Flood Potential Outlook
Issued by NWS Grand Rapids, MI
Issued by NWS Grand Rapids, MI
969
FGUS73 KGRR 271226
ESFGRR
MIC005-015-025-035-037-045-057-065-067-073-075-077-081-085-
105-107-117-121-123-127-133-139-159-141600-
PROBABILISTIC HYDROLOGIC OUTLOOK
NATIONAL WEATHER SERVICE Grand Rapids MI
725 AM EST Thu Feb 27 2025
...2025 SPRING FLOOD AND WATER RESOURCES OUTLOOK NUMBER 2...
This Spring Flood and Water Resources Outlook is for the rivers in
Southwest Lower Michigan.
...Flood Outlook Highlights...
The overall flood risk this spring is below average across the vast
majority of Southwest and West-Central Michigan (Grand, Kalamazoo,
and Muskegon River basins). This reduced risk is mainly the result of
below-average snowpack, low river levels, and drier-than-normal soil
moisture. A few rivers are still ice-covered, which does raise the
possibility of ice jams, but this ice is weakening by the day and the
risk of ice jams is slowly decreasing.
...Flood Terminology...
The term minor flooding is used to indicate minimal or no property
damage. However, some public inconvenience is possible.
The term moderate flooding is used to indicate some inundation of
structures and roads near streams. Some evacuations of people and/or
transfer of property to higher elevations may be needed.
The term major flooding is used to indicate extensive inundation of
structures and roads. Significant evacuations of people and/or
transfer of property to higher elevations will be needed.
...Probabilistic Outlook...
The flood risk this spring is below normal in all river basins in
Southwest and West-Central Lower Michigan. The chance of reaching
minor flood levels this spring currently stands at less than 40% at
all of the forecast locations on our rivers.
...Past Precipitation...
The fall and early winter period was much drier than normal.
Precipitation totals moved closer to normal for December, before
dropping well-below normal again in January and early February. In
general, it`s been a fairly cold and relatively dry winter. A recent
increase in weather systems through the Great Lakes has brought more
typical amounts of precipitation over the last few weeks, and this
trend looks to continue through spring.
...River Conditions...
Water levels throughout the Muskegon River basin are below average
for this time of year. Meanwhile, throughout the Grand and Kalamazoo
basins, the rivers are running near or slightly above average due to
the recent melting of most/all of the winter snowpack earlier this
week. No rivers reached bankfull from this snowmelt, and in general
water levels have no begun to fall. Overall, our rivers have more
room to handle runoff than normal for this stage in the spring, which
lowers the overall spring flood risks.
...Soil Moisture and Frost Depths...
Soil moisture is significantly below average (drier than normal)
across virtually all of Lower Michigan. This is primarily due to the
very dry fall and early winter period - thus the soils stand ready to
absorb a higher-than-normal amount of spring meltwater. Meanwhile,
the ground is frozen thicker/deeper than it has been for the last
several years, with frost depths likely ranging from 3 inches in the
Kalamazoo basin to 5-9 inches across the Grand and Muskegon basins.
This is several inches thicker/deeper than normal, and could play a
part in increasing runoff if we get a heavy rain event over the next
week or two.
...Snow Cover and Liquid Water Content...
The snow cover - including the amount of water being held in that
snow - is below average for nearly all areas of southwest and west-
central Michigan, including the Muskegon, Grand, and Kalamazoo River
basins. Earlier this week, much of the snow melted out from the Grand
and Kalamazoo basins, and that water is now working its way through
the rivers. In general, this was between 0.5 and 1.5 inches of snow
water equivalent that melted.
In the Muskegon River basin, estimated snow water amounts range from
0.5 to 1.5 across most of the area, with the exception of the extreme
headwaters around Cadillac and Houghton Lake where 3 to 5 inches of
snow water is likely contained in the snowpack. Overall, lower than
normal snow water amounts will lower the spring flood risks in this
area.
...River Ice Conditions...
