Flood Potential Outlook Issued by NWS Des Moines, IA
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FGUS73 KDMX 251713 CCA
ESFDMX
IAC001-003-007-009-013-015-017-023-025-027-029-033-039-047-049-051-
053-063-069-073-075-077-079-081-083-091-099-109-117-121-123-125-127-
135-147-151-153-157-159-161-169-171-173-175-179-181-185-187-189-195-
197-132300-
Probabilistic Hydrologic Outlook
National Weather Service Des Moines IA
1112 AM CST Thu Feb 25 2021
...Spring Flood and Water Resources Outlook...
This flood outlook is for the NWS Des Moines service area. It covers
the time period for early March through late May 2001. It includes
the following rivers and their tributaries in north central, central
and south central Iowa...
Iowa, Cedar, Skunk, Des Moines, Raccoon, Nishnabotna, 102, Thompson
and Chariton Rivers
This outlook is the second in a series of three outlooks for the
spring flood season. The next outlook will be issued on March 11th.
Regular monthly long-range Probabilistic Hydrologic Outlooks will
resume on April 1st. You may also refer to the NWS Des Moines Website
for more information at... http://www.weather.gov/desmoines .
...Flood Outlook Highlights...
* The risk of minor flooding is near normal at all locations. The
risk of moderate flooding is near normal at all locations. The risk
of major flooding is near normal at all locations.
* It is important to continue monitoring weather and river
conditions--as well as future outlooks--for any changes to the
flood threat. Any future precipitation--as well as changes to
river or other weather conditions--may increase or decrease the
risk of flooding.
* Maps and graphics concerning the risk of flooding are available on
the NWS Des Moines Advanced Hydrologic Prediction Service Web page
at http://water.weather.gov/ahps2/index.php?wfo=dmx . On that page
click on the tab above the map labeled Experimental Long-Range
Flood Risk.
* You may also refer to our web site for more information at
http://www.weather.gov/desmoines .
This outlook provides long-range probabilistic river outlooks for
river basins in the NWS Des Moines 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 more 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: 03/01/2021 - 05/30/2021
: 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
-------- ----- ----- ----- : --- --- --- --- --- ---
:Cedar River
Janesville 13.0 15.0 18.0 : <5 9 <5 <5 <5 <5
:West Fork Cedar River
Finchford 17.0 18.0 20.0 : <5 <5 <5 <5 <5 <5
:Winnebago River
