Extended Streamflow Guidance
Issued by NWS Missouri Basin, Pleasant Hill
Issued by NWS Missouri Basin, Pleasant Hill
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SPRING FLOOD OUTLOOK
NATIONAL WEATHER SERVICE
MISSOURI BASIN RIVER FORECAST CENTER
PLEASANT HILL, MO
FEB 26, 2025
NARRATIVE PART 1 OF 1
ATTN WFO`S SERVED BY MBRFC.
This Spring Flood Outlook is not for public release until Thursday,
27 February 2025.
This Spring Outlook is for the Missouri River drainage which includes
rivers in Montana, Wyoming, Colorado, North and South Dakota,
Nebraska, Kansas, Iowa, Minnesota, and Missouri.
SPRING FLOOD OUTLOOK
Flood risk this Spring within the Missouri River basin is generally
below-normal. Some locations have a near-normal flood risk, and one
two river locations have an increased flood risk this Spring. But
on the whole, the Missouri River basin has a reduced flood risk
this Spring as compared to historical flood risk.
To provide context, a normal risk indicates that a location that
typically experiences Spring time flooding is likely to see
flooding again this year. However, a normal risk for flooding does
not necessarily mean that a location is expected to flood. For those
locations which do not typically experience flooding, a normal risk
simply indicates that flooding is again not expected this year. By
the same token, a reduced risk of flooding does not necessarily
mean that flooding is not expected, nor does an increased risk
necessarily indicate flooding is likely.
In the Spring of 2024, the Missouri River basin made a good run at
extracting itself from what was then a three-year long drought.
After good Spring 2024 precipitation over much of the area, the US
Drought Monitor for 11 June 2024 categorized less than 10 percent
of the Missouri River basin basin as being in drought. That was
the lowest percentage reported by the US Drought Monitor since June
2020. Unfortunately, the Missouri River basin soil moisture
condition has steadily worsened since June 2024, with 64% of the
basin now categorized as being in some level of drought. One could
argue we are now in our fifth year of drought as a basin.
One factor leading to today`s soil moisture deficit was the 2024
temperatures. Calendar Year 2024 was the warmest year on record
for the CONUS. Calendar Year 2024 was the second warmest year in
130 years of record for the Missouri River basin, tying Calendar
Year 1934.
Overall, mountain snowpack is near average. We are approximately
80% of the way through the normal peak snow water equivalent
accumulating period for the mountain snow, so there is still time
for conditions to change.
At the time of the writing of this Outlook, flooding is ongoing in
the mountainous west. Unseasonably warm temperatures beginning
last Friday, 21 February, and extending through the writing of this
Outlook, have resulted in the loss of one to two inches of snow
water equivalent from lower elevations across eastern Montana.
This rapid runoff, coupled with the presence of river ice, have led
to significant rises along many eastern Montana rivers. Several
reports of flooding in low-lying areas have been made. Flooding has
occurred, or currently on-going, along Big Sandy Creek near Havre
and the Musselshell River near Mosby. Clear Creek near Chinook,
the Milk River near Harlem, and the Tongue River at Miles City all
had impressive rises in stage, but did not exceed flood stage. As
temperatures remain elevated over the next few days, the risk for
ice jam formation and breakup is high, and could lead to additional
flooding.
Water supply forecasts issued in early February by the National
Weather Service project lower than average April-September runoff
volumes for all of the mountainous west. More information
regarding current Water Supply Forecasts can be accessed at
weather.gov/mbrfc/water
Over the past week, the Missouri River basin has lost most of its
widespread, but very shallow plains snow. At this time, plains
snowpack will figure little in enhancing flood risk, at least as
far as fueling runoff. However, in the absense of an insulating
snowpack, soils have been allowed to develop a fairly deep frost
depth in some areas, especially across the Dakotas. Soils, while
cold in the northern plains, are also extremely dry, and therefore
there is the presumption that northern soils may still be able to
accept some runoff when plains snow melts, or when Spring rains
fall.
River ice action has posed some problems already this winter. One
notable case being the series of ice jams which formed along the
lower Missouri River north of Omaha, Nebraska due to anomalously
cold early January temperatures. These ice jams did not raise
flooding concerns, but rather resulted in a precipitous drop in
river stage, which routed throughout the system to the mouth at
St. Louis. This low stage condition did result in two or three
power plants having to go offline due to the lack of water at
their intakes. An ice jam formed north of Omaha again in early
February, but with less impacts than the January event.
Other ice jams this season have been reported along the Madison,
Jefferson, and Tongue Rivers in Montana, the Loup and North
Platte Rivers in Nebraska; and the Shoshone River in Wyoming.
While ice jam break-up flooding risk is considered low this year,
wherever river ice remains, so does the risk for ice jam flooding.
Please note, the probabilistic quantifications that form the
basis for this Spring Flood Outlook do not take into account the
presence of river ice.
Springtime flooding in the lower one-third of the basin, including
eastern Kansas and the state of Missouri, is driven by typical
thunderstorm activity. Flooding is projected to occur again this
Spring in this region of the basin. We have already experienced
flooding in this area as recently as the first of February, where
one tributary location in eastern Kansas and two tributary
locations in the state of Missouri exceeded flood stage due to rain
falling on soils previously moistened by January snowmelt.