The stable ice cover generally remains intact across most of the
Muskegon River. However, the ice is weakening/breaking up smoothly
but steadily in the Grand and Kalamazoo rivers with recent warm
temperatures. Ice jam risks are lowering rapidly across the Grand and
Kalamazoo rivers, but remain possible across the Muskegon River. As
we turn the corner into March, a slow and steady warmup will be most
helpful to weaken and melt this remaining ice without the risk of
breakup ice jams. Conversely, a sudden warmup and heavy rain event
could send significantly increased water through the rivers and force
the ice to break up. This will be an important risk to monitor as we
progress through the spring season across the Muskegon River.
...Weather Outlook.
The single biggest factor affecting flood risks are the weather
conditions during the sensitive period of melting snow. A slow snow
melt with little or no rainfall is ideal to avoid flooding. On the
other hand, a rapid warmup accompanied by heavy rain is a much worse
scenario for spring flooding - especially if the rivers are covered
with ice. At this time, the long-range weather forecasts suggest
near-normal temperatures with above-average precipitation. A possible
regional rainstorm near the middle of next week is the next weather
event to watch and evaluate for possible flood concerns.
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: 03/03/2025 - 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
-------- ----- ----- ----- : --- --- --- --- --- ---
:Grand River
Jackson 14.0 15.0 16.0 : 8 26 <5 11 <5 <5
:Buck Creek
Grandville 9.0 10.5 12.0 : 10 11 5 5 <5 <5
:Grand River
Eaton Rapids 6.0 8.0 9.0 : <5 <5 <5 <5 <5 <5
Dimondale 13.0 14.0 16.0 : <5 <5 <5 <5 <5 <5
:Red Cedar River
Williamston 9.0 10.0 10.5 : <5 <5 <5 <5 <5 <5
East Lansing 7.0 10.0 13.0 : 17 24 <5 <5 <5 <5
:Sycamore Creek
Holt 8.0 9.0 10.0 : 35 34 6 7 <5 <5
:Grand River
Lansing 11.0 13.0 15.0 : <5 13 <5 <5 <5 <5
Grand Ledge 11.0 13.0 15.0 : <5 <5 <5 <5 <5 <5
Portland 12.0 14.0 16.0 : <5 <5 <5 <5 <5 <5
:Looking Glass River
Eagle 7.0 9.0 11.0 : 31 44 5 9 <5 <5
:Maple River
Maple Rapids 9.0 11.0 13.0 : 39 71 <5 <5 <5 <5
:Grand River
Ionia 21.0 23.0 25.0 : 9 23 <5 <5 <5 <5
:Flat River
Smyrna 8.5 9.5 10.5 : <5 5 <5 <5 <5 <5
:Grand River
Lowell 15.0 18.0 20.0 : <5 20 <5 <5 <5 <5
:Thornapple River
Hastings 7.0 9.0 10.0 : 16 38 <5 <5 <5 <5
Caledonia 10.0 12.0 14.0 : <5 15 <5 <5 <5 <5
:Grand River
Ada 20.0 22.0 25.0 : <5 11 <5 <5 <5 <5
:Rogue River