Mason City 10.0 14.5 15.5 : <5 <5 <5 <5 <5 <5
:Shell Rock River
Shell Rock 13.5 18.0 20.0 : 9 12 <5 <5 <5 <5
:Beaver Creek
New Hartford 12.5 14.0 15.0 : 7 9 <5 <5 <5 <5
:Cedar River
Cedar Falls 89.0 92.0 94.0 : 31 48 13 20 <5 10
:Black Hawk Creek
Hudson 14.0 15.0 19.0 : 41 39 26 24 <5 <5
:Cedar River
Waterloo 13.0 19.0 21.0 : 18 32 <5 5 <5 <5
:Iowa River
Rowan 12.5 15.0 17.0 : 9 16 <5 <5 <5 <5
Marshalltown 19.0 23.0 26.0 : <5 9 <5 <5 <5 <5
Tama Hwy E49 12.5 13.0 14.0 : 18 21 8 17 <5 <5
:South Skunk River
Ames W Riverside 12.5 16.0 16.5 : <5 <5 <5 <5 <5 <5
:Squaw Creek
Ames Lincoln Way 10.0 14.0 15.5 : <5 <5 <5 <5 <5 <5
:South Skunk River
Ames US 30 21.5 23.5 24.5 : 6 9 <5 <5 <5 <5
Colfax 18.0 19.0 21.0 : 8 7 <5 <5 <5 <5
Oskaloosa 24.5 28.5 30.0 : <5 <5 <5 <5 <5 <5
:East Fork Des Moines River
Algona 17.0 18.0 22.0 : <5 16 <5 12 <5 <5
Dakota City 20.0 24.0 28.0 : <5 6 <5 <5 <5 <5
:Boone River
Webster City 14.0 17.0 19.0 : <5 <5 <5 <5 <5 <5
:Beaver Creek
Grimes 14.0 16.0 17.0 : <5 <5 <5 <5 <5 <5
:North Raccoon River
Jefferson 19.0 21.0 23.0 : <5 7 <5 <5 <5 <5
Perry 15.0 18.0 20.0 : 28 50 11 30 5 18
:South Raccoon River
Redfield 20.0 24.0 27.0 : <5 <5 <5 <5 <5 <5
:Raccoon River
Van Meter 17.0 22.0 23.0 : 9 20 <5 <5 <5 <5
Des Moines IA 28 36.0 38.0 40.0 : 6 10 <5 <5 <5 <5
Des Moines Fleur 12.0 16.0 25.0 : 59 66 9 21 <5 <5
:North River
Norwalk 22.0 25.0 26.0 : 12 19 <5 <5 <5 <5
:Middle River
Indianola 23.0 26.0 28.0 : 9 16 <5 <5 <5 <5
:South River
Ackworth 29.0 30.0 32.0 : 6 5 <5 <5 <5 <5
:Cedar Creek
Bussey 25.0 30.0 32.0 : <5 <5 <5 <5 <5 <5
:West Fork Des Moines River
Estherville 10.0 13.0 14.5 : <5 21 <5 8 <5 <5
Emmetsburg 11.0 13.0 15.0 : <5 18 <5 <5 <5 <5
Humboldt 10.0 13.0 14.0 : 10 30 <5 <5 <5 <5
:Des Moines River
Fort Dodge 10.5 16.0 17.0 : 9 25 <5 <5 <5 <5
Stratford 19.0 25.0 27.0 : 6 18 <5 <5 <5 <5
Des Moines 2nd Av 23.0 26.0 30.0 : <5 <5 <5 <5 <5 <5
Des Moines SE 6th 24.0 26.0 30.0 : 24 46 6 15 <5 <5
Eddyville 63.0 68.0 70.0 : 6 10 <5 <5 <5 <5
Ottumwa 11.5 15.0 19.0 : 25 28 <5 <5 <5 <5
:Thompson River
Davis City 12.0 20.0 24.0 : 11 21 <5 <5 <5 <5
:South Fork Chariton River
Promise City 25.0 28.0 31.0 : <5 <5 <5 <5 <5 <5
:Chariton River
Chariton 19.5 26.0 29.0 : <5 <5 <5 <5 <5 <5
Moulton 36.0 37.0 38.0 : <5 <5 <5 <5 <5 <5
:East Nishnabotna River
Atlantic 19.0 23.0 24.0 : 12 16 <5 <5 <5 <5
:East Fork 102 River
Bedford 24.0 25.0 26.0 : <5 <5 <5 <5 <5 <5
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: 03/01/2021 - 05/30/2021
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Cedar River
