Early Spring Basin Conditions
HUDSON BAY DRAINAGE
SUMMARY OF PAST AND CURRENT CONDITIONS
Souris River Basin
During October and November of 2008 the eastern portion of the Souris Basin saw about 200 percent of normal precipitation. In December there was 200 to 300 percent of normal precipitation across the whole basin. January precipitation was below normal...but February precipitation 150 to 300 percent of normal.
As a result of all of this precipitation...the soils across the eastern portion of the basin were wet going into freeze-up during November and December...and continue above normal.
Currently there are between 4 and 5 inches of snow water equivalent across the basin. Snow cover has been redistributed across the landscape by the strong winds this winter. Lesser amounts can be found in open fields...while higher amounts can be found in tree rows...ditches and sheltered areas.
Devils Lake Basin
Fall and Winter precipitation across the Devils Lake basin has averaged above normal and soils across much of the basin were saturated going into freeze-up. Frost depths in eastern North Dakota remain around 2 to 3 feet...so there could be significant runoff rates especially with a rapid melt scenario.
Since the beginning of March around quarter to a half inch of precipitation fell over the Devils Lake Basin. The expectations for Devils Lake remain similar to the last outlook. Depending on the weather this Spring and Summer the Lake could rise to a level between 1450 ft and 1454 ft. The current level is about 1447 ft.
Red River of the North River Basin
Precipitation during the months of October...November...and December was much higher than normal. Even though January precipitation averaged below normal...the over trend of higher than normal precipitation continued for Febraury and the entire Winter overall.
The Palmer Drought Index for long term hydrologic conditions indicate extremely moist conditions across the Red River basin for October... through February...which is the highest wetness category in the severity index. USGS monthly-average streamflows were greater than the 90th percentile for October through February.
New snowfall occurred in the Red River basin during the last week in February and in the beginning of March...adding another half to one inch of water equivalent...and bringing snow depth reports to around one to two feet in the southern Valley. In the northern Valley snow depths average around a foot.
Snowpack densities are around 30 percent...meaning the snowpack is very dense.
Daytime temperatures are expected to warm above freezing over the weekend...with nighttime lows dropping down around 20 degrees. A slow melt can occur if the Red River Valley warms up above freezing during the day and cools off at night. This is the ideal situation given the large amount of water waiting to be released into the river system.
GREAT LAKES DRAINAGE
SUMMARY OF PAST AND CURRENT CONDITIONS:
Upper Peninsula of Michigan River Basins
Winter precipitation across Upper Michigan was generally near normal for western areas...but has been above normal for eastern and lake shore areas that have experienced numerous lake effect snows throughout the season. This has helped ease some moderate drought conditions that were mainly in western portions of this region.
Precipitation across upper Michigan from late February into early March has been below normal with generally less than a half inch of additional water equivalent. Snow depths continue to range from between 20 and 40 inches across the northern lake shore and eastern upper Michigan with water equivalents near 7 to 11 inches. Western and central portions average between 10 and 20 inches of snow with water equivalents between 3 and 6 inches.
Soil moisture continues to be below normal in the western upper peninsula while in the east it is slightly above normal. Stream flows across upper Michigan are near normal to below normal. Ice continues to cover the majority of streams and not much of the snowpack has melted yet...but given curernt conditions the outlook for spring snowmelt flooding is normal or below normal chances for flooding.
Menominee River Basin
The entire Menominee River Basin area is fairly dry according to the various drought indices. Starting in October the drought was moderate with below normal precipitation for summer and intensified to severe as this Fall also observed below normal precipitation.
Current snow depths range from 5 inches or less in the south to between 10 and 15 inches in the north. Water equivalents remain between 3 and 5 inches basin wide.
Ice continues to cover many streams in the basin. Stream flow conditions remain well below normal and chances for spring snowmelt flooding are below normal.
Northern Lower Michigan Basins
As Winter began...precipitation was more than 200 percent above normal for December. Streamflow rebounded in December due to the above normal precipitation and was rated at normal to above normal by the USGS. Since February 1 this area has seen 100 to 150 percent of normal precipitation.
Since late February precipitation between a half inch north to around one and a half inches south fell over the basin. Most of the precipitation fell as rain between March 6th and 10th. Snow water equivalents range between 2 to 2.5 inches west and 4 to 5 inches east.
