Extended Streamflow Guidance
Issued by NWS Missouri Basin, Pleasant Hill
Issued by NWS Missouri Basin, Pleasant Hill
Versions:
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SPRING FLOOD OUTLOOK
NATIONAL WEATHER SERVICE
MISSOURI BASIN RIVER FORECAST CENTER
PLEASANT HILL, MO
FEB 12, 2025
NARRATIVE PART 1 OF 1
ATTN WFO`S SERVED BY MBRFC.
This Spring Flood Outlook is not for public release until Thursday,
13 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 varies from
near-normal to below-normal. No areas have an above-normal risk for
flooding this Spring.
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 69% 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 Calendary Year
1934.
Overall, mountain snowpack is below average. Flooding in the
mountainous areas due to snowmelt is not likely this year. We are
approximately 70% of the way through the normal peak snow water
equivalent accumulating period for mountain snow, so there is still
time for conditions to change.
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
There is widespread, but very shallow plains snow stretching aross
the northern half of the Missouri River basin. At the time of
writing this Oulook, a system is currently producing plains snow
across the lower basin as well. 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.
Other ice jams this season have been reported along the Madison
and Jefferson Rivers in Montana, the Loup and North Platte Rivers
in Nebraska; and the Shoshone River in Wyoming. No significant
flooding was reported being associated with these jams. While ice
jam break-up flooding 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, Sac, Tarkio, Platte,
Crooked, and Blackwater Rivers are outlooked to experience moderate
flooding, as do Big and Petite Saline Creeks. The Chariton, Little
Osage, Marmaton, South Grand, Lamine, Moreau, and Big Piney Rivers
are projected to see minor flooding, as does Wakenda and Moniteau
Creeks. The Missouri River downstream of Kansas City to the mouth
is also likely to see minor flooding.
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 February 27th.
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 12th.
Montana Plains
Snow depths of 3-6 inches are being reported across the plains
of eastern Montana, with water equivalents generally less than
1.5 inch.
Wyoming Plains
Snow depths across northeastern Wyoming range from 4-8 inches, with
water equivalents generally less than 1.5 inches. Elsewhere across
eastern Wyoming, snow depths are generally less than 2.0 inches with
water equivalents less than 0.2 inches.
Colorado Plains
Snow depths of less than 1.0 inch are being reported across the plains
of Colorado with water equivalents less than 0.1 inches.
Mountainous West
Snowpack conditions in the mountainous areas of the basin are
generally below normal. In Montana, the Jefferson, Musselshell,
Missouri headwaters, Sun, Teton, and Marais River basins are
reporting a below normal snowpack (60-90%). The St. Mary and Milk
basins are reporting a below normal snowpack (70-90%). In Wyoming,
the Tongue, Bighorn, Powder, Wind, and Yellowstone River basins are
reporting a below to near normal snowpack (85-105%). The higher
elevations of the North Platte River basin are reporting a slightly
below normal snowpack (91%). In Colorado, the higher elevations of
the South Platte River basin are reporting a near normal
snowpack (98%).
North Dakota
Snow depths from 2-6 inches are being reported across most of
North Dakota with water equivalents less than 1.0 inch. Higher
snow depths from 6-9 inches are being reported in the upper
portion of the James basin in the eastern half of North Dakota.
Water equivalents in this area are in the 1-2 inch range.
South Dakota
The Black Hills in South Dakota have 10-15 inches of snow depth
with water equivalents in the 1-4 inch range. Elsewhere across
South Dakota, snow depths are generally less than 3 inches with
water equivalents less than 0.5 inches.
Iowa
Snow depths across western Iowa are generally less than 3 inches with
water equivalents less than 0.3 inches.
Nebraska, Missouri and Kansas
A storm system is currently producing snowfall across Nebraska,
Missouri, and Kansas. Snow depths are currently 1-3 inches with
water equivalents less than 0.5 inch.
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 0.5-3 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 12th follows:
Long Term Current
Mean (CFS) (CFS)
James River - Huron, SD 79 118 (EST)
Big Sioux River - Akron, IA 600 212 (EST)
Platte River - Louisville, NE 7210 5210 (EST)
Kansas River - Desoto, KS 4110 2650
Gasconade River - Jerome, MO 2510 1370
Missouri River - Omaha, NE 19900 17830 (EST)
Missouri River - Rulo, NE 28600 23200
Missouri River - St. Joseph, MO 31200 25200
Missouri River - Waverly, MO 37600 28800
Missouri River - Hermann, MO 61500 42100
END MBRFC
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