Flood Potential Outlook
Issued by NWS Quad Cities, IA IL
Issued by NWS Quad Cities, IA IL
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IAC011-019-031-045-055-057-061-087-095-097-101-103-105-107-111-113-
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Probabilistic Hydrologic Outlook
National Weather Service Quad Cities IA IL
1201 PM CST Thu Feb 13 2025
...2025 Spring Flood and Water Resources Outlook 1...
.Introduction:
... Below Normal Flood Risk This Spring...
This is the first of the three planned Spring Flood and Water
Resource Outlooks for 2025 for the Quad Cities Hydrologic Service
Area (HSA), which covers portions of eastern Iowa, 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, and Green Rivers in Illinois, as well as the La
Moine River in Illinois. This outlook is for thetime period from
mid February through April.
.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. While a recent system brought a widespread snowpack to the
region, low snow water equivalent and below normal precipitation
throughout the local area and the headwater areas in Minnesota and
Wisconsin will result in a lower-end flood risk at this time.
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.
3. Currently, deep frozen soils locally and near the headwaters of
the mainstem will result in less capacity for infiltration of spring
rains/snow until melting begins.
4. Local streams are currently flowing at or below the normal levels.
Through the spring, impacts from these factors are expected to
change. One of the biggest factors that will drive the flood threat
this spring will be the spring precipitation that we receive,
whether it be from rain or snow. This, combined with frozen grounds
can lead to issues down the road, but current conditions do not
favor such. Best to 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.
* While much of the HSA recently received widespread snowfall,
roughly 6-10 inches through our northern HSA and 1-4 inches in our
southern HSA, there remains some uncertainty on the impacts of the
new snowpack. Given the frozen ground, any melt from this snow
will largely become runoff. This snowpack, along with future snow
and rain from the ongoing active pattern, may lead to increases in
flood potential locally. Although, given the ongoing drought and
near 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 (10-15%
chance), but is subject to change.
* Widespread below normal soil moisture levels in the local area
increases the capacity of the soils to soak in spring precipitation
and will mitigate the near term flood risk, as well as decrease the
risk for prolonged flooding. 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 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 largely below normal so far this winter. Recent
snow received throughout the area will alleviate some of this, but
some are likely to remain below normal. With that, much of the HSA,
especially eastern Iowa and northwest Illinois, remains Abnormally
Dry or in a Moderate Drought due to well below normal precipitation
observed since the fall months in 2024. This is also reflected well
in soil moisture levels, which remain near to below normal. North of
the area, precipitation in the upper Mississippi River Basin so far
this winter has averaged below normal, aside from parts of far
northern Minnesota, which were slightly above normal.
Latest outlooks from the Climate Prediction Center (CPC) favor below
normal precipitation through the second half of February for all of
the Upper Mississippi River Basin. With dry soils and ongoing
drought, any further precipitation should be allowed to infiltrate
into the ground once we start to lose some of the frost depth. Until
then, 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
favorable for continued widespread precipitation will increase the
flood risk, especially with frozen grounds.
.Snow Cover and Liquid Water Content:
Local Rivers - Neutral to Decreased Threat
Mississippi River - Neutral to Decreased Threat
Recent snowfall has resulted in a widespread snowpack between 4-8
inches through parts of the Upper Mississippi River Valley, with a
swath of upwards to 10-12 inches in our northern HSA, per the latest
observations and analysis from the National Operational Hydrologic
Remote Sensing Center (NOHRSC). While this seems like a lot of snow,
this generally equates to 0.25-0.50" of Snow Water Equivalent (SWE),
resulting from higher snow to liquid ratios. Thus, this current snow
pack isn`t expected to have much of an impact on the flood threat
throughout the area. Although, an active pattern is expected to
continue, with more snow possible over the next one to two weeks.
Thus, the combination of increasing precipitation and frozen grounds
may lead to flood concerns in the future due to much of this going
to direct runoff, but at this time confidence remains low.
.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. 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, we
have seen a reduction in frost depth over the last week, which may
start to alleviate some future flood concerns. Any frost depth can
become problematic with further precipitation this spring, prior to
thaw, as much of the precipitation will fall as runoff, rather than
infiltrate easily into the soil. This will be dependent on
precipitation though, yielding a Neutral Threat to the overall flood
threat.