Stream flow conditions range from near normal across the north to above normal across the south. Soil moisture conditions are 20 to 30 percent wetter than norma1...especially across the south. Streams are mostly free from ice.
Fall soil moisture was wetter than normal and this continued into Winter. Early snow cover protected the ground from deep frost and in early February the frost depth was only a few inches to less than a foot. Above normal temperatures...and the rainfall...since the beginning of March has depleted most if not all of the snow in the basin. Heavy rain fell across southern lower Michigan between March 7th and 11th. Rainfall amounts between 2 and 4 inches were common. The rain combined with saturated soils has lead to widespread rising of the rivers. Many locations will reach flood stage or higher during the next week.
Southern Lower Michigan Basins
Southeastern Lower Michigan Streams
Fall soil moisture was wetter than normal and this continued into Winter. Early snow cover protected the ground from deep frost and in early February the frost depth was only a few inches to less than a foot.
Above normal temperatures...and the rainfall...since the beginning of March has depleted most if not all of the snow in the basin.
Heavy rain fell across southern lower Michigan between March 7th and 11th. Rainfall amounts between 2 and 4 inches were common. The rain combined with saturated soils has lead to widespread rising of the rivers. Many locations will reach flood stage or higher during the next week.
Grand Kalamazoo St. Joseph Saginaw and White River Basins
Flows have been generally above normal to much above normal at many locations in this region since September according to the USGS. This is due to above average monthly precipitation since September...which was between 125 to 150 percent of normal.
Streamflows...due to the moist soils and the melting of the snow continues above normal for this time of year.
Very little snow remains on the ground after recent warm temperatures and rainfall...except for around 6 inches of depth with 1 to 2 inches of water equivalent in northern portions of the Muskegon River basin.
Eastern Wisconsin Streams
Fall precipitation was below of normal for northern and central locations ...and slightly above normal in the far southeastern section of Wisconsin. Winter precipitation averaged above normal...especially due to wetter than normal December. Cold weather from December into January produced quite a bit of ice in area rivers and streams...but recent milder weather and rain in early February through March removed much of the ice from the Root River in the south.
Mid February warming caused some flooding for locations experiencing rapid snowmelt and some ice action. More recently heavy rain fell across the eastern Wisconsin streams during the period from March 6th to 10th. This has caused another round of minor flooding in the far southeastern basins....mainly the Root...the Milwaukee...and the Sheybogan...from March 7th to the 9th. The rain...a little snowmelt and ice action contributed to the flooding.
Little snow remains across the southern third of the basin while across the northern two-thirds between 6 and 12 inches are still on the ground. Waterequivalents between 2 and 3 inches north drop to zero in the south.
Western Lake Superior Streams
There has been little change in the western Lake Superior streams. Streamflows are in the normal range for this time of year...with most rivers remaining ice affected.
Precipitation since the end of February generally was around a half inch water equivalent. It fell as snow. Our model shows snow water equivalents between 2.5 inches and 5 inches on the Minnesota side and 2.0 to 3.5 inches on the Wisconsin side.
UPPER MISSISSIPPI RIVER DRAINAGE
SUMMARY OF PAST AND CURRENT CONDITIONS:
TRIBUTARIES TO THE MISSISSIPPI RIVER
Minnesota Tributaries to the Mississippi River
Minnesota River Basin
A significant gradient in soil moisture exists in the Minnesota River Basin at this time. Based on modeled soil moisture conditions from the MRCC...the far western portions of Minnesota are experiencing up to 20 percent wetter conditions through the soil profile compared to average. Far eastern portions of the basin show up to 20 percent drier conditions.
The late February warmup did reduce the snowpack via sublimation...local melt...and some streamflow response...however much of the water is still believed to be locked up above the frozen ground as ice in ditches and low lying areas across the basin. In March a few snow storms have increased snow depth from 6 to 12 inches in the upper half of the basin to 1 to 3 inches across the lower half. NCRFC modeled snow water equivalents range 2 to 4 inches in the west to 1 inch or less in the eastern portions.
Streamflow conditions from September to November were normal...and increased to the above normal range according from December through current.
Current frost depths are greater than 2 feet in the headwaters.
There has been no significant flood or streamflow activity this winter and all areas are well below flood stage.
Wisconsin Tributaries to the Mississippi River
Chippewa River Basin
March precipitation so far continued the below normal trend. Current snow depths are 6 to 12 inches across the northern parts of the basin and 1 to 3 inches across the southern portion. Water equivalents range from 2 to 4 inches north to 1 to 2 inches south.