Rockford 8.0 10.0 11.0 : 7 21 <5 <5 <5 <5
:Grand River
Grand Rapids 18.0 21.0 23.0 : <5 15 <5 <5 <5 <5
:Pere Marquette River
Scottville 5.5 6.5 7.0 : <5 5 <5 <5 <5 <5
:White River
Whitehall 6.0 7.0 8.0 : <5 9 <5 <5 <5 <5
:Muskegon River
Evart 12.0 13.0 14.0 : 13 25 <5 9 <5 <5
:Little Muskegon River
Morley 6.0 7.0 8.0 : <5 <5 <5 <5 <5 <5
:Muskegon River
Croton 9.0 11.0 12.0 : 15 40 <5 5 <5 <5
Newaygo 11.0 14.0 15.0 : 36 59 <5 10 <5 6
Bridgeton 13.0 16.0 17.0 : 28 54 <5 10 <5 6
:Kalamazoo River
Marshall 8.0 9.0 10.0 : <5 11 <5 8 <5 7
:Battle Creek
Battle Creek 4.0 5.0 6.0 : <5 <5 <5 <5 <5 <5
:Kalamazoo River
Battle Creek 9.0 10.0 11.0 : <5 <5 <5 <5 <5 <5
Comstock 9.0 10.0 11.0 : <5 8 <5 <5 <5 <5
New Richmond 17.0 19.0 21.0 : <5 9 <5 <5 <5 <5
:St. Joseph River
Burlington 6.5 9.0 11.0 : <5 17 <5 <5 <5 <5
:Portage River
Vicksburg 5.5 7.0 8.0 : <5 7 <5 <5 <5 <5
:Chippewa River
Mt. Pleasant 8.0 11.0 13.0 : <5 20 <5 <5 <5 <5
:Pine River
Alma 8.0 10.0 12.0 : <5 16 <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: 03/03/2025 - 06/01/2025
Location 95% 90% 75% 50% 25% 10% 5%
-------- ------ ------ ------ ------ ------ ------ ------
:Grand River
Jackson 10.7 11.0 12.0 12.7 13.2 13.8 14.1
:Buck Creek
Grandville 5.9 6.5 6.8 7.4 8.1 9.0 10.7
:Grand River
Eaton Rapids 3.8 3.9 4.1 4.4 4.8 5.0 5.2
Dimondale 5.9 6.1 6.7 7.6 8.4 9.3 9.6
:Red Cedar River
Williamston 5.6 5.6 5.9 6.6 7.5 8.0 8.3
East Lansing 5.0 5.0 5.4 5.9 6.6 7.5 8.2
:Sycamore Creek
Holt 5.9 6.3 7.0 7.5 8.3 8.7 9.0
:Grand River
Lansing 5.6 5.6 6.2 7.4 8.2 10.2 10.6
Grand Ledge 6.1 6.1 6.5 7.1 7.6 8.9 9.1
Portland 7.4 7.5 8.0 8.8 9.5 10.6 10.8
:Looking Glass River
Eagle 4.5 5.0 5.5 6.2 7.2 8.3 9.0
:Maple River
Maple Rapids 7.2 7.4 7.9 8.8 9.3 10.0 10.2
:Grand River
Ionia 13.5 13.6 14.8 17.3 18.9 20.6 21.5
:Flat River
Smyrna 4.1 4.2 4.7 5.0 5.6 6.7 7.0
:Grand River
Lowell 7.9 8.0 8.7 10.1 11.6 14.1 14.9
:Thornapple River
Hastings 4.2 4.3 4.8 5.4 6.6 7.5 8.2
Caledonia 4.8 4.8 5.5 6.2 7.5 9.1 9.8
:Grand River
Ada 10.9 11.1 12.1 13.9 16.0 18.4 19.1
:Rogue River
Rockford 4.6 4.8 5.1 5.9 6.6 7.7 8.3
:Grand River
Grand Rapids 6.9 7.2 9.0 10.7 13.3 16.5 17.4
:Pere Marquette River
Scottville 2.5 2.9 3.4 3.9 4.3 4.7 4.8
:White River
Whitehall 2.9 3.1 3.6 4.1 5.2 5.6 6.0
:Muskegon River
Evart 9.4 9.5 10.0 10.5 11.4 12.2 12.8
:Little Muskegon River
Morley 2.8 2.8 3.0 3.5 4.1 4.8 5.0
:Muskegon River
Croton 6.7 7.0 7.5 8.1 8.5 9.2 10.0
Newaygo 9.2 9.5 9.9 10.7 11.3 12.0 13.5
Bridgeton 10.2 10.7 11.3 12.2 13.2 14.2 15.7
