Courtesy: MNDNR State Climatology Office
Heavy rains cause flooding in east central Minnesota.
For the past four days, a stationary frontal boundary has bisected Minnesota into halves, with cooler and drier air to the north -- warmer and record-breaking muggy air to the south. This created a focal point for the formation of thunderstorms. Upper-level winds paralleled the frontal boundary, directing the thunderstorms over the same landscape over and over again.
Heavy thunderstorms began just before daybreak on October 4 and continued to develop off and on for the next 30-plus hours. A large portion of central and southern Minnesota received over two inches of rain. To put this in perspective, the normal MONTHLY October rainfall in these areas is around two inches.
Central and east central Minnesota received the most rain. Numerous reports of over four inches were reported in this area. Totals exceeding six inches were reported in portions of the following counties: Dakota, Benton, Mille Lacs, Isanti, Chisago, Kanabec, Pine and Washington A six inch rainfall total in 24 hours is considered to be a 1% probability event for a given location in a given year.
A six inch daily rainfall total in October is nearly without precedent, occurring only one other time in the historical record. The 6.61 rainfall report from Wild River State Park (Chisago county) is now the largest single-day October value reported by a National Weather Service Cooperative Observer.
Numerous non-National Weather Service observing location reported rainfall totals topping seven inches. The heaviest rainfall fell upon northern Chisago and southern Pine counties. The heavy band extended into northwestern Wisconsin. The highest total reported by a non-National Weather Service observer was 8.98 inches in Rush City. An automated rain gauge at the Rush City Airport recorded 9.59 inches. Heavy rains over six inches also fell in parts of Washington County as well with a total of 6.46 inches in north central Woodbury and 7.40 inches in southwest Woodbury.
There were sporadic reports of flooding from areas where the pockets of heavy rain were the most intense. Major road closures were common: including southbound I-35E at Highway 70 in Pine County and westbound I-494 at the Wakota Bridge in Newport. Water lapped at the doorstep of at least one home in Rush City while other homes had flooded basements. About a dozen homes were affected by a pond that overflowed in Inver Grove Heights. The lift stations in Hinckley were flooded.
It is interesting to note that a smaller event effected portions of the same area last year on October 28, 2004.
This episode will undoubtedly go down in the record books as one of the most significant October rain events on record, both in terms of spatial extent and intensity.
As always, the State Climatology Office thanks the Soil and Water Conservation Districts, the National Weather Service, and all of the diligent volunteer precipitation observers who make analyses of these events possible.
Listed below are National Weather Service Statements about the heavy rain and the subsequent impacts.
PUBLIC INFORMATION STATEMENT NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN 255 PM CDT WED OCT 5 2005 ...RAINFALL TOTALS FROM TUESDAY MORNING THROUGH WEDNESDAY MORNING... THE FOLLOWING RAINFALL REPORTS ARE THE TOTALS FROM OUR DEDICATED COOPERATIVE OBSERVERS...TRAINED SPOTTERS...AND AUTOMATED WEATHER EQUIPMENT. LOCATION COUNTY RAINFALL TOTAL IN INCHES ...IN MINNESOTA... SPENCER BROOK ISANTI 9.00 6 W OF CAMBRIDGE ISANTI 8.70 4 W OF CAMBRIDGE ISANTI 7.80 MORRILL MORRISON 7.00 BURNSVILLE DAKOTA 6.76 WILD RIVER ST PK CHISAGO 6.61 ST FRANCIS ANOKA 6.24 MINNETONKA HENNEPIN 6.20 W OF CAMBRIDGE ISANTI 6.00 MORA