Second Spring Flood Outlook Released March 7
The second 2008 Spring Flood Outlook was released March 7, 2008 and indicates a high flood potential for streams across northern Illinois and northwest Indiana this Spring. The area of greatest concern for snowmelt flooding includes the Rock, Pecatonica, and upper Fox rivers in northern Illinois. Moderate to major flooding is possible along portions of the Rock and Pecatonica rivers. In addition, due to the already saturated conditions, flooding will continue on the Kankakee River in northwest Indiana.
The complete report can be viewed below.
We also urge those with river interests to view our Advanced Hydrologic Prediction Service (AHPS) web pages, for the latest river stages and river forecasts and probabilistic flood outlook information.
The amount or severity of spring flooding depends on the following factors:
- Current snow depth
- Liquid equivalent of the snow
- Current river levels and streamflow
- Melting rate (how fast the snow melts)
- Future precipitation
- Soil moisture and frost depth
- Ice jams (can lead to flash flooding)
Additional Spring Flood Outlook information is available from the North Central River Forecast Center.
FGUS73 KLOT 071527 ESFLOT ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019- 082000- HYDROLOGIC OUTLOOK NATIONAL WEATHER SERVICE CHICAGO IL 930 AM CST FRI MAR 7 2008
...SPRING FLOOD AND WATER RESOURCES OUTLOOK NUMBER 2... ...RISK OF MODERATE TO MAJOR FLOODING ON SOME RIVERS THIS SPRING...
THE POTENTIAL FOR FLOODING IS HIGH THIS SPRING ON MANY STREAMS IN NORTHERN ILLINOIS AND NORTHWEST INDIANA DUE TO WELL ABOVE NORMAL PRECIPITATION THIS PAST WINTER. MODERATE TO MAJOR FLOODING IS POSSIBLE ON PORTIONS OF THE ROCK AND PECATONICA RIVERS WITH MODERATE FLOODING LIKELY ON THE UPPER FOX RIVER.
THIS SPRING FLOOD AND WATER RESOURCES OUTLOOK IS FOR STREAMS IN THE DES PLAINES...FOX...LITTLE CALUMET...AND KANKAKEE RIVER BASINS IN NORTHEAST ILLINOIS AND NORTHWEST INDIANA INCLUDING THE ILLINOIS RIVER DOWN TO LA SALLE. THIS OUTLOOK ALSO INCLUDES STREAMS IN THE ROCK RIVER BASIN INCLUDING THE PECATONICA AND KISHWAUKEE RIVERS AS WELL AS THE ROCK RIVER FROM ROCKTON TO DIXON ILLINOIS. THIS OUTLOOK IS ISSUED IN ADDITION TO THE 7 DAY RIVER FORECASTS THAT ARE ISSUED WHEN RIVER FORECAST LOCATIONS ARE IN FLOOD OR FORECAST TO RISE ABOVE FLOOD STAGE.
...CURRENT SNOW COVER AND LIQUID WATER EQUIVALENT... SNOWFALL WAS WELL ABOVE NORMAL THIS PAST WINTER OVER PORTIONS OF THE ROCK...FOX...AND UPPER DES PLAINES WATERSHEDS. RECORD AMOUNTS OF SNOWFALL WERE RECORDED AT ROCKFORD ILLINOIS. WARM TEMPERATURES LAST WEEKEND INITIATED SOME SNOWMELT AND RUNOFF... HOWEVER RECENT COLD TEMPERATURES TEMPORARILY HALTED THE MELT. CURRENT SNOW DEPTHS RANGE GENERALLY BETWEEN 2 AND 4 INCHES OVER PORTIONS OF NORTHERN ILLINOIS ALONG AND NORTH OF I-88 WHICH INCLUDES THE UPPER ROCK...FOX...AND DES PLAINES WATERSHEDS. A DEEPER SNOWPACK REMAINS IN THE HEADWATERS AREA OF THE ROCK AND FOX RIVER WATERSHEDS IN SOUTHERN WISCONSIN.
WATER EQUIVALENTS OF THE SNOWPACK RANGED BETWEEN 1 AND 3 INCHES IN ILLINOIS. WATER EQUIVALENTS WERE AS HIGH AS 4 TO 6 INCHES IN THE HEADWATERS AREA OF THE ROCK RIVER BASIN IN WISCONSIN. REPORTS FROM NWS COOPERATIVE OBSERVERS ALSO INDICATED A SIGNIFICANT AMOUNT OF ICE BENEATH THE SNOW COVER.
...SOIL CONDITIONS AND FROST DEPTHS... SOIL MOISTURE REMAINS ABOVE NORMAL DUE TO RECENT RAIN AND SNOWMELT...ESPECIALLY OVER THE KANKAKEE RIVER BASIN. PRECIPITATION DURING THE LAST 90 DAYS OVER THE KANKAKEE RIVER BASIN HAS BEEN GREATER THAN 200 PERCENT OF NORMAL IN SOME LOCATIONS. FROST DEPTHS RANGED BETWEEN 4 AND 12 INCHES IN SOME LOCATIONS OF FAR NORTHERN ILLINOIS.
