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Every spring the National Weather Service (NWS) prepares a series of flood outlooks for the potential of river flooding as a result of snow pack melt.
Each outlook takes into account anticedent conditions and current snowpack levels to anticipate the overall flood risk. The rate and timing of melt, in addition to future precipitation, can alter conditions as well.
These outlooks contain information about the potential for flooding throughout the spring months. The information can help decision makers and those with river interests prepare, in order to protect life and property.
Spring Snowmelt Flood Outlook Release Dates:
...NEAR TO BELOW AVERAGE RISK OF FLOODING THIS SPRING...
This outlook references information from the following partners
including: the United States Geological Survey (USGS), the U.S.
Army Corps of Engineers, Regional Climate Centers, U.S. Drought
Monitor, the Climate Prediction Center and NOAA Office of Water
Prediction.
This is the first in a series of three spring flood outlooks. The
next outlook will be provided on February 29, 2024.
Flood outlook factors...
Soil moisture values across most of northeast Wisconsin is now
considered normal to below normal. Northern Wisconsin was considered
below normal mainly due to the dry conditions that carried over from
2023. Once the ground thaws, this would allow more moisture to be
absorbed into the soils and result in a normal runoff.
Streamflows range from below normal over north-central Wisconsin, to
above normal over parts of east-central Wisconsin. This scenario
would likely lead to normal river levels and an average risk of
flooding across northern and central Wisconsin. However, the high
streamflows over east-central Wisconsin may lead to above normal
river levels and an average to above average risk of flooding across
east-central Wisconsin.
Snow water equivalent indicated that much of northeast Wisconsin was
well-below normal, primarily due to warmer than normal temperatures
and below normal snowfall. The exception was east-central Wisconsin
where snowfall was considered slightly below normal due to the major
snowstorm in January.
Frost depth this season is considered shallow, even more shallow
than last year. This was due again to the above normal temperatures
seen so far this winter. Frost depths ranged from zero to around 20
inches, which is similar to the same time in 2023. The more shallow
frost depth may lead to decreased runoff as the less frozen ground
will allow water to readily pass through the surface.
Lake Michigan water levels continue to run slightly above normal
which has been the case the past two years. This level will allow
for decreased flooding impacts this season. For a comparison of
impacts, there were very few impacts in 2022 and 2023, and Lake
Michigan levels are slightly lower this year.
The warm conditions for most of January 2024 and well-above normal
temperatures through early February has led to thinner ice on area
rivers this season. There is a low risk of break up ice jamming on
area rivers this season. The potential for ice jams generally
increases with heavy rainfall events before the ice is out of the
river system.
...Weather/climate outlook...
Temperatures are expected to trend above normal through the last
half of February. This would lend support to a quicker snowmelt and
a faster release of the water in the snowpack. Precipitation during
this same time frame has a normal to slightly better chance to trend
above normal. There is a signal for these conditions to become
normal to slightly better chance to trend below normal February
through April time frame.
...Probabilistic Forecast Information for River Forecast Points...
