Flash Flooding and Flooding in Minnesota, September 20 to 23, 2016

Name: Flash Flooding and Flooding in Minnesota, September 20 to 23, 2016
Start: 2016-09-20T21:28
End: 2016-09-23T18:00
Location: Minnesota

September 20 to 23, 2016 · NWS MPX · 58 events in 14 counties and zones

On the evening of September 20th, a warm front was stretched west to east across southern Minnesota originating from a developing low pressure system across the South Dakota and Nebraska border. The weather pattern, and associated boundaries were nearly stationary through early Thursday morning, September 22nd.

Where it happened

Every event with a place to put it. Tap one for its entry below.

Tornadoes
Tropical storms and surge
Floods
Wind
Hail
Winter weather
Heat and drought
Cold
Fire, smoke and dust
Marine and coastal
Other

Open the live radar over this ground

The toll

Deaths: 0
Injuries: 0
Property damage: $2.0 million
Crop damage: None recorded
Events: 58

Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.

What happened

The episode as NWS MPX wrote it up.

Although the most significant part of this weather event was flooding, some large hail was observed the evening of September 20th, and during the afternoon and evening of Wednesday, September 21st.

The evening of Tuesday, September 20th, an area of thunderstorms formed along and north of the warm front in southern Minnesota. Heavy rain fell in south central Minnesota, especially near Waseca. A Flash Flood Warning was issued for portions of southern Minnesota but no major issues were reported. Ultimately, 2 to 3 inches of rain fell in a rather short period of time near Janesville and Waseca late Tuesday night. This rainfall event, although localized, created very wet antecedent conditions before the main heavy rainfall event developed the evening of Wednesday, September 21st.

The evening and overnight of September 21st-22nd saw much more and widespread heavy rainfall across southern Minnesota. Two areas that were hit the hardest occurred across Hennepin and Anoka counties, in the Twin Cities metro area, and around Mankato, Waseca and Owatonna.

The worst and most significant flash flood event occurred between Greenfield, Corcoran in Hennepin County, eastward to Spring Lake Park, Fridley, Lexington and Lino Lakes in Anoka County. The first heavy rainfall event occurred between 5 PM and 8 PM CST. This event produced between 3 and 6 inches of rainfall in less than 3 hours, with some areas receiving 3 to 4 inches of rain in less than 90 minutes based on local observations. The second event produced an additional 2 to 4 inches after 9 PM CST in the same areas which prompted a small region to have a Flash Flood Emergency issued. Upwards of 7, to nearly 10 inches of rain fell before midnight. Due to this extreme event, there were hundreds of abandoned cars with water reaching the car windows in northwest metro suburbs during the height of the storm. Interstate 94 in the north metro was closed for a period that night. Five private residents had 3-4 feet of water in their basements, and two homes had water completed filled to the top in Maple Grove. In addition to the homes, there were 15 county roads closed at one point around Maple Grove and Brooklyn Park based on reports from the Hennepin County Emergency Management. A small part of Highway 169 near the border of Maple Grove and Brooklyn Park was closed for 4 days due to the runoff from earlier torrential rainfall.

The other flash flood event occurred near Mankato (northeast Blue Earth County) eastward through Waseca and Steele Counties. Thunderstorms that developed Wednesday evening were much more widespread, and trained over the same areas along and north of the front. Rainfall amounts ranged from 4 to 6 inches from Mankato, to Albert Lea, Kenyon and Faribault. The highest 24-hour total ending on the morning of September 22 was 7.64 inches at the U of M Southern Research and Outreach Center in Waseca. This brought the two-day total at that location to 10.16 inches, including the 2.52 inches of rain that fell with the first wave on September 20-21. This is the highest two-day total ever recorded in Waseca.

Due to the ground that was already saturated from earlier torrential rainfall the day before, the flooding situation became extreme, with ongoing areal flooding lasting for the next several days as the runoff continued.

There were many reports of basements flooded, closed roads and washouts, and standing water in Waseca and other locations as well. There were a few homes in Waseca that were evacuated due to the flood waters. The indoor ice arena in Waseca had six inches of water on the freshly-iced rink. Loon Lake in Waseca rose over its banks and flooded nearby streets in town. The rising waters of Fountain Lake in Albert Lea encroached into town during the day on September 23, detouring Highway 65 (Main Street) near the lake.

According to the emergency manager at least 75 percent of the homes in the Waseca area were damaged by flooding. A line nearly 200 yards long of trucks and cars filled with wet carpets, furniture and waterlogged TVs and appliances was lined up at the City of Waseca debris dump site.

There was major flooding on rivers and creeks across portions of southern Minnesota that lasted for several days beyond the event. The North Fork Zumbro River near Wanamingo reached a record flood stage of 23.38 feet during the morning of 9/22. The previous record was 23.2 feet. Other rivers, and streams that rose significant or crested above flood stage were the Straight, Cannon, Cobb and Le Sueur.