:Kalamazoo River
Marshall 4.9 5.1 5.2 5.9 6.3 6.9 7.1
:Battle Creek
Battle Creek 1.2 1.4 1.5 1.8 2.1 2.4 2.6
:Kalamazoo River
Battle Creek 3.7 3.8 4.0 4.5 4.9 5.9 6.1
Comstock 4.8 4.9 5.1 6.0 6.4 7.7 8.0
New Richmond 12.6 12.7 13.4 14.1 14.6 15.7 16.2
:St. Joseph River
Burlington 4.2 4.4 4.8 5.2 5.5 6.0 6.3
:Portage River
Vicksburg 4.1 4.3 4.5 4.7 5.0 5.2 5.3
:Chippewa River
Mt. Pleasant 4.3 4.5 4.8 5.2 6.1 6.9 7.6
:Pine River
Alma 2.5 2.9 3.8 4.7 5.9 7.0 7.4
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%
-------- ------ ------ ------ ------ ------ ------ ------
:Grand River
Jackson 0.1 0.1 0.1 0.1 0.1 0.1 0.0
:Buck Creek
Grandville 0.0 0.0 0.0 0.0 0.0 0.0 0.0
:Grand River
Eaton Rapids 0.6 0.5 0.5 0.4 0.3 0.3 0.2
Dimondale 0.6 0.6 0.5 0.4 0.4 0.3 0.2
:Red Cedar River
Williamston 0.1 0.1 0.0 0.0 0.0 0.0 0.0
East Lansing 0.2 0.2 0.1 0.1 0.1 0.1 0.0
:Sycamore Creek
Holt 0.0 0.0 0.0 0.0 0.0 0.0 0.0
:Grand River
Lansing 1.0 0.9 0.8 0.6 0.5 0.4 0.4
Grand Ledge 1.0 0.9 0.8 0.7 0.5 0.4 0.4
Portland 1.1 1.0 0.8 0.7 0.6 0.5 0.4
:Looking Glass River
Eagle 0.2 0.2 0.1 0.1 0.1 0.1 0.0
:Maple River
Maple Rapids 0.2 0.2 0.1 0.1 0.1 0.1 0.0
:Grand River
Ionia 2.3 2.0 1.7 1.4 1.2 1.0 0.8
:Flat River
Smyrna 0.4 0.4 0.3 0.3 0.2 0.2 0.2
:Grand River
Lowell 3.0 2.6 2.2 1.8 1.6 1.4 1.0
:Thornapple River
Hastings 0.3 0.2 0.2 0.2 0.1 0.1 0.1
Caledonia 0.6 0.5 0.5 0.4 0.3 0.3 0.2
:Grand River
Ada 3.8 3.4 2.8 2.4 2.0 1.8 1.3
:Rogue River
Rockford 0.2 0.2 0.2 0.1 0.1 0.1 0.1
:Grand River
Grand Rapids 4.1 3.6 3.1 2.6 2.2 1.9 1.4
:Pere Marquette River
Scottville 0.7 0.6 0.6 0.5 0.5 0.5 0.4
:White River
Whitehall 0.4 0.4 0.4 0.3 0.3 0.3 0.3
:Muskegon River
Evart 0.9 0.9 0.8 0.8 0.7 0.6 0.6
:Little Muskegon River
Morley 0.1 0.1 0.1 0.1 0.1 0.1 0.1
:Muskegon River
Croton 1.8 1.7 1.7 1.6 1.4 1.2 1.1
Newaygo 1.9 1.8 1.8 1.7 1.4 1.3 1.2
Bridgeton 2.0 1.9 1.8 1.7 1.5 1.3 1.2
:Kalamazoo River
Marshall 0.2 0.2 0.1 0.1 0.1 0.1 0.1
:Battle Creek
Battle Creek 0.2 0.2 0.2 0.2 0.2 0.1 0.1
:Kalamazoo River
Battle Creek 0.7 0.7 0.6 0.5 0.4 0.4 0.4
Comstock 0.9 0.9 0.8 0.7 0.7 0.6 0.5
New Richmond 2.0 1.9 1.7 1.5 1.4 1.2 1.1
:St. Joseph River
Burlington 0.2 0.2 0.1 0.1 0.1 0.1 0.1
:Portage River
Vicksburg 0.1 0.1 0.1 0.1 0.1 0.1 0.0
:Chippewa River
Mt. Pleasant 0.3 0.3 0.2 0.2 0.2 0.1 0.1
:Pine River
Alma 0.2 0.2 0.1 0.1 0.1 0.1 0.1
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 weather.gov/grr for more weather and water
information.
The next outlook will be issued on March 13, 2025.
$$
AMD