Flash Flood and Flooding in Indiana, August 23 to 25, 2007

Name: Flash Flood and Flooding in Indiana, August 23 to 25, 2007
Start: 2007-08-23T15:14
End: 2007-08-25T07:00
Location: Indiana

August 23 to 25, 2007 · NWS LOT · 17 events in 4 counties and zones

Powerful, severe storms moved across northwest Indiana during the afternoon and evening hours of August 23rd.

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: 2
Injuries: 1
Property damage: $6.5 million
Crop damage: None recorded
Events: 17

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 LOT wrote it up.

Powerful, severe storms moved across northwest Indiana during the afternoon and evening hours of August 23rd.

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 Chicago, IL wrote its last area forecast discussion before the first event at Aug 23, 1:13 PM EST, 2 hours 1 minute earlier.

Area forecast discussion, Aug 23, 1:13 PM EST, 2 hours 1 minute before

AREA FORECAST DISCUSSION...CORRECTION
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
113 PM CDT THU AUG 23 2007

POTENTIALLY ACTIVE AFTERNOON SETTING UP OVER NORTHERN ILLINOIS AND
NW INDIANA.

SHORTWAVE OVER CENTRAL/EASTERN IOWA IS PROGRESSING ENE WITH
CONVECTION...LIKELY SLIGHTLY ELEVATED...ALREADY ONGOING ALONG THE
LEADING EDGE OF THE STRONGER ASCENT ASSOCIATED WITH THIS WAVE. OVER
NORTHERN ILLINOIS CONSIDERABLE SUBSIDENCE HAS BEEN NOTED ON WATER
VAPOR IMAGERY THIS MORNING WHICH COMBINED WITH A RATHER DEEP
ISOTHERMAL LAYER/CAP NOTED ON RECENT ORD ACARS SOUNDING IS DOING A
NICE JOB OF SUPPRESSING THE CU FIELD.

COMBINATION OF CONTINUED STRONG HEATING ALONG WITH INCREASING ASCENT
ASSOCIATED WITH THE APPROACHING EASTERN IOWA SHORTWAVE SHOULD DO A
NICE JOB OF ERODING THE BOUNDARY LAYER BASED CONVECTIVE INHIBITION
AND ALLOWING CONVECTION OVER IOWA TO BECOME ROOTED IN THE BOUNDARY
LAYER AS IT MOVES INTO NORTHERN ILLINOIS. RECENT RADAR TRENDS HAVE
BEEN REVEALING A SLOW INCREASE IN THE INTENSITY OF THE CONVECTION
OVER IOWA AND WOULD ANTICIPATE THIS TREND TO CONTINUE FOR THE NEXT
HOUR/TWO.  MID LEVEL LAPSE RATES ARENT PARTICULARLY STEEP HOWEVER
VERY HIGH THETA-E AIRMASS WILL LIKELY OFFSET THE RATHER MODEST LAPSE
RATES AND ALLOW FOR MODERATE INSTABILITY TO DEVELOP.

WHILE MLCAPES WILL NOT BE AS IMPRESSIVE AS YESTERDAY...UNSEASONABLY
STRONG MID LEVEL FLOW ASSOCIATED WITH THE APPROACHING JET SHOULD
LEAD TO MUCH MORE ORGANIZED SEVERE THREAT THIS AFTERNOON.
WINCHESTER/BLUE RIVER PROFILERS BOTH SHOW PRESENCE OF 45-50KT WINDS
AT 5KM...WITH UNIDIRECTIONAL FLOW FROM 1-5KM. MID LEVEL DRYING OVER
NORTHERN IL NOTED ON WATER VAPOR MAY MAY ALLOW FOR ADDITIONAL
EVAPORATIVE COOLING/HIGHER DCAPE VALUES ENHANCING THE WIND DAMAGE
POTENTIAL WHICH IS ALREADY NON-TRIVIAL GIVEN THE VERY STRONG WIND
FIELDS.