During the height of the flood event, I-694, I-90, and Highway 169 in Minnesota were closed for a time due to high water. Dozens of county roads were also closed near Waseca, Minnesota in south central MN. Many stalled vehicles, flooded basements and a few localized evacuations took place around southern Minnesota.

Reports from the Minnesota Department of Transportation had numerous state roads closed through Thursday, September 22nd as runoff continued. Some of the major roads that were affected by the flood waters in south central Minnesota included; Highways 13, 14, 30, 71, 83, 22, 28, and 15.

Several of the main roads didn't reopen until Friday morning, September 23rd. Plus, a few didn't open until the following week.

In addition to the road closures, several gravel roads experienced erosion. Within the Blue Earth County Park System, Wildwood Park and the Fort Le Hillier Canoe Landing had been closed.

Several daily rainfall records were broken which included; Waseca at 7.64 inches, 5.15 inches at Wells, 3.70 inches at Zumbrota, and 3.09 inches at Winnebago.

Due to the extreme event, the President of the United States officially declared the significant storm and flooding in September a major disaster. This declaration brought federal and state aid to the following counties: Blue Earth, Freeborn, Goodhue, Le Sueur, Rice, Steele, Waseca, and others in southeast Minnesota.

The widespread flooding caused significant damage to roads, buildings, and infrastructure. According to a preliminary damage report completed in October 2016, officials determined $8.3 million in public infrastructure damage and $10.1 million in estimated individual needs were noted. Over 6,000 homes and businesses were affected by the flood waters across southern Minnesota.

What forecasters said that day

The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Twin Cities, MN wrote its last area forecast discussion before the first event at Sep 20, 5:36 PM CST, 3 hours 52 minutes earlier.

Area forecast discussion, Sep 20, 5:36 PM CST, 3 hours 52 minutes before

Area Forecast Discussion
National Weather Service Twin Cities/Chanhassen MN
636 PM CDT TUE SEP 20 2016

.SHORT TERM...(This evening through Wednesday)
Issued at 330 PM CDT Tue Sep 20 2016

The short term forecast revolved around convection both tonight
along the MN/WI border, and also Wednesday and Wednesday night.
Flooding is the main concern. Considering the forecast analogs which
continue to show Sept 22 2010 as a top match, there is potential for
high end significant flooding, which is discussed further in the
Hydrology section of the AFD.

From a meteorology perspective, folks in north central IA are
enjoying a warm fall day with temperatures in the mid 80s and
dewpoints in the 40s, which does not exactly support heavy rain and
flooding. However just to the west low to mid 70 dewpoints are in
place along the Missouri River, and this plume of low level moisture
will be a key ingredient for heavy rain. Another key is the frontal
boundary that will stall out across the region, and allow for
repeated rounds of convection. Lastly, the tropopause height on the
Bufkit soundings exceed 150 mb by Wednesday night indicating a
tropical airmass and potential to over-achieve in terms of heavy
rain and flooding.

Those are the ingredients, and it appears that convection will
develop after sunset along the aforementioned frontal boundary. This
will gradually slide southeast along the MN/WI border, but could
produce heavy rain as it does. There is a secondary risk for severe
wind and hail highlighted by the SPC slight risk area. There should
be a break on Wednesday morning according to the HiRes models, but
with the warm front in place did not go completely dry. Increased
pops again Wednesday late afternoon as storms should begin to fire
in concert with a destabilizing atmosphere south of the front.

.LONG TERM...(Wednesday night through Tuesday)
Issued at 330 PM CDT Tue Sep 20 2016

The heavy rainfall and flooding remain the primary weather threats
into Thursday. Depending on overall convective trends during the day
Wednesday...Wednesday night into Thursday still looks to be the
greatest risk periods for excessive rainfall.

We issued the flash flood watch earlier with confidence high enough
to include portions of the cwa through Thursday.

The nearly stationary frontal boundary is forecast to remain across
southern MN and will remain the focus for convection and heavy rain.
PW's continue to increase into Wednesday night pushing the 2 inch
value across the southeast cwa as a weak surface low lifts northeast
along the frontal boundary. This should focus the heavy rain
potential along and south of this boundary. Forcing from the strong
300hpa polar jet across southern Canada and increased moisture
convergence into system will generate 1 to 3 inch QPF amounts across
the watch area during this period. Totals are pushing 2 to 4 inches
for an average coverage for the region. We certainly have the
potential of locally high amounts...with the 12z CIPS analog once
again pointing to the Sept 2010 event.

As the northern stream trough finally exits to the east into
Thursday...the frontal boundary is expected to sag south over Iowa
...and should decrease the coverage area of any significant
accumulation. The models suggest the western CONUS trough will
advance east into Friday and this will lift the front back north as
a warm front. Later Friday into Saturday. This will increase the
convective chances once again. As the trough travels east into the
weekend...the models diverge on handling the possibility of
developing a cut off circulation. The GFS has been fairly consistent
with a more progressive trough/polar jet across the northern
CONUS...so will continue to move pops east through Sunday night.
Will hold onto some small chance pops to the east for the remainder
of the long term...in case the trough slows more toward the ECMWF
solution...and collaboration purposes.