Janesville 3.5 3.8 4.8 6.1 7.5 11.1 12.1
:West Fork Cedar River
Finchford 8.9 9.1 10.0 11.3 12.5 15.0 15.4
:Winnebago River
Mason City 4.5 4.6 5.2 6.2 7.3 7.9 9.0
:Shell Rock River
Shell Rock 9.2 9.3 10.0 10.7 11.7 13.3 13.8
:Beaver Creek
New Hartford 4.3 4.8 5.6 7.4 10.3 11.9 13.3
:Cedar River
Cedar Falls 82.2 82.8 84.9 87.4 89.3 92.9 93.9
:Black Hawk Creek
Hudson 9.9 10.3 12.1 13.7 15.1 15.7 16.3
:Cedar River
Waterloo 7.4 7.7 8.7 10.0 11.5 15.2 17.5
:Iowa River
Rowan 5.5 5.7 6.5 8.9 10.7 12.2 13.5
Marshalltown 11.3 11.5 12.5 14.4 16.0 17.7 18.8
Tama Hwy E49 4.9 5.3 7.1 9.9 11.3 12.9 13.3
:South Skunk River
Ames W Riverside 4.5 5.3 6.8 7.5 9.3 10.5 11.1
:Squaw Creek
Ames Lincoln Way 2.9 3.4 4.2 5.0 6.1 7.2 9.3
:South Skunk River
Ames US 30 12.6 13.5 15.5 16.9 18.6 20.5 21.6
Colfax 9.0 9.5 12.0 14.0 16.6 17.7 18.4
Oskaloosa 10.7 11.2 14.5 17.0 19.9 22.4 23.5
:East Fork Des Moines River
Algona 8.4 8.6 9.9 12.5 14.3 16.2 16.9
Dakota City 9.2 9.4 10.2 12.2 13.4 15.5 17.0
:Boone River
Webster City 4.5 4.6 5.8 7.2 9.1 10.1 11.4
:Beaver Creek
Grimes 4.5 5.1 7.2 8.6 11.0 12.2 12.9
:North Raccoon River
Jefferson 6.6 7.2 8.6 11.5 13.3 15.6 17.1
Perry 6.5 7.3 10.3 13.9 15.4 18.2 20.3
:South Raccoon River
Redfield 3.8 4.0 6.5 7.6 9.4 13.6 17.8
:Raccoon River
Van Meter 4.9 5.5 9.3 11.7 13.1 16.5 20.3
Des Moines IA 28 22.7 23.4 28.0 30.4 31.7 34.5 36.7
Des Moines Fleur 5.6 6.4 10.6 12.3 13.2 15.7 18.1
:North River
Norwalk 8.0 9.6 13.6 17.1 20.3 22.1 22.3
:Middle River
Indianola 10.4 11.3 14.6 15.7 17.8 22.7 24.1
:South River
Ackworth 8.5 9.3 11.5 13.1 19.4 24.8 29.4
:Cedar Creek
Bussey 8.0 9.4 10.9 13.7 15.8 19.1 20.7
:West Fork Des Moines River
Estherville 3.5 3.6 3.8 4.8 7.5 9.3 9.9
Emmetsburg 2.8 2.9 3.4 4.7 7.4 8.9 9.9
Humboldt 5.3 5.5 6.0 7.2 8.7 10.0 10.3
:Des Moines River
Fort Dodge 5.1 5.4 5.9 7.6 9.1 10.2 10.9
Stratford 7.9 8.4 10.3 13.4 15.4 17.7 19.5
Des Moines 2nd Av 16.7 16.9 18.2 20.6 21.1 22.0 22.2
Des Moines SE 6th 13.3 13.8 18.9 22.1 23.8 25.2 26.3
Eddyville 53.3 53.9 58.8 60.8 61.5 62.2 63.3
Ottumwa 4.4 4.7 8.3 9.9 11.6 12.6 13.8
:Thompson River
Davis City 1.7 1.9 5.5 7.3 9.7 12.2 14.5
:South Fork Chariton River
Promise City 6.4 6.7 13.8 18.7 21.2 22.0 22.5
:Chariton River
Chariton 9.0 11.8 14.7 16.3 17.0 17.6 18.7
Moulton 25.8 25.8 27.4 30.0 33.1 33.9 34.3
:East Nishnabotna River
Atlantic 5.4 6.0 7.4 12.0 15.8 19.5 20.1
:East Fork 102 River
Bedford 12.0 13.0 15.3 16.4 18.1 19.3 20.6
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--Non-Exceedance Probabilities...