ANOTHER ITEM OF NOTE IS APPARENTLY OUTFLOW BOUNDARY EVIDENT ON
VISIBLE SATELLITE IMAGERY ARCING SOUTHWESTWARD ACROSS NORTHERN
ILLINOIS. SURFACE WINDS BACK SLIGHTLY TO THE NORTH OF THIS
BOUNDARY...HOWEVER 0-1KM HELICITY VALUES ARE STILL NOT PARTICULARLY
HIGH. NONE-THE-LESS THE OUTFLOW BOUNDARY LAID OUT PERPENDICULARLY TO
THE ADVANCING CONVECTION WILL PROVIDE AN EXCELLENT SOURCE OF
HORIZONTAL VORTICITY TO BE INGESTED INTO THE LINE AND COULD LEAD TO
A MORE ENHANCED/FOCUSED WIND DAMAGE POTENTIAL. GIVEN THE LOW T/TD
DEPRESSIONS AND STRONG 0-3KM HELICITY THERE WILL BE SOME POTENTIAL
FOR BRIEF TORNADO OR TWO ASSOCIATED WITH ANY OF THE STRONG
MESOVORTICIES ALONG THE LEADING EDGE OF THE LINE...BUT THE PRIMARY
THREAT TODAY WILL CERTAINLY BE DAMAGING WINDS.

IZZI

&&

.DISCUSSION...
355 AM CDT

THREAT OF PERIODIC THUNDERSTORMS AND ACCOMPANYING POTENTIAL FOR
ADDITIONAL MODERATE TO HEAVY RAINFALL TODAY THROUGH FRIDAY NIGHT
REMAINS FORECAST CONCERN.

MULTIPLE SHORT WAVES CONTINUE TO MOVE QUICKLY FROM THE PLAINS
NORTHEASTWARD INTO/TOWARD THE WESTERN GREAT LAKES. ONE THAT BROUGHT
STORMS ACROSS THE AREA LATE WED NIGHT AND EARLY THIS MORNING NOW
MOVING ACROSS LOWER MI WHILE NEXT RIGHT ON ITS HEELS MOVING OUT OF
EASTERN IA. STORMS ACROSS NORTHERN IL AHEAD OF THIS DISTURBANCE WILL
BE EXITING N CENTRAL AND NE IL BEFORE DAYBREAK SO WILL LET EXISTING
FLASH FLOOD WATCH DIE AT 7 AM CDT.

WHILE MULTIPLE SIGNIFICANT THUNDERSTORM OUTFLOWS PUSH SE ACROSS
NORTHERN IL AND NW IN...STRONG LOW LEVEL FLO QUICKLY RECHARGES
UNSTABLE AIRMASS ACROSS CWA AND N ACROSS SRN WI S OF QUASISTATIONARY
FRONT. VIGOROUS TS ACTIVITY HAS MOVED E TO SERN SD AND ERN NEB AS
NEXT SHORT WAVE MOVES FROM THE ROCKIES OVER THE HI PLAINS. AS THIS
DISTURBANCE CONTINUES TO APPROACH THE LOCAL AREA TODAY ANTICIPATE
SIMILAR SCENARIO AS TO WED-WED NIGHT WITH MAIN CONVECTIVE ACTIVITY
REMAINING IN THE VICINITY OF THE SURFACE BOUNDARY WHICH KEEPS THEM
TO THE NW OF THE CWA INTO THIS AFTERNOON. AS THE SHORT WAVE TROF
LIFTS INTO THE UPPER MIDWEST LATE THIS AFTERNOON MID LEVEL UVV OVER
THE CWA INCREASES WHILE STRONG SW LO LEVEL FLO PUMPS PW VALUES INTO
2-2.5 INCH RANGE. NEW FFA WILL MOST LIKELY BE NEEDED BUT WILL HOLD
OFF FOR NOW TO PREVENT OVERLOAD OF VARIOUS HYDROLOGIC
WATCHES...WARNINGS AND STATEMENTS. MENTION OF POSSIBLE ADDITIONAL
HEAVY RAIN IN GRIDS AND TEXT PRODUCTS WILL KEEP WORLD INFORMED OF
CONTINUED POTENTIAL OF ADDITIONAL HEAVY RAIN LATE TODAY AND TONIGHT.
WITH NO SIGNIFICANT CHANGE IN THE PATTERN TODAY THE THREAT OF STRONG
WINDS WITH MORE BOWING SEGMENTS WILL AGAIN BE PRESENT.

