SPRING FLOOD OUTLOOK
NATIONAL WEATHER SERVICE
MISSOURI BASIN RIVER FORECAST CENTER
PLEASANT HILL, MO
MAR 06, 2019
NARRATIVE PART 1 OF 1
ATTN WFO'S SERVED BY MBRFC.
This Outlook is not for public release until Wednesday, March 6, 2019.
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 varies across the Missouri River basin. Spring
flood risk is greatly enhanced in the east, including eastern South
Dakota, eastern Nebraska and western Iowa, eastern Kansas and across
the state of Missouri. The rest of the Missouri River basin has a near
normal risk for flooding, as compared to historic normals.
A normal risk indicates that a location that typically experiences
Spring time flooding may flood again this year. A normal risk for
flooding does not necessarily mean that a location will flood,
however. 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. An
increased risk does not necessarily indicate flooding is likely.
Mountain snowpack overall is near normal. Widespread, significant
flooding in the mountainous west is not likely due to mountain
snowmelt alone.
Plains snowpack is widespread. Highest amounts are located along the
northern and eastern boundary of the Missouri River basin, extending
from northern Montana, through north-central North Dakota, southward
into eastern South Dakota. Plains snowpack plays a significant role
in the much above normal flood risk that currently exists in the
eastern portion of the Missouri River basin. The presence of
wetter than normal soils over most of the plains area, and the
presumed frozen ground condition over the entire northern plains area,
also are key factors in this outlook.
Springtime flooding in the lower one-third of the basin, including
southern Iowa, 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.
The following state by state flood potential discussions are based
on long-range river outlooks developed this week.
Minor flooding is expected along the Milk River in Montana.
Minor flooding is expected along the Cannonball River in North Dakota.
Little Muddy and Spring Creeks in North Dakota may also see minor
flooding this Spring.
Moderate level flooding is likely along the Rock River in Minnesota.
Minor flooding is projected to occur along Skunk. Firesteel, and
Turtle Creeks in South Dakota. The East Fork Vermillion River, and
the Bad and Little Missouri Rivers are also expected to experience
minor flooding. Moderate level flooding is likely on the White,
Grand, and Moreau Rivers in South Dakota. Major flooding is expected
along the James, Vermillion, and Big Sioux Rivers, and on Split Rock
Creek.
Minor flooding is expected along Turkey, Salt, and Beaver Creeks in
Nebraska. The West Fork Big Blue, Little Blue, South Loup, Loup, and
Little Nemaha Rivers are all projected to experience minor flooding
this Spring. Minor flooding is expected on the lower reach of the
North Platte River. Moderate level flooding is likely along the Big
Blue, Elkhorn, and Platte Rivers; as well as on Lincoln, Maple, Wahoo,
and Ponca Creeks in Nebraska. Major level flooding is expected along
the North Fork Elkhorn and Wood Rivers, and on Logan and Shell Creeks.
In Iowa, minor flooding is expected on the West Branch Floyd River.
Moderate level flooding is projected for the West Nishnabotna, East
Nishnabotna, and Nishnabotna Rivers, as well as along the West Fork
Ditch. Major level flooding in Iowa is projected for the Floyd,
Little Sioux, Ocheyedan, Rock, and Big Sioux Rivers.
Kansas streams likely to experience minor flooding this Spring include
the Little Blue, Big Blue, Black Vermillion, Delaware, Republican,
Marais des Cygnes, and South Fork Solomon Rivers. Minor flooding is
also possible in the lower section of the Kansas River. Minor
flooding is also projected along Chapman, Mill, Buffalo, Salt (in the
Smoky Hill basin), Mulberry, Salt (in the Marais des Cygnes basin),
and Bow Creeks. Moderate level flooding in Kansas is expected along
the Vermillion, North Fork Solomon, Solomon, Saline, Smoky Hill, and
Little Osage Rivers, as well as on Mill and Stranger Creeks.
The Chariton, Moreau, Big Piney, Gasconade, Little Osage, Marmaton,
and Osage Rivers in Missouri are projected to have minor flooding.
Minor flooding is likely along Moniteau, and Petite Saline Creeks.
The Grand, Crooked, Blackwater, Lamine, Sac, South Grand, 102, and
Platte Rivers are expected to have moderate level flooding, as does
Wakenda Creek in Missouri. The Tarkio River is likely to experience
major flooding this season.
The Missouri River itself is projected to experience moderate flooding
in the reach downstream of Gavins Point Dam.
Freeze-up ice jamming has already been reported at many
locations this winter. However impacts have been relatively minor
and localized in extent. Ice formation has been reported along
reaches of the North Platte, Elkhorn, Niobrara, Middle Loup, Cedar,
and Platte Rivers in Nebraska, the Wind River in Wyoming, and the
Jefferson, Madison, and Missouri Rivers in Montana. Break-up ice jam
flooding is highly likely as persistant cold temperatures continue
to hold onto and build river ice, all the while the calendar continues
to move later and later into the season. Rain and late season
snowmelt is likely to occur while rivers remain ice covered.