&&

.AVIATION...(For the 00Z TAFS through 00Z Wednesday evening)
Issued at 636 PM CDT Tue Sep 20 2016

SHRA/TSRA will develop this evening across southern MN and
progress slowly ESE during the night. Current thinking is that
much of the activity will be to the east of KRWF and south of KMSP
and KEAU. As the night progresses, low level moisture will be on
the increase with MVFR ceilings/visibilities likely by daybreak
for all sites but KSTC and KAXN. The low ceilings will prevail
through the day as a nearly stationary front meanders across
southern MN and WI. Another round of TSRA is likely Wednesday
afternoon and evening. This time the storms will likely be farther
north and more across the Twin Cities and point east.

KMSP...Elevated instability is evident this evening across the
local area with rather extensive ACCAS. A very tight and strong
gradient in instability exists currently along the MN/IA border.
Storms will develop along this gradient this evening and reach up
to near the Twin Cities by 06z and persist through the overnight
hours. Used VCTS with tempo SHRA with confidence higher on
thunderstorms over southern MN. Kept the forecast of low ceilings
and visibilities for late in the night and through the day on
Wednesday due to a frontal boundary to our south. ENE winds 10
knots or less through the period.

/OUTLOOK FOR KMSP/
Thu...MVFR. IFR likely with SHRA/TS. Wind SE 10-20 kts.
Fri...MVFR possible. Wind E 5-15kts.
Sat...VFR with MVFR/SHRA possible. Wind SE at 10g15kt.

&&

.HYDROLOGY...
Issued at 330 PM CDT Tue Sep 20 2016

In addition to the flash flood potential, river flooding is a threat
heading into the weekend. Soils remain very saturated, crops are
done taking in water, and river levels are at substantially higher
levels than normal for September (in fact, well above what we were
seeing in June and July). Running the models with current 48 hour
QPF (1.5 to 3 inches) shows a number of rivers in south
central/eastern MN and western WI rise quickly to near flood stage;
however, only an additional inch or two of mean areal precipitation
in any one basin would cause major rises to well above flood stages.
We'll be closely watching the Cannon, Zumbro, Blue Earth, Straight,
and lower Chippewa (WI) Rivers along with all tributaries to see how
the precipitation develops.

&&

.MPX Watches/Warnings/Advisories...
WI...Flash Flood Watch from 10 PM CDT this evening through Thursday
     evening for WIZ024-026-028.

     Flash Flood Watch from Wednesday afternoon through Thursday
     morning for WIZ014>016-023-025-027.

MN...Flash Flood Watch from 10 PM CDT this evening through Thursday
     evening for MNZ067-069-070-074>078-082>085-091>093.

     Flash Flood Watch from Wednesday afternoon through Thursday
     morning for MNZ051>053-059>063-066-068.

&&

SHORT TERM...JRB
LONG TERM...DWE
AVIATION...RAH
HYDROLOGY...CCS

Hazardous weather outlook, Sep 20, 12:28 PM CST, 9 hours before

HAZARDOUS WEATHER OUTLOOK
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
128 PM CDT TUE SEP 20 2016

MNZ051>053-059>063-066>070-074>078-082>085-091>093-WIZ014>016-
023>028-211200-
SHERBURNE-ISANTI-CHISAGO-WRIGHT-HENNEPIN-ANOKA-RAMSEY-WASHINGTON-
MCLEOD-SIBLEY-CARVER-SCOTT-DAKOTA-BROWN-NICOLLET-LE SUEUR-RICE-
GOODHUE-WATONWAN-BLUE EARTH-WASECA-STEELE-MARTIN-FARIBAULT-
FREEBORN-POLK-BARRON-RUSK-ST. CROIX-PIERCE-DUNN-PEPIN-CHIPPEWA-
EAU CLAIRE-
128 PM CDT TUE SEP 20 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
MINNESOTA...EAST CENTRAL MINNESOTA...SOUTH CENTRAL MINNESOTA...
SOUTHEAST MINNESOTA...NORTHWEST WISCONSIN AND WEST CENTRAL
WISCONSIN.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THUNDERSTORMS WITH HEAVY RAIN ARE EXPECTED TO DEVELOP TONIGHT.
FLASH FLOODING IS THE PRIMARY THREAT...BUT LARGE HAIL AND DAMAGING
WIND IS ALSO POSSIBLE.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

A FLASH FLOOD WATCH HAS BEEN ISSUED FOR MUCH OF THE AREA FOR
TONIGHT INTO THURSDAY. SEVERAL INCHES ADDITIONAL INCHES OF RAIN
ARE POSSIBLE THROUGH THE WEEKEND WHICH COULD CAUSE FLOODING.
THERE IS POTENTIAL FOR THE FLOODING TO BE WIDESPREAD AND
SIGNIFICANT...ESPECIALLY WEDNESDAY INTO THURSDAY.