HEAVY RAIN AND GUSTY WIND PRODUCING TSRA THREAT CONTINUES FRI AS
ANOTHER SHORT WAVE OR WAVES COME OUT OF THE WESTERN UPPER TROF AND A
WAVE ALONG THE SURFACE FRONT LIFTS FROM IA ACROSS WI AS THE MAIN
UPPER TROF MOVES OVER THE PLAINS. AS THIS TROF MOVES INTO THE
WESTERN GRTLKS LATE FRI NIGHT AND SAT MORNING THE BOUNDARY PUSHES SE
THRU THE CWA IN RESPONSE. THIS FINALLY TURNS OFF THE SPIGOT AS HI
PRES BUILDS SEWRD ACROSS WI AND IA INTO NRN IL DURING THE DAY
FOLLOWING THE UPPER TROF PASSAGE.

TRS

&&

.AVIATION...
113 PM CDT

GENERALLY MOVING INTO ANOTHER CONVECTIVE PATTERN THIS AFTN WITH
STORMS SPREADING FROM IA INTO NRN IL. TSTM TIMING AT TERMINALS FROM
19Z AT RFD TO 22Z AT GYY. CELLS MOVING NEAR 60 MPH SO WINDS MAIN
HAZARD. CIGS AND VSBY VFR EXCEPT WITH TSTM PASSAGE DOWN TO MVFR AND
BRIEFLY PSBL TO IFR. VFR AGAIN THIS EVENING BUT VSBY PSBLY LOWERING
TO MVFR NEAR MRNG. NOTHING IN PROSPECTS FOR STORMS UNTIL ERY AFTN
FRIDAY AHEAD OF FROPA. WINDS GENERALLY SW THRU THE PD WITH GUST TO
25 KTS THIS AFTN...LOWERING TO 10-15 THIS EVENING AND UNDER 10 KTS
AFT MDNGT THRU MID MRNG...THEN BACK TO 10-15 KTS BFR NOONTIME FRIDAY.

RLB

&&

.MARINE...
400 PM CDT

SOUTHWEST WINDS WILL PREVAIL THRU TONIGHT INTO THE MORNING. HOWEVER
A COLD FRONT DROPPING DOWN LAKE MICHIGAN ON FRIDAY WILL SWITCH WINDS
TO MORE NORTHERLY FLOW BY FRIDAY EVENING. COLD AIR ADVECTION COULD
PICK WINDS UP TO 25 KTS BRIEFLY FRIDAY AFTN...WITH WAVES PICKING UP
TO 5 TO 7 FT ON THE SOUTH END. THIS SHUD DIMINISH OVERNIGHT FRIDAY
INTO SATURDAY AS HIGH PRESSURE STARTS BUILDING IN OVER THE LAKES FOR
THE WEEKEND.

RLB

&&

.LOT WATCHES/WARNINGS/ADVISORIES...
IL...FLASH FLOOD WATCH THRU 12Z THURSDAY WINNEBAGO BOONE MCHENRY
     LAKE AND OGLE.
IN...NONE.
LM...SCA IL AND IN NEARSHORES FRI AFTN TO MIDNIGHT FRI NGT.