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 AHPS products
for probabilistic outlooks of potential flooding. Refer to flood
forecasts and products, if any are currently issued, for information
about ongoing or near-term anticipated flooding.
This is the last scheduled Spring Outlook of the season. If
significant changes occur subsequent to this Outlook, additional
Outlooks can be released to address needs.
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, March 6.
Montana Plains
Snow depths across northeastern Montana range from 10-15 inches,
with maximum water equivalents in the 1-3 inch range. Across
southeastern Montana, snow depths are generally less
than 10 inches with water equivalents of less than 2 inches.
Wyoming and Colorado Plains
There is very little snow being reported in the plains of Wyoming
and Colorado. Snow depths are less than 4 inches with water
equivalents less than half an inch.
Mountainous West
Snowpack conditions in the mountainous areas of the basin are generally
near to above normal. In Montana, the Jefferson, Musselshell,
Missouri headwaters, Sun, Teton, Marais, St. Mary, and Milk River
basins are reporting a near normal snowpack (90-110%). Due to recent
heavy snow, the Tongue, Bighorn, Powder, Wind, and Yellowstone River
basins are reporting a near to above normal snowpack (100-130%). The higher
elevations of the North Platte River basin are reporting a near to above
normal snowpack (100-120%). In Colorado, the higher elevations of
the South Platte River basin are reporting an above normal
snowpack (110-130%).
North Dakota
The western portion of North Dakota has snow depths ranging from
7-12 inches with water equivalents in the 1-3 inch range. The central and
eastern portions of the state have received more snow with depths in the
12-18 inch range and water equivalents in the 2-5 inch range.
South Dakota
The Black Hills in South Dakota have 15-30 inches of snow depth
with water equivalents in the 4-8 inch range. Elsewhere across
South Dakota, there is a wide range of snow depths. The northeastern
portion of South Dakota is reporting 15-20 inches of snow with
water equivalents in the 3-5 inch range with isolated reports in excess
of 5 inches. The northwestern and north-central portion of the state have
snow depths in the 10-16 inch range with water equivalents in the
1-4 inch range. Snow depths across the southern portion of South Dakota
are generally less than 8 inches with water equivalents less than 2 inches.
Iowa
Snow depths of 10-15 inches are being reported across western
Iowa with water equivalents in the 1-3 inch range.
Nebraska
Recent storms have increased the snow depths across eastern Nebraska into
the 6-10 inch range with water equivalents generally less than 2 inches.
Across western Nebraska, snow depths are less than 6 inches with water
equivalents of less than 1 inch.
Missouri
Snow depths across northwestern Missouri are in the 4-6 inch range with water
equivalents generally less than 1.5 inches. Elsewhere across the state,
snow depths are generally less than 3 inches with water equivalents
less than half an inch.
Kansas
Snow depths across most of Kansas are in the 2-4 inch range with water equivalents
less than 1.5 inches. Higher depths in the 4-8 inch range are being reported
across north-central Kansas with water equivalents in the 1-2 inch range.
Current Soil Moisture Conditions
The US Drought Monitor indicates much of the Missouri River basin
is experiencing near to above normal soil conditions. There are a couple
areas of drought remaining. Abnormally dry conditions are indicated
across central Wyoming. Abnormally dry to moderate drought is also
indicated across portions of central and northeastern Colorado.
Isolated frost depth reports suggest that soils across Montana, Wyoming,
and North Dakota have frost penetration ranging from 2-4 feet. Frost
depth reports across South Dakota, Nebraska, and Iowa range
from 1-3 feet. Frost depths of less than 1 foot are being reported
across Colorado, Kansas, and Missouri.
Current River Conditions
The majority of the rivers in the northern two-thirds of the basin are
iced over. Generally, river levels in this portion of the basin are
currently running near to above normal, or estimated to be so if the
rivers are frozen. In the southern third of the basin, rivers are also
running near to above normal with the exception of central Colorado
where flows are below historical medians.
A summary of river flow conditions at selected river stations for
March 6 follows:
Long Term Current
Mean (CFS) (CFS)
James River - Huron, SD 146 72 (EST)
Big Sioux River - Akron, IA 1810 1100 (EST)
Platte River - Louisville, NE 8360 10900 (EST)
Kansas River - Desoto, KS 2920 5200
Gasconade River - Jerome, MO 2040 2790
Missouri River - Omaha, NE 20300 23200
Missouri River - Rulo, NE 30800 33300
Missouri River - St. Joseph, MO 34500 38600
Missouri River - Waverly, MO 42900 50300
Missouri River - Hermann, MO 72100 95000
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