THERE IS A MARGINAL RISK FOR SEVERE WEATHER WEDNESDAY AFTERNOON
AND WEDNESDAY NIGHT. LARGE HAIL AND DAMAGING WINDS ARE POSSIBLE.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED.

MNZ041>045-047>050-054>058-064-065-073-211200-
DOUGLAS-TODD-MORRISON-MILLE LACS-KANABEC-STEVENS-POPE-STEARNS-
BENTON-LAC QUI PARLE-SWIFT-CHIPPEWA-KANDIYOHI-MEEKER-
YELLOW MEDICINE-RENVILLE-REDWOOD-
128 PM CDT TUE SEP 20 2016

THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL
MINNESOTA...EAST CENTRAL MINNESOTA...SOUTHWEST MINNESOTA AND WEST
CENTRAL MINNESOTA.

.DAY ONE...THIS AFTERNOON AND TONIGHT

THUNDERSTORMS WITH HEAVY RAIN ARE POSSIBLE TONIGHT. THE THREAT
FOR SEVERE WEATHER IS LOW.

.DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY

SEVERAL INCHES ADDITIONAL INCHES OF RAIN ARE POSSIBLE THROUGH THE
WEEKEND WHICH COULD CAUSE FLOODING. THE SEVERE WEATHER THREAT IS
LOW.

.SPOTTER INFORMATION STATEMENT...

SKYWARN SPOTTER ACTIVATION WILL NOT BE NEEDED.

In the hours before

Special weather statement, Sep 20, 6:49 PM CST, 2 hours 39 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
749 PM CDT TUE SEP 20 2016

WIZ028-210115-
EAU CLAIRE-
749 PM CDT TUE SEP 20 2016

...A STRONG THUNDERSTORM WILL AFFECT EASTERN EAU CLAIRE COUNTY...

AT 748 PM CDT...A STRONG THUNDERSTORM WAS LOCATED OVER FALL
CREEK...OR 10 MILES SOUTHEAST OF EAU CLAIRE...MOVING EAST AT 40 MPH.

HALF INCH HAIL IS POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
AUGUSTA...FALL CREEK...FAIRCHILD...LUDINGTON...LAKE EAU CLAIRE COUNTY
PARK...ALLEN AND BRACKETT.

THIS INCLUDES INTERSTATE 94 IN WISCONSIN BETWEEN MILE MARKERS 75 AND
80.

LAT...LON 4466 9137 4484 9135 4483 9092 4461 9092
      4460 9093
TIME...MOT...LOC 0048Z 270DEG 37KT 4475 9128

RAH

Special weather statement, Sep 20, 8:49 PM CST, 39 minutes before

SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE TWIN CITIES/CHANHASSEN MN
949 PM CDT TUE SEP 20 2016

MNZ075-076-083-210315-
NICOLLET-BLUE EARTH-LE SUEUR-
949 PM CDT TUE SEP 20 2016

...A STRONG THUNDERSTORM WILL AFFECT NORTHEASTERN BLUE EARTH...
SOUTHEASTERN NICOLLET AND SOUTHWESTERN LE SUEUR COUNTIES...

AT 948 PM CDT...A STRONG THUNDERSTORM WAS LOCATED OVER JUDSON...OR 7
MILES WEST OF MANKATO...MOVING EAST AT 25 MPH.

DIME SIZE HAIL IS POSSIBLE WITH THIS STORM.

LOCATIONS IMPACTED INCLUDE...
MANKATO...NORTH MANKATO...ST. PETER...EAGLE LAKE...NICOLLET...MADISON
LAKE...KASOTA...JUDSON...OSHAWA...SKYLINE AND MANKATO AIRPORT.

THIS INCLUDES THE FOLLOWING HIGHWAYS...
 U.S. HIGHWAY 14 BETWEEN MILE MARKERS 119 AND 140.
 U.S. HIGHWAY 169 BETWEEN MILE MARKERS 48 AND 68.

TORRENTIAL RAINFALL IS ALSO OCCURRING WITH THIS STORM...AND MAY CAUSE
LOCALIZED FLOODING. DO NOT DRIVE YOUR VEHICLE THROUGH FLOODED
ROADWAYS.

THIS STORM MAY INTENSIFY...SO BE CERTAIN TO MONITOR LOCAL RADIO
STATIONS AND AVAILABLE TELEVISION STATIONS FOR ADDITIONAL INFORMATION
AND POSSIBLE WARNINGS FROM THE NATIONAL WEATHER SERVICE.

LAT...LON 4413 9417 4425 9427 4436 9393 4416 9379
TIME...MOT...LOC 0248Z 259DEG 15KT 4418 9414

SPD

The radar

The Minneapolis radar (KMPX), 84 km away, was scanning. The volume nearest the first event began at 03:26 UTC.

Open the radar archive at this moment

Event by event

22 heavy rain, 19 hail, 8 flash flood, 7 flood, 2 thunderstorm wind. Local standard time, as filed.