In Table 1 below, the current (CS) and historical (HS) or normal
probabilities of exceeding Minor...Moderate...And Major flood stage
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: 02/19/2024 - 05/19/2024
: 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
-------- ----- ----- ----- : --- --- --- --- --- ---
:WISCONSIN RIVER
MERRILL 11.0 13.5 15.0 : <5 24 <5 <5 <5 <5
ROTHSCHILD 25.0 27.0 28.0 : <5 21 <5 8 <5 6
:YELLOW RIVER
BABCOCK 12.0 15.9 16.6 : 51 78 10 18 <5 11
:WISCONSIN RIVER
WISCONSIN RAPIDS 12.0 13.5 14.5 : <5 11 <5 <5 <5 <5
:OCONTO RIVER
OCONTO 9.0 12.0 14.0 : 11 24 <5 <5 <5 <5
:UPPER WOLF RIVER
LANGLADE 11.5 12.5 14.0 : <5 <5 <5 <5 <5 <5
:WOLF RIVER
SHIOCTON 11.0 13.5 15.0 : 28 44 <5 5 <5 <5
NEW LONDON 9.0 10.5 11.1 : 33 50 <5 6 <5 <5
:LITTLE WOLF RIVER
ROYALTON 5.0 8.0 10.0 : 24 40 <5 <5 <5 <5
:WAUPACA RIVER
WAUPACA 6.0 7.5 9.0 : <5 8 <5 <5 <5 <5
:FOX RIVER
APPLETON 8.4 9.0 10.5 : <5 <5 <5 <5 <5 <5
:MENOMINEE RIVER
FLORENCE 9.0 11.0 13.0 : 6 37 <5 14 <5 <5
NIAGARA 13.0 15.0 16.0 : <5 32 <5 14 <5 <5
VULCAN 15.0 17.0 19.0 : <5 25 <5 6 <5 <5
MCALLISTER 15.0 18.0 19.0 : 12 52 <5 14 <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: 02/19/2024 - 05/19/2024
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:WISCONSIN RIVER
MERRILL 5.8 6.1 6.6 7.6 8.3 9.2 11.0
ROTHSCHILD 16.3 16.9 18.5 19.5 21.2 23.2 24.4
:YELLOW RIVER
BABCOCK 5.9 7.3 8.3 12.1 14.1 15.9 16.2
:WISCONSIN RIVER
WISCONSIN RAPIDS 4.1 4.8 5.6 6.5 8.2 9.5 10.5
:OCONTO RIVER
OCONTO 6.2 6.3 6.7 7.3 8.1 9.1 10.0
:UPPER WOLF RIVER
LANGLADE 8.2 8.4 8.6 8.8 9.1 9.3 9.6
:WOLF RIVER
SHIOCTON 7.4 8.4 9.1 10.2 11.1 11.9 12.5
NEW LONDON 6.3 7.5 7.8 8.6 9.2 9.7 9.9
:LITTLE WOLF RIVER
ROYALTON 2.9 3.1 3.6 4.2 5.0 5.9 6.1
:WAUPACA RIVER
WAUPACA 2.4 2.5 2.9 3.6 4.7 5.0 5.2
:FOX RIVER
APPLETON 6.2 6.3 6.5 7.0 7.5 7.9 7.9
:MENOMINEE RIVER
FLORENCE 4.6 4.9 5.4 6.1 7.0 8.5 9.1
NIAGARA 7.0 7.2 7.9 8.8 10.0 11.8 12.5
VULCAN 7.1 7.5 8.4 9.4 10.8 12.8 13.7
MCALLISTER 10.8 11.3 11.9 12.7 13.8 15.2 16.1
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: 02/19/2024 - 05/19/2024
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:WISCONSIN RIVER
MERRILL 4.6 4.5 4.4 4.3 4.2 4.1 4.0
ROTHSCHILD 13.2 13.1 13.1 12.9 12.6 12.5 12.3
:YELLOW RIVER
BABCOCK 2.1 2.1 2.0 2.0 1.9 1.9 1.9
:WISCONSIN RIVER
WISCONSIN RAPIDS 1.5 1.5 1.4 1.3 1.3 1.3 1.3
:OCONTO RIVER
OCONTO 4.5 4.4 4.4 4.4 4.4 4.3 4.3
:UPPER WOLF RIVER
LANGLADE 7.7 7.7 7.7 7.6 7.6 7.6 7.6
:WOLF RIVER
SHIOCTON 3.9 3.8 3.7 3.5 3.3 3.1 3.0
NEW LONDON 2.7 2.6 2.5 2.3 2.2 2.1 2.0
:LITTLE WOLF RIVER
ROYALTON 1.4 1.3 1.3 1.2 1.2 1.2 1.2
:WAUPACA RIVER
WAUPACA 1.5 1.5 1.5 1.5 1.5 1.5 1.5
:FOX RIVER
APPLETON 5.6 5.5 5.3 5.1 4.9 4.9 4.9
:MENOMINEE RIVER
FLORENCE 3.2 3.2 3.1 3.1 3.1 3.1 3.1
NIAGARA 4.9 4.9 4.9 4.9 4.8 4.8 4.8
VULCAN 5.1 5.0 5.0 5.0 5.0 5.0 4.9
MCALLISTER 8.8 8.8 8.8 8.7 8.7 8.7 8.7
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 weather.gov/grb for more weather and water
information
The next outlook will be issued February 29, 2024.