...RIVER CONDITIONS... FLOODING CONTINUES ON THE UPPER DES PLAINES...ILLINOIS...AND KANKAKEE RIVERS FROM A COMBINATION OF RAIN AND SNOWMELT. INCREASED FLOWS FROM SNOWMELT BEGAN TO BREAKUP THE ICE COVER ON THE ROCK RIVER AND RESULTED IN SOME ICE JAMS. ICE JAMS ARE STILL POSSIBLE ON PORTIONS OF THE ROCK RIVER...ESPECIALLY WITHIN OGLE AND LEE COUNTIES AND AREAS DOWNSTREAM. WATER LEVELS CAN RISE SEVERAL FEET IN ONLY A MATTER OF MINUTES WHEN AN ICE JAM FORMS. THE DES PLAINES...LOWER FOX...AND KANKAKEE RIVERS WERE MOSTLY FREE OF ICE WITH THE EXCEPTION OF SCATTERED AREAS OF SHORE ICE.
...WEATHER OUTLOOKS... THE 6 TO 10 DAY OUTLOOK INDICATES BELOW NORMAL TEMPERATURES AND SLIGHTLY ABOVE NORMAL PRECIPITATION OVER THE NORTHERN THIRD OF ILLINOIS. NORMAL HIGH TEMPERATURES FOR THIS PERIOD RANGE FROM THE LOW TO MID 40S. NORMAL LOW TEMPERATURES ARE IN THE MID TO UPPER 20S. THE 30 DAY OUTLOOK INDICATES A CHANCE OF ABOVE NORMAL PRECIPITATION...ESPECIALLY OVER THE KANKAKEE RIVER BASIN... AND NEAR NORMAL TEMPERATURES. THE 90 DAY LONG-RANGE PROBABILISTIC OUTLOOKS INDICATE MAINLY EQUAL CHANCES OF ABOVE AND BELOW NORMAL TEMPERATURES AND PRECIPITATION.
...FLOOD POTENTIAL SUMMARY... BASED ON CURRENT HYDROLOGIC CONDITIONS INCLUDING THE CURRENT SOIL MOISTURE...SNOWPACK...AND STREAMFLOW CONDITIONS...THERE IS A RISK OF MODERATE TO MAJOR FLOODING THIS SPRING ON THE ROCK AND PECATONICA RIVERS. MODERATE FLOODING IS POSSIBLE ON THE UPPER FOX RIVER WITH MINOR FLOODING EXPECTED ON THE DES PLAINES RIVER. MODERATE FLOODING IS ALSO EXPECTED ON THE KANKAKEE RIVER IN INDIANA. IT SHOULD BE NOTED THAT HYDROLOGIC CONDITIONS CAN CHANGE RAPIDLY DURING LATE WINTER AND EARLY SPRING. AN IDEAL MELT PERIOD WOULD INCLUDE ABOVE FREEZING TEMPERATURES DURING THE DAY AND BELOW FREEZING AT NIGHT WITH NO ADDITIONAL RAIN OR SNOW. THIS WOULD ALLOW FOR A MORE TIMED RELEASE OF RUNOFF INTO THE STREAMS. A PERIOD OF HEAVY RAIN DURING THE MELT PERIOD WOULD LIKELY RESULT IN MORE SIGNIFICANT FLOODING.
THE VALUES IN THE TABLE BELOW ARE VALID MAR 5 TO JUN 5 2008 IN THE
TABLE BELOW...THE 90 THROUGH 10 PERCENT COLUMNS INDICATE THE CHANCE
THAT A LOCATION ON A RIVER COULD RISE ABOVE THE LISTED STAGE LEVELS
IN THE NEXT 90 DAYS. FOR EXAMPLE: THE ROCK RIVER AT ROCKTON HAS A
FLOOD STAGE OF 10 FEET. WITHIN THE NEXT 90 DAYS...THERE IS A 50 PERCENT
CHANCE THE RIVER WILL RISE ABOVE 14.3 FEET.
