1 41.1 41.0 40.9 36.1 31.8 29.1
New Boston LD17 40.6 40.5 40.4 40.3 36.2 31.8 29.2
Keithsburg 45.2 45.0 45.0 44.9 39.0 35.5 30.8
Gladstone LD18 45.2 45.1 45.0 44.9 39.0 35.6 30.8
Burlington 45.3 45.2 45.1 45.0 39.1 35.6 30.8
Keokuk LD19 44.4 44.3 44.2 44.2 40.9 34.2 27.9
Gregory Landing 47.5 47.4 47.3 47.3 42.5 36.0 29.4
:Maquoketa River
Manchester Hwy 20 0.1 0.1 0.1 0.1 0.1 0.1 0.1
Maquoketa 0.7 0.7 0.6 0.5 0.5 0.4 0.3
:Wapsipinicon River
Independence 0.3 0.3 0.3 0.3 0.2 0.2 0.2
Anamosa Shaw Rd 0.6 0.6 0.5 0.5 0.4 0.4 0.3
De Witt 4S 1.1 1.1 1.0 0.9 0.8 0.6 0.6
:North Skunk River
Sigourney 0.1 0.1 0.1 0.1 0.1 0.0 0.0
:Skunk River
Augusta 1.1 1.0 0.8 0.7 0.5 0.3 0.2
:Cedar River
Vinton 1.3 1.3 1.2 1.1 0.9 0.8 0.7
Palo Blairs Ferry 1.5 1.4 1.3 1.2 1.0 0.9 0.7
Cedar Rapids 1.6 1.5 1.4 1.2 1.0 0.9 0.8
Cedar Bluff 1.8 1.7 1.6 1.4 1.2 1.0 0.8
Conesville 2.3 2.3 2.1 1.7 1.4 1.2 0.9
:Iowa River
Marengo 0.7 0.6 0.6 0.4 0.4 0.3 0.2
Iowa City 0.9 0.8 0.5 0.2 0.2 0.2 0.2
Lone Tree 1.1 1.1 0.9 0.6 0.4 0.3 0.2
Columbus Jct 3.7 3.7 3.2 2.5 2.0 1.5 1.1
Wapello 4.1 4.0 3.4 2.6 2.1 1.5 1.1
Oakville 4.3 4.2 3.5 2.7 2.1 1.6 1.1
:English River
Kalona 0.2 0.2 0.1 0.1 0.1 0.0 0.0
:Des Moines River
Keosauqua 2.5 2.3 2.0 1.4 0.7 0.4 0.4
St Francisville 2.7 2.5 2.0 1.5 0.7 0.5 0.4
:Fox River
Wayland 0.0 0.0 0.0 0.0 0.0 0.0 0.0
:Pecatonica River
Freeport 1.0 1.0 0.9 0.8 0.7 0.6 0.6
:Rock River
Como 4.1 4.1 4.0 3.6 3.0 2.5 2.2
Joslin 4.5 4.5 4.3 3.9 3.2 2.7 2.3
Moline 4.9 4.9 4.8 4.2 3.4 3.0 2.4
:Green River
Geneseo 0.2 0.2 0.2 0.2 0.1 0.1 0.0
:La Moine River
Colmar 0.0 0.0 0.0 0.0 0.0 0.0 0.0
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 at http://www.weather.gov/dvn for more weather and
water information.
The next outlook will be issued near the end of next month.
$$
Gunkel