&&

Hazardous weather outlook, Aug 23, 11:50 AM EST, 3 hours 24 minutes before

HAZARDOUS WEATHER OUTLOOK...UPDATED
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
1150 AM CDT THU AUG 23 2007

ILZ003>006-008-010>014-019>023-032-033-039-INZ001-002-010-011-019-
232130-
WINNEBAGO-BOONE-MCHENRY-LAKE ILLINOIS-OGLE-LEE-DE KALB-KANE-
DUPAGE-COOK-LA SALLE-KENDALL-GRUNDY-WILL-KANKAKEE-LIVINGSTON-
IROQUOIS-FORD-LAKE INDIANA-PORTER-NEWTON-JASPER-BENTON-
1150 AM CDT THU AUG 23 2007

THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR NORTH
CENTRAL AND NORTHEAST ILLINOIS...AND NORTHWEST INDIANA.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

THERE IS A MODERATE RISK OF SEVERE THUNDERSTORMS THIS AFTERNOON AND
TONIGHT OVER MUCH OF NORTHERN ILLINOIS AND NORTHWEST
INDIANA...MAINLY NORTH OF A LINE FROM STREATOR TO KANKAKEE TO
RENSSELAEAR.

SOUTH OF THE MODERATE RISK AREA...EXISTS A SLIGHT RISK THAT COVERS
THE REMAINDER OF NORTHERN ILLINOIS AND NORTHWEST INDIANA.

SHOWERS AND THUNDERSTORMS HAVE DEVELOPED ACROSS EASTERN IOWA THIS
MORNING IN ASSOCIATION WITH A SHORT WAVE TROUGH. THUNDERSTORMS MAY
INTENSIFY AS THEY TRACK INTO NORTHERN ILLINOIS EARLY THIS AFTERNOON.
THE MAIN THREAT WITH THESE STORMS WOULD BE DAMAGING WIND GUSTS AND
HEAVY RAINFALL.

ANOTHER UPPER LEVEL DISTURBANCE IS EXPECTED TO APPROACH NORTHERN
ILLINOIS LATE THIS AFTERNOON AND EVENING. ANOTHER ROUND OF
THUNDERSTORMS IS EXPECTED TO ACCOMPANY THIS DISTURBANCE. DAMAGING
WINDS AND VERY HEAVY RAINFALL APPEAR TO BE THE MAIN THREATS AGAIN
WITH THESE STORMS.

THOSE IN THE THREATENED AREA ARE URGED TO REVIEW SEVERE WEATHER
SAFETY RULES AND TO LISTEN TO RADIO...TELEVISION...AND NOAA WEATHER
RADIO FOR POSSIBLE WATCHES...WARNINGS...AND STATEMENTS LATER TODAY.

ADDITIONAL HEAVY RAINFALL IS ALSO LIKELY WITH THESE STORMS.  THIS
MAY FURTHER AGGRAVATE EXISTING FLOOD PROBLEMS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

THERE IS A SLIGHT RISK OF SEVERE THUNDERSTORMS ACROSS THE ENTIRE
REGION ON FRIDAY.

ADDITIONAL PERIODS OF THUNDERSTORMS ARE EXPECTED FRIDAY INTO EARLY
SATURDAY MORNING. HEAVY RAINFALL WILL BE POSSIBLE DURING THIS
PERIOD. THERE IS ALSO THE POTENTIAL THAT STRONGER STORMS COULD
PRODUCE DAMAGING WINDS.

THERE WILL BE A CHANCE OF THUNDERSTORMS WEDNESDAY.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL LIKELY BE NEEDED THIS AFTERNOON AND EVENING.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

LMZ740>745-766-232130-
WINTHROP HARBOR TO WILMETTE HARBOR IL-
WILMETTE HARBOR TO NORTHERLY ISLAND IL-
NORTHERLY ISLAND TO CALUMET HARBOR IL-
CALUMET HARBOR IL TO GARY IN-
GARY INDIANA TO BURNS HARBOR-
BURNS HARBOR TO MICHIGAN CITY-
LAKE MICHIGAN IL AND IN OPEN WATERS-
1145 AM CDT THU AUG 22 2007

THIS PORTION OF THE HAZARDOUS WEATHER OUTLOOK IS FOR THE ILLINOIS
AND INDIANA WATERS OF LAKE MICHIGAN.