Hail, Blue Earth

When: September 20, 9:28 PM CST
Where: Blue Earth County, 1.64 mi ESE of Mankato
Measured: 1.75 in hail
Reported by: Public
Coordinates: 44.160, -93.990

Hail, Dakota

When: September 20, 10:10 PM CST
Where: Dakota County, 2 mi WSW of Randolph
Measured: 0.75 in hail
Reported by: Trained Spotter
Coordinates: 44.519, -93.058

Hail, Dakota

When: September 20, 10:30 PM CST
Where: Dakota County, 0.69 mi N of Eagan
Measured: 0.88 in hail
Reported by: Trained Spotter
Coordinates: 44.810, -93.170

Hail, Dakota

When: September 20, 10:30 PM CST
Where: Dakota County, 2.81 mi S of Mendota
Measured: 0.88 in hail
Reported by: Trained Spotter
Coordinates: 44.840, -93.180

Hail, Dakota

When: September 20, 10:30 PM CST
Where: Dakota County, 1.03 mi N of Eagan
Measured: 1.25 in hail
Reported by: Trained Spotter
Coordinates: 44.815, -93.168

Hail, Dakota

When: September 20, 10:35 PM CST
Where: Dakota County, 1.62 mi WNW of Eagan
Measured: 0.88 in hail
Reported by: Public
Coordinates: 44.810, -93.200

Hail, Dakota

When: September 20, 10:45 PM CST
Where: Dakota County, 0.69 mi S of Inver Grove Heights
Measured: 1 in hail
Reported by: Public
Coordinates: 44.840, -93.030

Hail, Washington

When: September 20, 10:50 PM CST
Where: Washington County, Newport
Measured: 0.88 in hail
Reported by: Public
Coordinates: 44.870, -93.000

Most of the hail that fell was pea to penny size.

Hail, Washington

When: September 20, 11:00 PM CST
Where: Washington County, 2.55 mi WSW of Cottage Grove
Measured: 0.75 in hail
Reported by: Public
Coordinates: 44.820, -92.930

Hail, Washington

When: September 20, 11:05 PM CST
Where: Washington County, 2.04 mi E of St Paul Park
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 44.852, -92.948

Hail, Washington

When: September 20, 11:11 PM CST
Where: Washington County, Cottage Grove
Measured: 0.88 in hail
Reported by: Public
Coordinates: 44.830, -92.880

Hail, Goodhue

When: September 21, 1:30 AM CST
Where: Goodhue County, 0.85 mi NW of Zumbrota
Measured: 0.75 in hail
Reported by: Fire Department/Rescue
Coordinates: 44.310, -92.680

Heavy Rain, Ramsey

When: September 21, 3:00 PM CST to September 22, 5:00 AM CST
Where: Ramsey County, 2.81 mi N of Shoreview
Reported by: Trained Spotter
Coordinates: 45.120, -93.140

A local trained weather observer measured 5.22 inches of rainfall in northern Shoreview between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Hennepin

When: September 21, 3:00 PM CST to September 22, 3:00 AM CST
Where: Hennepin County, 2.13 mi NNW of Loretto
Reported by: Trained Spotter
Coordinates: 45.080, -93.660

A local trained weather observer measured 5.78 inches of rainfall north of Loretto between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Hennepin

When: September 21, 3:00 PM CST to September 22, 3:00 AM CST
Where: Hennepin County, 0.49 mi W of Crystal
Reported by: Trained Spotter
Coordinates: 45.070, -93.390

A local trained weather observer measured 5.88 inches of rainfall in southwestern Brooklyn Park, just west of Crystal. This was between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Hennepin

When: September 21, 3:00 PM CST to September 22, 3:00 AM CST
Where: Hennepin County, 1.46 mi E of Crystal Arpt
Reported by: Mesonet
Coordinates: 45.070, -93.320

A local mesonet station measured 6.15 inches of rainfall in northern Brooklyn Center between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Hennepin

When: September 21, 3:00 PM CST to September 22, 3:00 AM CST
Where: Hennepin County, 1.47 mi NNE of Hamel
Reported by: CoCoRaHS
Coordinates: 45.070, -93.520

A local trained weather observer measured 6.21 inches of rainfall near Hamel between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Hennepin

When: September 21, 3:00 PM CST to September 22, 3:00 AM CST
Where: Hennepin County, 2.76 mi N of Plymouth
Reported by: Trained Spotter
Coordinates: 45.070, -93.470

A local trained weather observer measured 6.27 inches of rainfall in southern Maple Grove between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Hennepin

When: September 21, 3:00 PM CST to September 22, 3:00 AM CST
Where: Hennepin County, 1.69 mi SE of Maple Grove
Reported by: CoCoRaHS
Coordinates: 45.130, -93.460

A local trained weather observer measured 6.44 inches of rainfall in northern Maple Grove between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Hennepin

When: September 21, 3:00 PM CST to 8:30 PM CST
Where: Hennepin County, 2.85 mi SW of Osseo
Reported by: Trained Spotter
Coordinates: 45.090, -93.460

A local trained weather observer measured 7.15 inches of rainfall in Maple Grove, just west of the intersection of Interstates 94, 494, and 694. This was during the afternoon and evening of Wednesday, September 21st.