Chance of Falling Below Stages
at Specific Locations
Valid Period: 03/01/2021 - 05/30/2021
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Cedar River
Janesville 1.1 1.1 1.1 1.1 1.1 1.1 1.1
:West Fork Cedar River
Finchford 5.7 5.7 5.6 5.6 5.6 5.6 5.6
:Winnebago River
Mason City 3.1 3.1 3.1 3.1 3.1 3.1 3.0
:Shell Rock River
Shell Rock 7.5 7.5 7.5 7.5 7.5 7.5 7.5
:Beaver Creek
New Hartford 1.7 1.7 1.7 1.7 1.7 1.7 1.7
:Cedar River
Cedar Falls 78.4 78.4 78.4 78.4 78.4 78.4 78.4
:Black Hawk Creek
Hudson 5.1 5.1 5.0 5.0 5.0 5.0 5.0
:Cedar River
Waterloo 5.3 5.3 5.3 5.3 5.3 5.3 5.3
:Iowa River
Rowan 3.3 3.2 3.2 3.1 3.1 3.1 3.1
Marshalltown 9.1 9.0 9.0 9.0 8.9 8.9 8.9
Tama Hwy E49 1.3 1.3 1.3 1.2 1.2 1.2 1.2
:South Skunk River
Ames W Riverside 2.8 2.8 2.8 2.8 2.8 2.8 2.4
:Squaw Creek
Ames Lincoln Way 0.8 0.8 0.8 0.8 0.8 0.8 0.7
:South Skunk River
Ames US 30 9.6 9.6 9.6 9.6 9.6 9.5 9.2
Colfax 6.7 6.7 6.7 6.7 6.7 6.7 6.5
Oskaloosa 8.4 8.3 8.2 8.2 8.0 7.8 7.7
:East Fork Des Moines River
Algona 6.8 6.7 6.7 6.7 6.5 5.9 5.7
Dakota City 7.4 7.3 7.3 7.3 7.2 7.2 7.2
:Boone River
Webster City 2.0 2.0 1.9 1.9 1.8 1.8 1.7
:Beaver Creek
Grimes 3.5 3.5 3.2 3.0 2.7 2.2 2.2
:North Raccoon River
Jefferson 5.4 5.3 5.3 5.2 5.0 4.9 4.8
Perry 4.3 4.3 4.2 4.1 3.8 3.5 3.4
:South Raccoon River
Redfield 2.7 2.7 2.6 2.4 2.3 2.1 2.0
:Raccoon River
Van Meter 3.3 3.2 3.1 2.8 2.6 2.3 2.1
Des Moines IA 28 21.0 20.9 20.8 20.5 20.2 20.0 19.8
Des Moines Fleur 3.9 3.9 3.7 3.4 3.2 2.9 2.8
:North River
Norwalk 5.8 5.8 5.7 5.5 5.1 4.9 4.8
:Middle River
Indianola 7.8 7.7 7.5 7.2 7.0 7.0 6.9
:South River
Ackworth 5.9 5.9 5.9 5.8 5.8 5.7 5.7
:Cedar Creek
Bussey 5.8 5.7 5.4 5.3 5.1 4.9 4.9
:West Fork Des Moines River
Estherville 2.2 2.2 2.2 2.2 2.2 2.0 2.0
Emmetsburg 0.4 0.4 0.4 0.3 0.3 0.3 0.3
Humboldt 3.4 3.4 3.3 3.3 3.2 3.1 2.9
:Des Moines River
Fort Dodge 3.7 3.7 3.7 3.6 3.5 3.4 3.3
Stratford 5.6 5.6 5.5 5.4 5.3 5.1 4.9
Des Moines 2nd Av 15.5 15.5 15.4 15.3 15.2 15.0 14.9
Des Moines SE 6th 10.8 10.6 10.5 10.3 9.8 9.5 9.3
Eddyville 50.8 50.6 50.1 49.7 48.8 48.3 48.1
Ottumwa 3.0 2.8 2.5 2.2 1.8 1.4 1.3
:Thompson River
Davis City 0.6 0.6 0.6 0.6 0.6 0.6 0.6
:South Fork Chariton River
Promise City 3.5 3.4 3.4 3.3 3.1 3.0 3.0
:Chariton River
Chariton 4.7 4.5 4.1 3.8 3.4 2.0 1.8
Moulton 19.1 19.0 18.7 18.6 18.5 18.5 18.4
:East Nishnabotna River
Atlantic 2.9 2.9 2.9 2.6 2.4 2.2 2.2
:East Fork 102 River
Bedford 10.7 10.7 10.7 10.7 10.7 9.7 9.2
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.
...Current Conditions as of February 25th 2021...
* Snow Pack...the snow pack is above normal across the NWS Des Moines
service area. Water equivalent of the snow pack is generally around
1 to 2 inches, however it is 2 or more inches some areas especially
eastern parts of the service area.
* Soil Moisture...soil moisture is generally below normal across the
western service area, near normal across the central service area
and below normal across the far eastern service area.
* Frost Depth...ground frost ranges from around 10 inches across the
southern service area to 10 to 15 inches across the central and
northern service area.
* Streamflows...streamflows are generally near normal across the
service area, with some places reporting slightly above normal and
some places reporting slightly below normal streamflows.
* Drought Conditions...drought conditions exist across the western
service area. They are as extreme as D2 drought across the
northwestern service area.
$$
Zogg