.DAY ONE...THIS AFTERNOON AND TONIGHT.

PERIODS OF THUNDERSTORMS WILL CONTINUE ACROSS THE ILLINOIS WATERS OF
LAKE MICHIGAN THIS AFTERNOON AND TONIGHT. SOME STORMS MAY PRODUCE
LOCAL WIND GUSTS TO 50 KNOTS AND INTENSE LIGHTNING.

BOATERS ON SOUTHERN LAKE MICHIGAN SHOULD MONITOR FORECASTS AND
LISTEN FOR LATER STATEMENTS AND POSSIBLE MARINE WARNINGS.

.DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY.

ADDITIONAL PERIODS OF THUNDERSTORMS ARE EXPECTED FRIDAY INTO EARLY
SATURDAY MORNING. THE THREAT OF STRONG WINDS FROM STRONGER STORMS
WILL CONTINUE.

THERE WILL BE A CHANCE OF THUNDERSTORMS WEDNESDAY.

&&

COMPLETE FORECAST INFORMATION IS AVAILABLE ON THE NWS CHICAGO
WEBPAGE: WEATHER.GOV/CHICAGO

In the hours before

Local storm report, Aug 23, 3:00 PM EST, 14 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
300 PM CDT THU AUG 23 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0255 PM     FUNNEL CLOUD     MAPLE PARK              41.91N 88.59W
08/23/2007                   KANE               IL   TRAINED SPOTTER

            ROTATING WALL CLOUD AT US 38 AND KANE COUNTY LINE

0225 PM     TSTM WND DMG     PERU                    41.34N 89.13W
08/23/2007                   LA SALLE           IL   PUBLIC

            SEVERAL LARGE TREES DOWN BLOCKING SHOOTING PARK ROAD IN
            PERU...AND BUCKLIN AND ROOSELVELT STREETS IN LA SALLE

&&

ALLSOPP

Local storm report, Aug 23, 3:02 PM EST, 12 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
302 PM CDT THU AUG 23 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0255 PM     FUNNEL CLOUD     4 W GENEVA              41.88N 88.39W
08/23/2007                   KANE               IL   TRAINED SPOTTER

            ROTATING WALL CLOUD 1 MILE SOUTH OF US 38

&&

ALLSOPP

Local storm report, Aug 23, 3:05 PM EST, 9 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
305 PM CDT THU AUG 23 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0302 PM     FUNNEL CLOUD     SUGAR GROVE             41.77N 88.46W
08/23/2007                   KANE               IL   LAW ENFORCEMENT

            AT INTERSTATE 88 AT SUGAR GROVE

0302 PM     TSTM WND GST     BATAVIA                 41.85N 88.30W
08/23/2007  M62 MPH          KANE               IL   LAW ENFORCEMENT

            FROM KANE COUNTY EOC

&&

ALLSOPP

Local storm report, Aug 23, 3:06 PM EST, 8 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
306 PM CDT THU AUG 23 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0305 PM     FUNNEL CLOUD     WEST CHICAGO            41.89N 88.22W
08/23/2007                   DUPAGE             IL   TRAINED SPOTTER

            ROTATING WALL CLOUD

&&

ALLSOPP

Local storm report, Aug 23, 3:11 PM EST, 3 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
311 PM CDT THU AUG 23 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0310 PM     FUNNEL CLOUD     ST. CHARLES             41.92N 88.30W
08/23/2007                   KANE               IL   EMERGENCY MNGR

            ROTATING WALL CLOUD IL RTE 64 AND TAYLOR

&&

ALLSOPP

Local storm report, Aug 23, 3:14 PM EST, 0 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHICAGO/ROMEOVILLE IL
314 PM CDT THU AUG 23 2007

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0310 PM     TSTM WND GST     ELGIN                   42.04N 88.29W
08/23/2007  E75 MPH          KANE               IL   PUBLIC

&&

ALLSOPP

The radar

The Chicago radar (KLOT), 124 km away, was scanning. The volume nearest the first event began at 20:14 UTC.