Heavy Rain, Anoka

When: September 21, 3:00 PM CST to September 22, 6:00 AM CST
Where: Anoka County, 0.69 mi S of Lexington
Reported by: Trained Spotter
Coordinates: 45.120, -93.250

A retired NWS employee measured 7.17 inches of rainfall in Spring Lake Park between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Hennepin

When: September 21, 3:00 PM CST to September 22, 6:00 AM CST
Where: Hennepin County, 2.07 mi ESE of Osseo
Reported by: Trained Spotter
Coordinates: 45.110, -93.380

A local trained weather observer measured 7.20 inches of rainfall in Brooklyn Park (just east of Osseo) between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Anoka

When: September 21, 3:00 PM CST to September 22, 6:00 AM CST
Where: Anoka County, 1.19 mi SW of Lexington
Reported by: Trained Spotter
Coordinates: 45.120, -93.270

A local trained weather observer measured 7.65 inches of rainfall in far northern Fridley between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Hennepin

When: September 21, 3:00 PM CST to September 22, 6:00 AM CST
Where: Hennepin County, 3.2 mi SW of Osseo
Reported by: CoCoRaHS
Coordinates: 45.090, -93.470

A local trained weather observer measured 8.11 inches of rainfall in Maple Grove (on the western edge of Fish Lake) between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Hennepin

When: September 21, 3:00 PM CST to September 22, 6:00 AM CST
Where: Hennepin County, 2.53 mi ESE of Corcoran
Reported by: CoCoRaHS
Coordinates: 45.090, -93.520

A local trained weather observer measured 9.05 inches of rainfall in southwestern Maple Grove between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Hennepin

When: September 21, 3:00 PM CST to September 22, 6:00 AM CST
Where: Hennepin County, 3.2 mi SW of Osseo
Reported by: Mesonet
Coordinates: 45.090, -93.470

A local trained weather observer measured 9.76 inches of rainfall in Maple Grove (just west of Fish Lake) between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Hennepin

When: September 21, 3:00 PM CST to 11:00 PM CST
Where: Hennepin County, 2.81 mi S of Maple Grove
Reported by: Trained Spotter
Coordinates: 45.110, -93.490

A local trained weather observer measured 9.86 inches of rainfall in Maple Grove (just east of Weaver Lake) during the afternoon and evening of Wednesday, September 21st.

Hail, Ramsey

When: September 21, 3:23 PM CST
Where: Ramsey County, 1.38 mi N of Arden Hills
Measured: 0.88 in hail
Reported by: Public
Coordinates: 45.070, -93.170

Hail, Ramsey

When: September 21, 3:25 PM CST
Where: Ramsey County, 0.49 mi W of Shoreview
Measured: 1 in hail
Reported by: Broadcast Media
Coordinates: 45.080, -93.140

Hail, Ramsey

When: September 21, 3:30 PM CST
Where: Ramsey County, 1.2 mi NE of North Oaks
Measured: 1 in hail
Reported by: Public
Coordinates: 45.090, -93.080

Hail, Wright

When: September 21, 5:25 PM CST
Where: Wright County, 1.19 mi NW of Buffalo Muni Arpt
Measured: 0.75 in hail
Reported by: Amateur Radio
Coordinates: 45.180, -93.870

Hail, Hennepin

When: September 21, 5:28 PM CST
Where: Hennepin County, 2.07 mi ENE of Rockford
Measured: 0.88 in hail
Reported by: Amateur Radio
Coordinates: 45.100, -93.700

Heavy Rain, Faribault

When: September 21, 6:00 PM CST to September 22, 8:00 AM CST
Where: Faribault County, 3.5 mi W of Frost
Reported by: Trained Spotter
Coordinates: 43.580, -94.000

A local trained weather observer measured 5.10 inches of rainfall near Frost between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Faribault

When: September 21, 6:00 PM CST to September 22, 6:00 AM CST
Where: Faribault County, 0.5 mi W of Wells
Reported by: COOP Observer
Coordinates: 43.750, -93.740

A local trained weather observer measured 5.15 inches of rainfall near Wells between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Goodhue

When: September 21, 6:00 PM CST to September 22, 5:00 AM CST
Where: Goodhue County, 0.49 mi W of Kenyon
Reported by: CoCoRaHS
Coordinates: 44.280, -92.990

A local trained weather observer measured 5.16 inches of rainfall near Kenyon between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Steele

When: September 21, 6:00 PM CST to September 22, 5:00 AM CST
Where: Steele County, 4.94 mi SSW of Lemond
Reported by: Trained Spotter
Coordinates: 43.910, -93.400

A local trained weather observer measured 5.22 inches of rainfall south of Lemond between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Blue Earth

When: September 21, 6:00 PM CST to September 22, 6:00 AM CST
Where: Blue Earth County, 1.49 mi W of Eagle Lake
Reported by: COOP Observer
Coordinates: 44.170, -93.910

A local trained weather observer measured 5.25 inches of rainfall near Eagle Lake between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Waseca

When: September 21, 6:00 PM CST to September 22, 6:00 AM CST
Where: Waseca County, 0.85 mi NE of Waseca
Reported by: CoCoRaHS
Coordinates: 44.090, -93.490

A local trained weather observer measured 6.55 inches of rainfall near Waseca between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Heavy Rain, Waseca

When: September 21, 6:00 PM CST to September 22, 8:00 AM CST
Where: Waseca County, 1.21 mi SW of Waseca
Reported by: COOP Observer
Coordinates: 44.070, -93.520

A National Weather Service coop observer measured 7.64 inches of rainfall southwest of Waseca between Wednesday afternoon, September 21st, to the early morning of Thursday, September 22nd.