...BELOW AVERAGE RISK OF FLOODING THIS SPRING...
This outlook references information from the following partners
including: the United States Geological Survey (USGS), the U.S.
Army Corps of Engineers, Regional Climate Centers, U.S. Drought
Monitor, the Climate Prediction Center and NOAA Office of Water
Prediction.
This is the second in a series of three spring flood outlooks. The
next outlook will be provided on March 14, 2024.
Flood outlook factors...
Soil moisture values across all of northeast Wisconsin is now
considered below normal. The lack of snowfall this winter will allow
for more moisture to be absorbed into the soils and play a large
role in the decreased flood risk.
Streamflows range from below normal over north-central Wisconsin, to
normal or above normal over parts of central and eastern Wisconsin.
This scenario would likely lead to normal river levels and an
average risk of flooding.
Snow water equivalent indicated that much of northeast Wisconsin was
well-below normal, primarily due to warmer than normal temperatures
and below normal snowfall. This will also lead to a decreased flood
risk.
Frost depth this season is considered shallow, even more shallow
than last year. This was due again to the above normal temperatures
seen so far this winter. Frost depths ranged from zero to around 17
inches, which for the most part is less than the same time in 2023.
The more shallow frost depth may lead to decreased runoff as the
less frozen ground will allow water to readily pass through the
surface.
Lake Michigan water levels continue to run slightly above normal
which has been the case the past two years. This level will allow
for decreased flooding impacts this season. For a comparison of
impacts, there were very few impacts in 2022 and 2023, and Lake
Michigan levels are slightly lower this year.
The warm conditions for most of January and February 2024 has led to
thinner ice or no ice on area rivers this season. Therefore, there
is a low risk of break up ice jamming on area rivers this season.
The potential for ice jams generally increases with heavy rainfall
events before the ice is out of the river system.
...Weather/climate outlook...
Temperatures are expected to trend above normal through the second
week of March. Precipitation during this same time frame has an
enhanced odds of being above normal. There is a signal for these
conditions to remain above normal for the March-April-May time frame
and equal chances of above, near or below average precipitation.
In Table 1 below, the current (CS) and historical (HS) or normal
probabilities of exceeding Minor...Moderate...And Major flood stage
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: 03/04/2024 - 06/02/2024
: 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
-------- ----- ----- ----- : --- --- --- --- --- ---