LOCATION FS (FT) 90% 80% 70% 60% 50% 40% 30% 20% 10% -------- ------- --- --- --- --- --- --- --- --- --- KANKAKEE RIVER DUNNS BRIDGE 10.0 9.9 10.4 11.1 11.3 11.5 11.6 12.0 12.1 12.4 KOUTS 11.0 10.9 11.2 12.0 12.3 12.6 12.7 13.3 13.6 14.1 SHELBY 9.0 10.6 10.8 11.3 11.5 11.9 12.3 12.6 13.0 13.1 MOMENCE 5.0 3.8 4.0 4.4 4.9 5.1 5.4 5.6 6.3 7.2 WILMINGTON 6.5 3.7 4.3 4.6 5.0 5.3 5.7 5.9 6.6 7.4 IROQUOIS RIVER IROQUOIS 18.0 15.3 16.6 17.6 18.3 19.3 20.8 21.5 22.5 23.4 CHEBANSE 16.0 9.5 10.0 10.4 11.1 11.9 12.6 13.4 13.8 15.5 DES PLAINES RIVER RUSSELL 7.0 7.1 7.2 7.5 7.6 7.7 7.8 7.9 8.0 8.5 GURNEE 7.0 6.0 6.4 6.9 7.2 7.3 7.7 7.9 8.2 9.4 DES PLAINES 5.0 3.5 3.8 4.2 4.6 4.9 5.4 6.2 6.8 8.0 RIVERSIDE 7.0 5.5 5.7 6.1 6.4 6.6 6.8 7.0 7.2 7.9 FOX RIVER ALGONQUIN 3.0 3.0 3.1 3.2 3.4 3.5 3.6 3.7 3.9 4.3 DAYTON 12.0 9.9 10.7 11.3 12.1 12.5 13.0 13.3 13.6 14.3 VERMILION RIVER PONTIAC 14.0 7.0 7.7 8.6 9.6 10.3 11.1 12.1 13.4 15.8 LEONORE 16.0 10.4 11.4 13.3 14.2 15.2 16.4 17.0 18.5 20.9 THORN CREEK THORNTON 10.0 5.7 7.0 7.5 8.3 8.7 9.2 9.4 9.9 10.6 LITTLE CALUMET RIVER MUNSTER 12.0 7.5 7.9 8.1 8.3 8.6 8.8 9.1 9.8 10.9 SOUTH HOLLAND 16.5 9.2 10.6 11.1 11.7 12.0 12.7 13.3 13.9 14.1 ILLINOIS RIVER MORRIS 16.0 10.4 11.8 14.2 15.1 15.9 16.9 17.7 19.2 20.1 LA SALLE 20.0 18.2 20.4 22.7 23.6 24.3 24.8 25.3 27.0 28.5 KISHWUAUKEE RIVER BELVIDERE 9.0 7.5 8.0 8.3 8.8 9.1 9.6 9.9 10.0 10.5 PERRYVILLE 12.0 11.5 12.1 12.3 12.7 13.2 13.6 14.2 14.7 15.8 SOUTH BRANCH KISHWAUKEE RIVER DE KALB 10.0 5.7 6.0 6.5 6.7 7.3 7.7 8.3 8.7 9.3 ROCK RIVER ROCKTON 10.0 12.5 13.0 13.6 13.9 14.3 15.1 15.3 15.9 16.6 LATHAM PARK 10.0 11.4 11.6 11.8 12.0 12.1 12.7 12.9 13.3 14.6 ROCKFORD 9.0 10.6 11.2 11.6 12.1 12.5 13.3 13.6 14.0 14.7 BYRON 13.0 13.2 13.5 14.1 14.5 15.2 16.1 16.3 17.0 17.8 PECATONICA RIVER SHIRLAND 12.0 14.6 15.0 15.4 15.6 16.0 16.3 17.0 17.5 18.4
THIS LONG-RANGE PROBABILISTIC OUTLOOK CONTAINS 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...AND 30 TO 90 DAY LONG-RANGE OUTLOOKS OF TEMPERATURE AND PRECIPITATION. BY PROVIDING THE COMPLETE RANGE OF PROBABILISTIC NUMBERS...THE LEVEL OF RISK ASSOCIATED WITH LONG-RANGE PLANNING DECISIONS CAN BE DETERMINED. THESE PROBABILISTIC FORECASTS ARE PART OF THE NATIONAL WEATHER SERVICE ADVANCED HYDROLOGIC PREDICTION SERVICE.
...FLOOD TERMINOLOGY... THE TERM MINOR FLOODING IS USED TO INDICATE MINIMAL OR NO PROPERTY DAMAGE. HOWEVER SOME PUBLIC INCONVENIENCE IS POSSIBLE.
MODERATE FLOODING IS USED TO INDICATE THE INUNDATION OF SECONDARY ROADS. TRANSFER TO A HIGHER ELEVATION MAY BE NECESSARY TO SAVE PROPERTY. SOME EVACUATIONS MAY BE REQUIRED.
MAJOR FLOODING IS USED TO INDICATE EXTENSIVE INUNDATION AND PROPERTY DAMAGE USUALLY CHARACTERIZED BY EVACUATION OF PEOPLE AND LIVESTOCK AND CLOSURE OF BOTH PRIMARY AND SECONDARY ROADS. VISIT OUR WEB PAGE AT WEATHER.GOV/CHICAGO FOR MORE WEATHER AND RIVER INFORMATION INCLUDING GRAPHS OF PROBABILISTIC RIVER OUTLOOKS. THE NEXT SPRING FLOOD OUTLOOK WILL BE ISSUED ON FRIDAY MARCH 28 2008. $$ MORRIS
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