Hail, Wright

When: September 21, 6:07 PM CST
Where: Wright County, 0.98 mi W of Rockford
Measured: 1 in hail
Reported by: Trained Spotter
Coordinates: 45.090, -93.760

Hail, Wright

When: September 21, 6:19 PM CST
Where: Wright County, Rockford
Measured: 1 in hail
Reported by: Amateur Radio
Coordinates: 45.090, -93.740

Flash Flood, Anoka

When: September 21, 6:45 PM CST to 9:45 PM CST
Where: Anoka County, 1.19 mi NW of Lexington to 0.92 mi W of Lexington
Cause: Heavy Rain
Reported by: Law Enforcement
Coordinates: 45.140, -93.270

One foot of flowing water closed University Avenue and County Road 47 near North Town Mall.

Flash Flood, Hennepin

When: September 21, 7:45 PM CST to 10:45 PM CST
Where: Hennepin County, 0.85 mi NW of Brooklyn Park to 0.85 mi WSW of Brooklyn Park
Cause: Heavy Rain
Reported by: Trained Spotter
Coordinates: 45.130, -93.340

Flood waters caused parts of Noble Parkway to close along Shingle Creek. Several cars were stalled along Noble Parkway.

Thunderstorm Wind, Hennepin

When: September 21, 8:00 PM CST
Where: Hennepin County, 1.38 mi S of Edina
Measured: 56 kt (64 mph) estimated gust
Reported by: Trained Spotter
Coordinates: 44.880, -93.350

A large tree, 28 inches in diameter, was blown down at Highway 100 and 70th, in Edina.

Flash Flood, Hennepin

When: September 21, 8:45 PM CST to 10:45 PM CST
Where: Hennepin County, 2.07 mi ESE of Osseo to 1.32 mi NE of Hamel
Cause: Heavy Rain
Reported by: Emergency Manager
Coordinates: 45.110, -93.380

Local law enforcement officials closed numerous roads in northern Hennepin county due to flooded roadways. Officials indicated that numerous vehicles stalled and became submerged in the flood waters, especially in the cities of Maple Grove and Brooklyn Park where locally 7 to 10 inches of rain fell in less than 6 hours.

Flash Flood, Waseca

When: September 21, 9:00 PM CST to September 22, 2:30 AM CST
Where: Waseca County, 1 mi W of Waseca to 1.55 mi NNW of Waseca
Cause: Heavy Rain
Reported by: Trained Spotter
Coordinates: 44.078, -93.520

Several roads in Waseca had one to two feet of flowing water. In addition, an unverified report of 10 inches of rain fell in the northeast part of Waseca late Wednesday night. Several homes and businesses in Waseca had flooded basements and other structural problems due to the flood waters.

Flash Flood, Anoka

When: September 21, 9:15 PM CST to September 22, 12:15 AM CST
Where: Anoka County, 0.87 mi NW of Lexington to 0.68 mi WNW of Lexington
Cause: Heavy Rain
Property damage: $1.0 million
Reported by: Trained Spotter
Coordinates: 45.141, -93.260

Flood waters caused numerous roads to become impassable on either side of University Avenue, between Highway 610 at Coon Rapids Blvd, and I-694. Water was several feet deep in far northern Fridley, with significant damage at the SpringBrook apartments, where flood waters entered seven of the nine buildings and adjacent garages, resulting in damage to many dozens of apartments. Other homes and buildings in the area also had flood waters inside their structures.

Thunderstorm Wind, Freeborn

When: September 21, 10:14 PM CST
Where: Freeborn County, (Ael)albert Lea Arpt
Measured: 58 kt (67 mph) measured gust
Reported by: AWOS
Coordinates: 43.680, -93.370

Flash Flood, Waseca

When: September 21, 11:30 PM CST to September 22, 2:30 AM CST
Where: Waseca County, 1.38 mi S of Waseca to 1.28 mi S of Waseca
Cause: Heavy Rain
Reported by: Law Enforcement
Coordinates: 44.060, -93.500

Highway 13 near Highway 14 was closed due to flood waters.

Flash Flood, Waseca

When: September 22, 2:30 AM CST to 4:30 AM CST
Where: Waseca County, Waseca to 0.73 mi W of Waseca
Cause: Heavy Rain
Reported by: Law Enforcement
Coordinates: 44.080, -93.500

The city of Waseca continued to receive torrential rainfall that caused several roads to close. The flood waters started to affect homes that had to be evacuated.