.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 near to below normal. 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 Threatfor 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 well above normal temperatures that have allowed for some
of this ice to melt and/or breakup. Bouts of very cold air are
expected through the next week or two, which may allow for some ice
development, but without a prolonged period of extreme cold, the
development of widespread river ice and ice jam flooding seems low
at the moment. 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 climate outlooks from the Climate Prediction
Center, probabilities are leaning toward below normal temperatures
for much of the region for the remainder of February and into the
first week of March, with a signal for near normal precipitation
during the same timeframe.
The outlook for mid March through April is leaning towards near
normal temperatures for much of the region, with somewhat 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 also been well below normal for much of
the winter, with an uptick seen in mid February, as well as more
chances in the next two weeks. The threat for ice jam flooding seems
to be neutral at this point, but will be dependent on an extended
period of extreme cold to develop more ice. Current conditions are
unfavorable for snowmelt or ice jam flooding on local tributaries.
Some factors contributing to the current risk levels include: 1) The
general lack of precipitation this winter, keeping us below normal.
A recent system brought a widespread area of 6-10 inches of snowpack
throughout the region, with more chances for precipitation in the
next two weeks. 2) Deep, frozen grounds across the upper Mississippi
River Basin will prevent much infiltration until thawed. 3) Near to
below normal stream flows and 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: 02/17/2025 - 05/18/2025
: 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 : 27 48 19 39 9 12
Dubuque 17.0 18.0 21.5 : 30 53 23 47 10 16
Bellevue LD12 17.0 18.0 20.0 : 19 37 13 32 9 12
Fulton LD13 16.0 18.0 20.0 : 28 51 17 35 10 15
Camanche 17.0 18.5 20.5 : 23 46 17 35 11 15
Le Claire LD14 11.0 12.0 13.5 : 28 51 19 37 12 22
Rock Island LD15 15.0 16.0 18.0 : 36 56 28 50 14 27
Ill. City LD16 15.0 16.0 18.0 : 34 56 26 46 13 27
Muscatine 16.0 18.0 20.0 : 38 57 26 46 13 27
New Boston LD17 15.0 16.5 18.5 : 38 60 30 51 18 32
Keithsburg 14.0 15.5 17.0 : 38 60 31 49 16 27
Gladstone LD18 10.0 12.0 14.0 : 39 61 28 47 13 24
Burlington 15.0 16.5 18.0 : 37 59 28 47 15 28
Keokuk LD19 16.0 17.5 19.0 : 20 32 13 21 9 12
Gregory Landing 15.0 18.0 25.0 : 46 62 22 42 <5 <5
:Maquoketa River
Manchester Hwy 20 14.0 17.0 20.0 : 16 20 10 15 <5 6
Maquoketa 24.0 26.0 28.5 : 23 19 16 16 5 6
:Wapsipinicon River
Independence 12.0 13.0 15.0 : 5 7 <5 6 <5 <5