The following state by state flood potential discussions are based
on long-range probabilistic river outlooks developed this week.
Again, it must be stressed, these outlooks do not take into account
the presence of river ice.
In Kansas, Stranger Creek is expected to have moderate level
flooding, while the Big Blue, Black Vermillion, Little Osage and
Marias des Cygnes Rivers are projected to have minor flooding.
In the state of Missouri, the Grand, Tarkio, Platte, Crooked, and
Blackwater Rivers are outlooked to experience moderate flooding,
as do Big and Petite Saline Creeks. The Chariton, Little
Osage, Marmaton, Sac, South Grand, Lamine, Moreau, and Big Piney
Rivers are projected to see minor flooding, as does Wakenda and
Moniteau Creeks.
These projections of river stages are based on current observed
states of streamflow, soil moisture, and snowpack, coupled with
future precipitation and temperature patterns and anticipated
operational hydrologic changes such as reservoir releases and canal
diversions. "Outlooks" are provided for long-range (weeks to months)
projections based on climatological patterns of precipitation and
temperature. "Forecasts" are provided for short-term (days)
projections based on forecast patterns of precipitation and
temperature. The uncertainty of these products varies from
season to season and location to location. The uncertainty of
forecasts tend be less than the uncertainty of outlooks due to
their shorter lead time.
Users of these products are encouraged to contact their nearest
National Weather Service Forecast Office for continued updates of
meteorological conditions which can have significant impacts on
flood preparedness planning and flood fighting activities.
For additional quantitative information please refer to NWPS
products for probabilistic outlooks of potential flooding. Refer
to short-term flood forecasts and products, if any are currently
issued, for information about ongoing or near-term anticipated
flooding.
The next Spring Outlook is scheduled for release on March 13th.
Additional river information, including the monthly Water Supply
Outlook, can be accessed at the following URL:
http://weather.gov/mbrfc
Current Snow Conditions
The conditions listed below are based on observations and model
data as of Wednesday morning, February 26th.
Montana Plains
Snow depths across the eastern Montana plains are in the
2-5 inch range, with water equivalents generally less than
1.5 inch.
Wyoming Plains
Snow depths across the eastern Wyoming plains are generally less than
2.0 inches, with water equivalents less than 0.2 inches.
Colorado Plains
Little to no snow is being reported across the plains of Colorado.
Mountainous West
Snowpack conditions in the mountainous areas of the basin are
generally near to slightly below normal. In Montana, the Jefferson,
Musselshell, Missouri headwaters, Sun, Teton, and Marais River
basins are reporting a below to near normal snowpack (70-100%). The
St. Mary and Milk basins are reporting a below to near normal snowpack
(70-100%). In Wyoming, the Tongue, Bighorn, Powder, Wind, and
Yellowstone River basins are reporting a below to near normal
snowpack (75-100%). The higher elevations of the North Platte
River basin are reporting a near normal snowpack (102%). In
Colorado, the higher elevations of the South Platte River basin
are reporting a near normal snowpack (107%).
North Dakota
Snow depths across most of North Dakota range from 1-5 inches,
with water equivalents less than 1.0 inch. Higher snow totals
across northwestern North Dakota are in the 5-8 inch range with
water equivalents from 1-2 inches.
South Dakota
The Black Hills in South Dakota have 10-15 inches of snow depth
with water equivalents in the 1-5 inch range. Elsewhere across
South Dakota, little or no snow is being reported.
Iowa, Nebraska, Missouri and Kansas
No snow is being reported across Iowa, Nebraska, Missouri, and Kansas.
Current Soil Moisture Conditions
The US Drought Monitor indicates that portions of the Missouri
River basin are experiencing below normal soil moisture
conditions. Extreme drought is indicated across portions of
western North Dakota, northern and southeastern Wyoming, northwestern
Nebraska, and southwestern South Dakota. Moderate to severe drought
is indicated across eastern Montana, southern North Dakota, much
of South Dakota, Wyoming, and Nebraska, northern Kansas, western
Iowa, and southwestern Missouri.
Isolated frost depth reports suggest that soils across Montana,
Wyoming, South Dakota, and North Dakota have frost penetration
ranging from 0.5-4 feet. Frost depths of less than 1 foot
are being reported across Colorado, Kansas, Nebraska, Iowa,
and Missouri.
Current River Conditions
A large majority of rivers across the northern half of the
Missouri River basin are iced over. Generally, river levels
across the basin are currently running near to below normal, or
estimated to be so if the rivers are frozen.
A summary of river flow conditions at selected river stations for
February 26th follows:
Long Term Current
Mean (CFS) (CFS)
James River - Huron, SD 100 114 (EST)
Big Sioux River - Akron, IA 943 205 (EST)
Platte River - Louisville, NE 9230 5870 (EST)
Kansas River - Desoto, KS 5340 2050 (EST)
Gasconade River - Jerome, MO 4300 1540
Missouri River - Omaha, NE 21500 17900
Missouri River - Rulo, NE 33000 19900
Missouri River - St. Joseph, MO 36700 19500
Missouri River - Waverly, MO 47500 21700
Missouri River - Hermann, MO 83300 26400
END MBRFC
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