Open the radar archive at this moment

Event by event

12 thunderstorm wind, 3 flood, 1 hail, 1 flash flood. Local standard time, as filed.

Hail, Benton

When: August 23, 3:14 PM EST to 3:16 PM EST
Where: Benton County, 2 mi N of Fowler
Measured: 0.75 in hail
Reported by: Emergency Manager
Coordinates: 40.649, -87.320

Thunderstorm Wind, Lake

When: August 23, 2:40 PM CST
Where: Lake County, Munster
Measured: 56 kt (64 mph) estimated gust
Reported by: Public
Coordinates: 41.570, -87.520

Tree limbs blown down.

Thunderstorm Wind, Lake

When: August 23, 2:43 PM CST
Where: Lake County, Dyer
Measured: 50 kt (58 mph) estimated gust
Reported by: Trained Spotter
Coordinates: 41.500, -87.530

Large tree limbs blown down at Arrowhead and Calumet Roads.

Thunderstorm Wind, Lake

When: August 23, 2:43 PM CST
Where: Lake County, Hammond
Measured: 55 kt (63 mph) estimated gust
Property damage: $10,000
Reported by: Trained Spotter
Coordinates: 41.580, -87.480

A large A-frame sign was blown down at Route 41 and Interstate 80/94.

Thunderstorm Wind, Lake

When: August 23, 2:45 PM CST
Where: Lake County, Merrillville
Measured: 70 kt (81 mph) estimated gust
Property damage: $500,000
Reported by: Fire Department/Rescue
Coordinates: 41.480, -87.330

Numerous large trees blown down...some on homes and cars, 30 to 40 inch diameter trees blown down, some uprooted and some snapped. Significant damage to some homes.

Thunderstorm Wind, Lake

When: August 23, 2:45 PM CST
Where: Lake County, Lowell
Measured: 50 kt (58 mph) estimated gust
Reported by: Emergency Manager
Coordinates: 41.280, -87.420

Six inch diameter tree limb blown down.

Thunderstorm Wind, Lake

When: August 23, 2:45 PM CST
Where: Lake County, Gary Municipal Arpt
Measured: 50 kt (58 mph) measured gust
Property damage: $1.0 million
Reported by: AWOS
Coordinates: 41.620, -87.420

Measured gust to 58 mph at Gary Airport. A hangar under construction was damaged.

Thunderstorm Wind, Lake

When: August 23, 2:48 PM CST
Where: Lake County, Schererville
Measured: 52 kt (60 mph) estimated gust
Reported by: Trained Spotter
Coordinates: 41.500, -87.450

Estimated gust to 60 mph south of Route 30 and east of Route 41.

Thunderstorm Wind, Lake

When: August 23, 2:51 PM CST
Where: Lake County, Gary
Measured: 52 kt (60 mph) estimated gust
Reported by: Trained Spotter
Coordinates: 41.620, -87.350

Estimated gust to 60 mph in downtown Gary.

Thunderstorm Wind, Porter

When: August 23, 3:01 PM CST
Where: Porter County, 2 mi E of Valparaiso
Measured: 70 kt (81 mph) estimated gust
Reported by: Trained Spotter
Coordinates: 41.470, -87.011

Estimated gust to 80 mph in rural Washington Township.