Anamosa Shaw Rd 14.5 18.0 21.5 : 15 23 7 11 <5 <5
De Witt 4S 11.0 11.5 12.5 : 73 72 65 65 26 43
:North Skunk River
Sigourney 16.0 18.0 21.0 : 59 56 31 41 7 12
:Skunk River
Augusta 15.0 17.0 20.0 : 42 41 21 28 10 13
:Cedar River
Vinton 15.0 18.0 19.0 : 5 15 <5 5 <5 <5
Palo Blairs Ferry 12.5 15.5 17.0 : 8 23 <5 5 <5 <5
Cedar Rapids 12.0 14.0 16.0 : 13 32 5 14 <5 8
Cedar Bluff 16.0 20.0 26.0 : 10 30 <5 8 <5 <5
Conesville 13.0 15.0 16.5 : 28 52 5 13 <5 6
:Iowa River
Marengo 15.0 17.0 19.0 : 53 71 28 42 <5 6
Iowa City 23.5 24.5 26.0 : <5 <5 <5 <5 <5 <5
Lone Tree 16.0 18.5 22.0 : 30 32 5 7 <5 <5
Columbus Jct 23.0 25.0 26.5 : 7 18 <5 6 <5 <5
Wapello 21.0 25.0 27.5 : 28 53 <5 7 <5 <5
Oakville 11.0 15.0 20.0 : 22 40 <5 6 <5 <5
:English River
Kalona 14.0 16.0 18.0 : 53 55 24 33 11 15
:Des Moines River
Keosauqua 22.0 25.0 27.0 : 8 10 <5 <5 <5 <5
St Francisville 18.0 22.0 25.0 : 33 37 6 7 <5 <5
:Fox River
Wayland 15.0 18.0 20.0 : 28 22 8 9 <5 <5
:Pecatonica River
Freeport 13.0 14.0 16.0 : 38 38 25 23 <5 <5
:Rock River
Como 12.5 15.5 18.0 : 11 24 <5 11 <5 <5
Joslin 12.0 14.0 16.5 : 51 56 25 33 8 19
Moline 12.0 13.0 14.0 : 48 53 23 32 9 26
:Green River
Geneseo 15.0 16.5 18.0 : 16 27 9 13 <5 <5
:La Moine River
Colmar 20.0 22.0 24.0 : 55 61 45 43 21 18
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: 02/17/2025 - 05/18/2025
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Mississippi River
Dubuque LD11 8.1 9.6 10.8 12.7 16.1 20.1 21.3
Dubuque 10.3 11.5 12.6 14.6 17.9 21.8 23.1
Bellevue LD12 8.9 10.3 11.4 13.2 16.1 19.5 20.7
Fulton LD13 8.6 10.0 11.7 13.2 16.4 20.4 21.4
Camanche 11.0 11.9 13.0 14.0 16.9 21.0 22.1
Le Claire LD14 6.7 7.5 8.6 9.3 11.2 14.4 15.4
Rock Island LD15 9.5 10.3 11.6 13.0 16.3 19.2 20.4
Ill. City LD16 8.1 8.9 11.3 12.4 16.1 19.2 20.8
Muscatine 9.9 10.7 12.7 14.0 18.1 21.0 22.5
New Boston LD17 9.7 10.6 12.7 13.8 17.2 20.3 21.5
Keithsburg 10.0 10.7 12.2 13.1 15.9 18.3 19.6
Gladstone LD18 5.4 6.3 8.2 9.2 12.2 14.9 16.6
Burlington 11.1 11.7 13.3 14.2 16.8 19.4 20.7
Keokuk LD19 7.3 7.9 10.1 11.5 15.1 18.7 20.3
Gregory Landing 9.1 10.2 12.9 14.4 17.8 20.9 22.9
:Maquoketa River
Manchester Hwy 20 6.0 6.5 7.7 8.7 11.2 17.0 19.6
Maquoketa 12.5 13.0 15.4 18.3 23.9 27.6 28.5
:Wapsipinicon River
Independence 5.6 5.8 6.7 7.5 8.5 11.2 12.8
Anamosa Shaw Rd 6.8 8.0 9.1 10.9 12.9 16.4 19.5
De Witt 4S 8.8 9.7 10.8 12.0 12.7 13.4 13.7
:North Skunk River
Sigourney 10.0 11.5 14.3 16.6 19.0 20.3 22.4
:Skunk River
Augusta 5.9 7.2 11.3 13.6 16.5 20.1 23.5
:Cedar River
Vinton 4.8 5.2 7.1 9.9 12.2 14.2 15.6
Palo Blairs Ferry 4.7 5.0 7.0 8.6 10.8 12.2 13.5
Cedar Rapids 4.8 5.0 6.2 7.7 10.2 12.4 14.7
Cedar Bluff 7.2 7.8 9.4 11.1 13.9 16.0 18.6
Conesville 8.3 8.9 10.2 11.4 13.5 14.5 15.2
:Iowa River
Marengo 9.3 10.3 12.4 15.1 17.3 18.2 18.6
Iowa City 12.2 12.9 14.9 16.6 19.0 19.6 20.9