The U.S. Drought Monitor still show the CHP in moderate to severe drought and our outlooks indicate below normal chances for spring flooding in the area.
Wisconsin River Basin
Snow cover ranges from 0 to 3 inches in the lower half of the basin to between 6 and 11 inches of snow depth in the upper half. In the upper half of the basin snow water equivalents are 1 to 3 inches and around an inch or less in the lower portion.
Because of the lack of a heavy snowpack and the low levels of the reservoirs...most of the Wisconsin River has only a very slight chance of reaching flood levels. The lower portion of the Kickapoo River has near normal probabilities of reaching flood level while the upper part of the Kickapoo...along with the Trempeleau...Black...La Crosse ...and Baraboo Rivers have lower than normal probabilities of reaching flood level.
Iowa Tributaries to the Mississippi River
Cedar and Iowa River Basins
Since the beginning of the year precipitation has been about 55 percent of normal. Despite lack of significant Winter precipitation...the recent melt of the snow that was there has increased the soil moisture conditions in the southern half of the basin.
Currently...the lower Iowa and many tributary locations are above flood stage due to rainfall on March 7th to 11th. Some locations above Moderate or even Major flood levels. Because of the downstream flooding... Coralville Dam has reduced outflow and the pool elevation is climbing.
There is no snowpack remaining in this basin. Primarily because of the current high water levels...the probabilities of reaching flood stage are either near normal or greater than normal for the lower Iowa River ...from Marengo down and either near normal or eight to 13 percent lower than normal for other locations.
Skunk Maquoketa and Wapsipinicon River Basins
The Skunk River Basin had a wetter than normal Fall...with up to 150 percent of normal precipitation. The Maquoketa and Wapsipinicon River Basins had near normal to slightly above normal precipitation.
Soils are saturated and current streamflows continue above normal since October. Many locations throughout the forecast group have been experiencing minor to moderate flooding due to heavy rainfall from March 7th to 11th.
Des Moines River Basin
Precipitation during October and November 2008 was fairly typical for this area... although December had wetter than normal conditions.
Current stream flows continue well above normal.
Due to heavy rainfall March 7th to 11th...minor flooding is occurring in the Des Moines River basin. Many southern tributaries crested above flood stage and the Des Moines River at Saint Francisville crested just under moderate flood levels on March 9th.
Soils are saturated at this point...until we get a dry spell for a couple of weeks...any additional rainfall may cause local rivers and streams to rise.
Illinois Tributaries to the Mississippi River
Illinois River Basin
Since March 1st...much of this area has received between 300 to 400 percent of normal precipitation due to heavy rains of 3 to 5 inches over a 4 day period beginning March 7th. The Illinois River and many of its tributaries are now experiencing Moderate to Major flooding with a few locations nearing flood of record on the Kankakee River and Iroquois River basins. Rivers are still rising at many locations. The crest on the Mainstem Illinois River is at La Salle.
Rock River Basin
Streamflow conditions remain well above normal for this time year....as it has been across the Rock River basin for much of the Fall and Winter.
Heavy rains at the end of February and this past week have eliminated the snow cover and caused flooding throughout the basin. Moderate flooding has been occurring across much of the basin...and major flooding from Joslin to Moline.
Kaskaskia and Big Muddy River Basins
The Kaskaskia and Big Muddy River Basins in southern Illinois had a wetter than normal Fall due in part to heavy rains at the beginning of September as remnants of Hurricane Gustav passed through the region. Winter precipitation averaged near normal to slightly above.
Overall current streamflows are slightly above normal. The upper part of the Kaskaskia River has 130 percent of the normal flow. and Carlyle Reservoir remain well above normal due to controlled releases of the February storm water.
At present time there is no snow cover and the streams are ice free.
Missouri Tributaries to the Mississippi River
Fabius Fox Salt and Cuivre River Basins
Northeast Missouri began Fall with wet antecedent conditions following an unusually wet summer. December 2008 precipitation was a little above normal but November 2008...January and February precipitation has been near or a little below normal. USGS streamflows started the Fall running above normal to much above normal...but have slowly recessed to the normal or slightly above normal range.