Thunderstorm Wind, Porter

When: August 23, 3:12 PM CST
Where: Porter County, Valparaiso
Measured: 70 kt (81 mph) estimated gust
Reported by: Trained Spotter
Coordinates: 41.470, -87.050

Trees blown down near Route 30 and Horseprairie Road, winds estimated to 80 mph.

Thunderstorm Wind, Porter

When: August 23, 3:12 PM CST
Where: Porter County, Valparaiso Muni Arpt
Measured: 52 kt (60 mph) measured gust
Reported by: ASOS
Coordinates: 41.450, -87.000

Measured gust to 60 mph.

Thunderstorm Wind, Newton

When: August 23, 7:00 PM CST
Where: Newton County, Thayer
Measured: 55 kt (63 mph) estimated gust
Property damage: $3,000
Reported by: Law Enforcement
Coordinates: 41.170, -87.330

Trees and power lines blown down blocking roadways.

Flash Flood, Lake

When: August 23, 7:12 PM CST to August 24, 1:00 AM CST
Where: Lake County, St John
Cause: Heavy Rain
Reported by: Public
Coordinates: 41.450, -87.470

Streets closed due to flooding.

Flood, Porter

When: August 24, 1:43 AM CST
Where: Porter County, 5 mi W of Valparaiso
Cause: Heavy Rain
Deaths: 0 direct, 2 indirect
Injuries: 0 direct, 1 indirect
Property damage: $25,000
Reported by: Newspaper
Coordinates: 41.470, -87.147

A van drove into eight inches of flood water, lost control, crossed the median into westbound lanes and was hit by a semi-trailer. Two passengers were killed and the driver was critically injured.

Flood, Lake

When: August 24, 9:00 AM CST to August 25, 7:00 AM CST
Where: Lake County, Hammond to Hobart
Cause: Heavy Rain
Property damage: $1.0 million
Reported by: Newspaper
Coordinates: 41.580, -87.480

Significant flooding occurred across parts of northwest Indiana due to heavy rains that fell during the evening of August 23rd, on top of already saturated soil. Interstate 80/94 at Kennedy Avenue was flooded with all eastbound lanes closed and two westbound lanes closed. In Merrillville, the Broadfield subdivision was flooded, several feet deep after retention ponds overflowed. Across northern Lake County, hundreds of basements were flooded and numerous roads were closed due to flooding. Many locations received 3 to 5 inches of rain.

Flood, Lake

When: August 24, 12:00 PM CST to August 25, 7:00 AM CST
Where: Lake County, Dyer
Cause: Heavy Rain
Property damage: $4.0 million
Reported by: Broadcast Media
Coordinates: 41.500, -87.530

St. Margaret Mercy Hospital in Dyer Indiana suffered significant flooding around noon on Friday, August 24th, about 20 hours after the heavy rains fell, when Hart Ditch overflowed it's banks. Sixty seven patients were evacuated from the healthcare center when it was apparent that floodwaters entering the building would submerge the Hospital’s emergency generators and cutoff the buildings power supply. The first floor suffered significant water damage. More than 150 homes near the creek also sustained some type of flood damage. US 30 at Plum Creek was closed due to flooding. Numerous cars were also damaged by flood waters.

The people who died

As the offices recorded each death: direct deaths were caused by the weather itself, indirect ones by something it set in motion.

Event	Date	Age	Sex	Where	Kind
Flood, Porter	2007-08-24	38	Male	Vehicle/Towed Trailer	Indirect
Flood, Porter	2007-08-24	39	Male	Vehicle/Towed Trailer	Indirect

What these are

Hail: Hail three-quarters of an inch or larger, or smaller hail that caused damage, filed with the largest stone measured.
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.
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.
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 Indiana in 2007 Every state in 2007 This day in weather history Warnings in Indiana, August 2007

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: 55210, 55215, 55216, 55217, 55213, 55219, 55227, 55231, 55232, 55233, 55221, 55234, 55224, 55235, 56150, 56142, 56135.