:WISCONSIN RIVER
MERRILL 11.0 13.5 15.0 : <5 24 <5 <5 <5 <5
ROTHSCHILD 25.0 27.0 28.0 : <5 21 <5 8 <5 6
:YELLOW RIVER
BABCOCK 12.0 15.9 16.6 : 35 78 8 22 <5 7
:WISCONSIN RIVER
WISCONSIN RAPIDS 12.0 13.5 14.5 : <5 11 <5 <5 <5 <5
:OCONTO RIVER
OCONTO 9.0 12.0 14.0 : 6 24 <5 <5 <5 <5
:UPPER WOLF RIVER
LANGLADE 11.5 12.5 14.0 : <5 <5 <5 <5 <5 <5
:WOLF RIVER
SHIOCTON 11.0 13.5 15.0 : 19 44 <5 5 <5 <5
NEW LONDON 9.0 10.5 11.1 : 17 51 <5 6 <5 <5
:LITTLE WOLF RIVER
ROYALTON 5.0 8.0 10.0 : 15 41 <5 <5 <5 <5
:WAUPACA RIVER
WAUPACA 6.0 7.5 9.0 : <5 8 <5 <5 <5 <5
:FOX RIVER
APPLETON 8.4 9.0 10.5 : <5 <5 <5 <5 <5 <5
:MENOMINEE RIVER
FLORENCE 9.0 11.0 13.0 : <5 37 <5 14 <5 <5
NIAGARA 13.0 15.0 16.0 : <5 32 <5 14 <5 5
VULCAN 15.0 17.0 19.0 : <5 25 <5 6 <5 <5
MCALLISTER 15.0 18.0 19.0 : 10 53 <5 14 <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: 03/04/2024 - 06/02/2024
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:WISCONSIN RIVER
MERRILL 6.0 6.2 6.6 7.2 7.7 8.7 10.0
ROTHSCHILD 16.5 17.0 18.1 18.9 20.1 21.6 23.7
:YELLOW RIVER
BABCOCK 5.5 7.2 8.0 10.8 12.7 15.4 15.9
:WISCONSIN RIVER
WISCONSIN RAPIDS 4.3 4.6 5.3 6.1 7.1 8.5 9.4
:OCONTO RIVER
OCONTO 5.6 6.1 6.4 7.0 7.6 8.7 9.3
:UPPER WOLF RIVER
LANGLADE 8.3 8.4 8.6 8.7 9.0 9.2 9.6
:WOLF RIVER
SHIOCTON 7.0 7.7 8.9 9.7 10.6 11.4 12.1
NEW LONDON 6.4 6.8 7.5 8.3 8.9 9.3 9.6
:LITTLE WOLF RIVER
ROYALTON 2.8 3.1 3.4 3.8 4.6 5.3 5.7
:WAUPACA RIVER
WAUPACA 2.3 2.4 2.8 3.5 4.4 4.9 5.3
:FOX RIVER
APPLETON 6.1 6.2 6.4 6.8 7.2 7.5 7.8
:MENOMINEE RIVER
FLORENCE 4.4 4.6 5.2 6.0 6.9 8.3 8.9
NIAGARA 6.7 6.9 7.8 8.7 9.9 11.2 12.4
VULCAN 6.8 7.2 7.9 9.1 10.5 12.0 13.3
MCALLISTER 10.4 10.8 11.6 12.5 13.5 15.0 15.5
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: 03/04/2024 - 06/02/2024
LOCATION 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:WISCONSIN RIVER
MERRILL 4.7 4.6 4.5 4.2 4.2 4.0 3.9
ROTHSCHILD 13.5 13.4 13.1 12.8 12.6 12.5 12.3
:YELLOW RIVER
BABCOCK 2.2 2.1 2.0 2.0 2.0 1.9 1.9
:WISCONSIN RIVER
WISCONSIN RAPIDS 3.0 2.9 1.5 1.4 1.4 1.3 1.3
:OCONTO RIVERThis would lend support to a quicker snowmelt and a
faster release of the water in the snowpack.
OCONTO 5.0 4.9 4.7 4.5 4.4 4.3 4.3
:UPPER WOLF RIVER
LANGLADE 7.9 7.9 7.8 7.7 7.7 7.6 7.6
:WOLF RIVER
SHIOCTON 5.4 5.0 4.3 3.8 3.3 3.0 2.9
NEW LONDON 3.8 3.6 2.9 2.5 2.2 2.0 1.9
:LITTLE WOLF RIVER
ROYALTON 1.4 1.4 1.3 1.3 1.2 1.2 1.2
:WAUPACA RIVER
WAUPACA 1.6 1.6 1.6 1.5 1.5 1.5 1.4
:FOX RIVER
APPLETON 5.6 5.3 5.1 4.9 4.9 4.9 4.9
:MENOMINEE RIVER
FLORENCE 3.6 3.5 3.3 3.2 3.2 3.2 3.1
NIAGARA 5.6 5.5 5.2 5.1 5.0 5.0 4.9
VULCAN 5.7 5.6 5.3 5.2 5.1 5.1 5.0
MCALLISTER 9.5 9.5 9.1 9.0 8.9 8.8 8.8
Visit our web site at weather.gov/grb for more weather and water
information.
The next outlook will be issued on March 14, 2024.
COMING SOON!
References
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