KANABEC 5.78 INVER GROVE HTS DAKOTA 5.67 RICE BENTON 5.57 WOODBURY WASHINGTON 5.55 SW MINNEAPOLIS HENNEPIN 5.27 CAMBRIDGE ISANTI 5.20 STILLWATER WASHINGTON 5.04 BECKER SHERBURNE 4.89 ST JOSEPH STEARNS 4.70 MPLS/ST PAUL APT HENNEPIN 4.62 SAVAGE SCOTT 4.55 FRIDLEY ANOKA 4.55 CARLOS AVERY ANOKA 4.51 CLEAR LAKE SHERBURNE 4.50 CHANHASSEN 2SW CARVER 4.48 CHANHASSEN NWS CARVER 4.40 SPRING PARK HENNEPIN 4.30 GOLDEN VALLEY HENNEPIN 4.27 S MINNEAPOLIS HENNEPIN 4.25 MPLS LOCK/DAM HENNEPIN 4.24 MAPLEWOOD RAMSEY 4.18 NEW HOPE HENNEPIN 4.18 SHERBURNE SHERBURNE 4.18 CHASKA CARVER 4.14 PRIOR LAKE SCOTT 4.10 ONAMIA MILLE LACS 4.10 ST CLOUD APT SHERBURNE 4.07 ST PAUL APT DAKOTA 4.01 WACONIA CARVER 4.00 EDEN PRAIRIE APT HENNEPIN 3.95 ST CLOUD STATE STEARNS 3.79 LITTLE FALLS MORRISON 3.78 MILACA MILLE LACS 3.58 NORTH ST PAUL RAMSEY 3.56 FOREST LAKE CHISAGO 3.52 PLYMOUTH HENNEPIN 3.50 HIGHLAND PARK RAMSEY 3.45 LONG PRAIRIE TODD 2.98 GRANITE FALLS YELLOW MED 2.97 WATERTOWN CARVER 2.84 CARLOS DOUGLAS 2.64 ALEXANDRIA DOUGLAS 2.58 REDWOOD FALLS REDWOOD 2.57 MORRIS STEVENS 2.43 DASSEL MEEKER 2.35 REDWOOD FALLS REDWOOD 2.24 ROCKFORD WRIGHT 2.06 LITCHFIELD MEEKER 1.81 FARMINGTON DAKOTA 1.80 HASTINGS DAKOTA 1.60 MANKATO BLUE EARTH 1.43 6S GRANITE FALLS YELLOW MED 1.42 MADISON LAC QUI PARLE 1.28 AUGUSTA CARVER 1.18 SPRINGFIELD BROWN 1.11 VESTA REDWOOD 1.11 MORGAN REDWOOD 1.10 MONTGOMERY LE SUEUR 1.10 ...IN WISCONSIN... MIKANA BARRON 9.80 BIG FALLS HYDRO RUSK 8.55 LADYSMITH APT RUSK 6.29 CUMBERLAND BARRON 5.75 2S LADYSMITH RUSK 5.47 RIDGELAND BARRON 3.61 AMERY POLK 2.65 BALDWIN ST CROIX 1.88 SPRING VALLEY PIERCE 1.50 BLOOMER CHIPPEWA 0.84 MENOMONIE DUNN 0.60 EAU CLAIRE EAU CLAIRE 0.45
PRELIMINARY LOCAL STORM REPORT NATIONAL WEATHER SERVICE DULUTH MN 1020 AM CDT WED OCT 05 2005 ..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON... ..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE.... ..REMARKS.. 0220 AM FLOOD DULUTH 46.78N 92.12W 10/03/2005 SOUTHEAST ST. LOUI MN NWS EMPLOYEE MILLER CREEK IS OUT OF ITS BANKS AND WATER IS 2 INCHES OVER SWAN LAKE ROAD 1115 AM FLOOD 3 W ASHLAND 46.58N 90.94W 10/04/2005 BAYFIELD WI PUBLIC WATER ONE FOOT OVER ROADS AT COUNTY G AND HWY 2 NEAR THE GREAT LAKES VISITOR CENTER. WATER IS ALSO BACKING INTO THE VISITOR CENTER PARKING LOT. 0845 AM FLOOD MOQUAH 46.57N 91.08W 10/04/2005 BAYFIELD WI LAW ENFORCEMENT SEVERAL ROADS BARRICADED AROUND AREA DUE TO FLOODING 0250 AM FLOOD ROCK CREEK 45.76N 92.97W 10/05/2005 PINE MN LAW ENFORCEMENT SOUTH BOUND LANE OF I-35 CLOSED FROM ROCK CREEK IN PINE COUNTY TO HARRIS IN CHISAGO COUNTY. A FEW OTHER ROADS IN PINE COUNTY ARE ALSO CLOSED DUE TO FLOODING. 0253 AM FLOOD GRANTSBURG 45.78N 92.68W 10/05/2005 BURNETT WI LAW ENFORCEMENT MANY ROADS CLOSED INCLUDING SECTIONS OF HWY 48. 0257 AM FLOOD RADISSON 45.77N 91.22W 10/05/2005 SAWYER WI LAW ENFORCEMENT HWYS H AND 27/70 CLOSED NEAR RADISSON. SECTIONS OF HWY 48 CLOSED IN SOUTH PARTS OF COUNTY. 0732 AM FLOOD MOQUAH 46.57N 91.08W 10/05/2005 BAYFIELD WI LAW ENFORCEMENT COUNTY HWY G CLOSED 0732 AM FLOOD 1 W WASHBURN 46.67N 90.91W 10/05/2005 BAYFIELD WI LAW ENFORCEMENT PORTIONS OF HWY 13 DOWN TO ONE LANE NEAR CHERRYVILLE 0845 AM FLOOD HINCKLEY 46.01N 92.94W 10/05/2005 PINE MN CO-OP OBSERVER HINCKLEY LIFT STATIONS FLOODED 0745 AM FLOOD GRANTSBURG 45.78N 92.68W 10/05/2005 BURNETT WI LAW ENFORCEMENT MANY FLOODED ROADS IN GRANTSBURG AND AROUND COUNTY. SOME CULVERTS WASHED OUT 0745 AM FLOOD SPOONER 45.82N 91.89W 10/05/2005 WASHBURN WI LAW ENFORCEMENT PART OF HWY 253 WASHED OUT. LOCALIZED FLOODING ON OTHER ROADS. RISING WATERS ON LAKE HAS CAUSED A PONTOON BOAT TO FLOAT INTO A YARD. 0745 AM FLOOD RADISSON 45.77N 91.22W 10/05/2005 SAWYER WI LAW ENFORCEMENT SEVERAL ROADS FLOODED WITH UP TO A FOOT OF WATER AROUND COUNTY.