Flash Flood, Waseca

When: September 22, 4:30 AM CST to 6:00 AM CST
Where: Waseca County, 1.47 mi SSW of Waseca to 1.3 mi SW of Waseca
Cause: Heavy Rain
Reported by: Public
Coordinates: 44.060, -93.510

Flood waters continued to affect the city of Waseca with the community arena reported of 6-8 inches of standing water on their ice rink.

Flood, Blue Earth

When: September 22, 6:00 AM CST to September 23, 6:00 PM CST
Where: Blue Earth County, 3.05 mi ENE of Minnesota Lake to 2.35 mi NNE of Madison Lake
Cause: Heavy Rain
Reported by: County Official
Coordinates: 43.872, -93.797

Runoff from torrential rainfall that occurred across most of eastern and southern Blue Earth County Wednesday night, September 21st, caused numerous roads to remain impassable and closed.

Flood, Freeborn

When: September 22, 6:00 AM CST to September 23, 6:00 PM CST
Where: Freeborn County, 3.88 mi NNW of Freeborn to 2.82 mi WNW of Conger
Cause: Heavy Rain
Property damage: $280,000
Reported by: County Official
Coordinates: 43.817, -93.613

Runoff from torrential rainfall that occurred across most of northern Freeborn County Wednesday night, September 21st, caused numerous roads to remain impassable and closed. Local officials indicated that nearly 300 properties in Freeborn County had reported flood damage. Repair work for regrading and re-rocking gravel roads, replacing riprap and reimbursing cost were estimated at $280,000.

Flood, Steele

When: September 22, 6:00 AM CST to September 23, 6:00 PM CST
Where: Steele County, 5.75 mi N of Meriden to 5.21 mi W of Ellendale
Cause: Heavy Rain
Reported by: County Official
Coordinates: 44.163, -93.387

Runoff from torrential rainfall that occurred across most of Steele County Wednesday night, September 21st, caused numerous roads to remain impassable and closed.

Flood, Waseca

When: September 22, 6:00 AM CST to September 23, 6:00 PM CST
Where: Waseca County, 5.55 mi SE of New Richland to 3.86 mi NNE of Waseca
Cause: Heavy Rain
Reported by: County Official
Coordinates: 43.850, -93.412

Runoff from torrential rainfall that occurred across most of Waseca County Wednesday night, September 21st, caused numerous roads to remain impassable and closed.

Flood, Goodhue

When: September 22, 6:00 AM CST to September 23, 6:00 PM CST
Where: Goodhue County, 5.37 mi SSW of Kenyon to 4.51 mi ESE of Pine Is
Cause: Heavy Rain
Reported by: County Official
Coordinates: 44.204, -93.005

Runoff from torrential rainfall that occurred across most of southern Goodhue County Wednesday night, September 21st, caused numerous roads to remain impassable and closed.

Flood, Rice

When: September 22, 6:00 AM CST to September 23, 6:00 PM CST
Where: Rice County, 4.24 mi WSW of Morristown to 2.45 mi ENE of Moland
Cause: Heavy Rain
Property damage: $700,000
Reported by: County Official
Coordinates: 44.201, -93.525

Runoff from torrential rainfall that occurred across most of southern Rice County Wednesday night, September 21st, caused numerous roads to remain impassable and closed. The flooding incident created over $700,000 in property damage amounts, according to Rice County Emergency Management.

Flood, Le Sueur

When: September 22, 6:00 AM CST to September 23, 6:00 PM CST
Where: Le Sueur County, 3.85 mi SSW of Kasota to 3.33 mi W of Elysian
Cause: Heavy Rain
Reported by: County Official
Coordinates: 44.247, -93.995

Runoff from torrential rainfall that occurred across most of southern Le Sueur County Wednesday night, September 21st, caused numerous roads to remain impassable and closed.

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
Heavy Rain: Rainfall totals unusual for the place and season that did not produce a flood.
Flash Flood: Flooding that begins within six hours of the rain that causes it, or of a dam or levee failure or ice jam release, often with deadly speed.
Thunderstorm Wind: Winds from a thunderstorm of 50 knots (58 mph) or more, or lower winds that caused damage or casualties. Measured gusts are marked MG, estimated EG.
Flood: Flooding that develops more slowly than a flash flood: rivers leaving their banks, or water standing over land for an extended time.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Minnesota in 2016 Every state in 2016 This day in weather history Warnings in Minnesota, September 2016

Sources

NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 657119, 659583, 657120, 657121, 659582, 657122, 657123, 659588, 656490, 659585, 659586, 656491, 659448, 659452, 659454, 659455, 659456, 659457, 659460, 659463, 659464, 659465, 659467, 659468, 659469, 659470, 659471, 656492, 656493, 656494, 656495, 656496, 659445, 659446, 659447, 659449, 659450, 659461, 659466, 656497, and more.