Heavy rains since March 1st caused widespread minor and moderate flooding in the basin with crests around the major level on the North and Middle Fabius Rivers. This continues the wet antecedant conditions that have been in place since last summers major floods. Thus there is an elevated risk for minor and moderate floods during the next three months. The risk for major flooding remains near historical probabilities however....due to the steep terrain of the watersheds... large flood events in these basins tend to be based more on rainfall intensity and rapid runoff from steep terrain and are less a function of antecedant soil conditions.
Meramec River River Basin
Winter precipitation averaged around normal to slightly above...while totals so far in March are around 50 percent of normal.
Soil moisture conditions are generally only slightly above normal.
Some minor flooding occurred across the basin after a mid-February rain event. Since then streamflows have returned to normal conditions.
There is no snow cover in the basin at this time.
Mississippi River Mainstem
Mississippi River from the Headwater Area to Red Wing MN
The Upper Mississppi River basin has had near normal Fall and Winter precipitation. Since March 1st...this area has received between 100 to 125 percent of normal with the higher amounts falling in the headwater area.
After recent snowfall in March snow depths range from 12 to 24 inches across the northern half of the basin...with water equivalents around 3 to 4.5 inches. For the southern half snow depths average 2 to 6 inches with water equivalents around 0.3 to 2 inches.
Average streamflows were normal for Fall and slightly above normal for Winter. The Headwaters of the Mississippi River are not as dry as last year....so the Palmer Drought Index now has the upper Mississippi River in the normal range....with normal soil moisture condition.
The more northern areas in the headwaters with more snow cover remaining show slightly above normal chances for Spring flooding.
Mississippi River from Lake City MN to Lock/Dam 10 at Guttenberg IA
In December..this area received between 175 to 200 percent of normal precipitation...around 50 percent of normal in January and between 75 and 100 percent of normal in February. So far in March...this region has received between 100 to 125 percent of normal precipitation.
Streamflows in December through February were above average in the 76 to 90th percentile. The Iowa portion increased in February to above normal streamflow at greater than 90 percent according to the USGS. Current March streamflows aer above normal flows for most locations.
The Palmer Drought Index is showing this area to be average for the most part with the exception for the northeastern part of Iowa which has more moisture and is in the very moist class. The Climate Prediction Center indicates normal soil moisture for most of the area with the southern part of Minnesota and northeastern Iowa to be about 150 percent of normal.
NCRFC modeled snow water equivalents generally less than a half inch in southeastern Minnesota and southwestern Wisconsin.
When comparing the exceedence probability plots for maximum stage during the current probabilistic forecast for the period of the conditional simulations in all areas show below normal chance of reaching flood stage during this period versus historical simulations.
Mississippi River from Lock/Dam 11 at Dubuque IA to Dam 22 at Saverton MO
The MRCC shows Winter precipitation for this area was running a good 175 to 250 percent of normal. Then January 2009 was actually fairly dry...running from 75 percent of normal north to only 25 percent of normal south...with February returning to near normal precipitation. Since March 1st...precipitation has been between 200 to 400 percent of normal.
Minor to moderate flooding is currently occurring or forecast from about Muscatine Iowa southward due to heavy rains that fell in nearby areas of Iowa...Illinois...and northeastern Missouri from March 7th through March 11th.
USGS statistics indicate well above normal flows are being reported for many of the tributaries to the mainstem stretching all the way from Dubuque down to Gregory Landing.
When comparing the exceedence probability plots for maximum stage during the current probabilistic forecast for the period of March 17th to June 15th...the conditional simulations show an equal or less chance of reaching flood stage during this period versus historical simulations. The exception in the group is Gregory Landing MO on the Mississippi River where its chances of reach flood stage are greater when compared to the historical simulation by about 20 percent
Mississippi River from Louisiana to Chester IL
For January the lower end of the Mississippi has been about 80 percent above normal streamflow. Baseflow conditions from the major contributing rivers to this portion of the Mississippi River such as the Missouri River...Illinois River and the upper Mississippi River have all been above normal for the last month.
Rain and melt in December created run of the river Mississippi conditions but with the well below normal January precipitation the Mississippi River had been allowed to recede to the current mean flow states for early February.
Heavy rain upstream has continued to create higher than normal stream flow for the MIS with the melt rise for the upper mis yet to come.
When comparing the exceedence probability plots for maximum stage... the current probabilistic forecast for the period of March 17th to June 15th ...show little difference between conditional and historic simulations for most segments in this portion on the MIssissippi River.
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