Lone Tree 9.3 10.6 11.6 14.1 16.4 17.9 18.7
Columbus Jct 13.3 14.1 16.1 17.8 19.6 22.6 23.6
Wapello 16.2 16.9 18.4 19.7 21.4 23.4 24.2
Oakville 5.1 5.8 7.3 8.8 10.5 12.6 13.5
:English River
Kalona 9.5 10.6 12.8 14.2 15.9 18.1 19.5
:Des Moines River
Keosauqua 13.3 15.7 17.2 18.5 20.2 21.5 23.1
St Francisville 10.7 13.1 15.4 16.8 18.9 20.4 23.7
:Fox River
Wayland 5.9 6.3 9.4 12.5 15.3 17.8 19.0
:Pecatonica River
Freeport 7.1 7.9 9.3 11.8 14.0 14.8 15.5
:Rock River
Como 5.7 6.1 6.9 9.1 10.8 13.0 15.2
Joslin 8.8 9.4 10.0 12.1 14.0 15.9 18.4
Moline 9.5 9.9 10.6 11.9 12.9 13.9 16.6
:Green River
Geneseo 6.2 7.0 9.9 11.2 13.7 16.3 17.5
:La Moine River
Colmar 9.5 12.1 16.9 21.2 23.6 24.8 26.3
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: 02/17/2025 - 05/18/2025
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Mississippi River
Dubuque LD11 23.1 23.1 23.0 22.9 22.3 21.9 21.3
Dubuque 23.1 23.1 23.0 22.9 22.3 21.9 21.3
Bellevue LD12 23.0 23.0 22.9 22.8 22.6 22.2 21.8
Fulton LD13 23.8 23.8 23.7 23.6 23.6 23.4 23.1
Camanche 23.8 23.8 23.7 23.6 23.6 23.4 23.1
Le Claire LD14 24.5 24.5 24.5 24.4 24.3 24.3 24.1
Rock Island LD15 27.3 27.3 27.2 27.1 27.0 26.9 26.7
Ill. City LD16 28.2 28.2 28.2 28.0 28.0 27.9 27.7
Muscatine 28.2 28.2 28.2 28.0 28.0 27.9 27.7
New Boston LD17 28.3 28.3 28.2 28.1 28.1 28.0 27.8
Keithsburg 30.7 30.7 30.6 30.5 30.5 30.1 29.6
Gladstone LD18 30.7 30.7 30.6 30.5 30.5 30.1 29.6
Burlington 30.8 30.8 30.7 30.6 30.6 30.3 29.8
Keokuk LD19 31.7 31.7 31.6 31.5 31.5 31.5 30.8
Gregory Landing 32.5 32.5 32.5 32.4 32.3 32.3 32.2
:Maquoketa River
Manchester Hwy 20 0.1 0.1 0.1 0.1 0.1 0.1 0.1
Maquoketa 0.5 0.5 0.5 0.5 0.5 0.5 0.4
:Wapsipinicon River
Independence 0.2 0.2 0.2 0.2 0.2 0.2 0.2
Anamosa Shaw Rd 0.4 0.4 0.4 0.4 0.4 0.4 0.4
De Witt 4S 0.7 0.7 0.7 0.7 0.6 0.6 0.6
:North Skunk River
Sigourney 0.1 0.1 0.1 0.1 0.1 0.1 0.0
:Skunk River
Augusta 0.7 0.7 0.7 0.6 0.6 0.6 0.5
:Cedar River
Vinton 0.9 0.9 0.8 0.8 0.8 0.8 0.8
Palo Blairs Ferry 0.9 0.9 0.9 0.9 0.9 0.9 0.9
Cedar Rapids 1.0 1.0 1.0 1.0 1.0 0.9 0.9
Cedar Bluff 1.1 1.1 1.1 1.1 1.1 1.0 1.0
Conesville 1.4 1.4 1.4 1.4 1.3 1.3 1.2
:Iowa River
Marengo 0.4 0.4 0.3 0.3 0.3 0.3 0.3
Iowa City 0.4 0.4 0.4 0.3 0.2 0.2 0.2
Lone Tree 0.5 0.5 0.4 0.4 0.4 0.3 0.3
Columbus Jct 2.0 1.9 1.9 1.9 1.8 1.7 1.7
Wapello 2.1 2.1 2.0 1.9 1.9 1.8 1.7
Oakville 2.2 2.2 2.1 2.0 1.9 1.8 1.7
:English River
Kalona 0.0 0.0 0.0 0.0 0.0 0.0 0.0
:Des Moines River
Keosauqua 0.6 0.6 0.5 0.5 0.5 0.5 0.5
St Francisville 0.7 0.6 0.6 0.6 0.6 0.6 0.6
:Fox River
Wayland 0.0 0.0 0.0 0.0 0.0 0.0 0.0
:Pecatonica River
Freeport 0.7 0.7 0.7 0.7 0.7 0.6 0.6
:Rock River
Como 2.8 2.8 2.8 2.7 2.7 2.6 2.5
Joslin 3.0 3.0 3.0 2.9 2.9 2.8 2.7
Moline 3.4 3.4 3.3 3.3 3.3 3.1 3.0
:Green River
Geneseo 0.2 0.2 0.2 0.2 0.2 0.1 0.1
: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