Flooding in Iowa, April 1 to 18, 2006

Name: Flooding in Iowa, April 1 to 18, 2006
Start: 2006-04-01T06:00
End: 2006-04-18T06:00
Location: Iowa

April 1 to 18, 2006 · NWS FSD · 4 events in 4 counties and zones

Heavy rain over the Big Sioux River basin caused the river to rise above flood stage near the beginning of April. The river remained above flood stage for two and a half weeks.

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: None recorded
Crop damage: None recorded
Events: 4

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 FSD wrote it up.

Heavy rain over the Big Sioux River basin caused the river to rise above flood stage near the beginning of April. The river remained above flood stage for two and a half weeks. Flooding was mainly confined to farmland and other lowlands near the river. The flooding damaged some roads, but there were no reports of damage to structures. The amount of damage to farmland was not known. The greatest flooding was reported at Akron, where the river crested at 8.4 feet above flood stage on April 10th, and at Hawarden, where it crested at 7.0 feet above flood stage, also on April 10th.

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 Sioux Falls, SD wrote its last area forecast discussion before the first event at Apr 1, 3:30 AM CST, 2 hours 30 minutes earlier.

Area forecast discussion, Apr 1, 3:30 AM CST, 2 hours 30 minutes before

AREA FORECAST DISCUSSION FOR SOUTHEAST SD/SOUTHWEST MN/NORTHWEST IA
NATIONAL WEATHER SERVICE SIOUX FALLS SD
330 AM CST SAT APR 1 2006

.DISCUSSION...HIGH PRESSURE WILL CONTINUE TO SLIDE EAST ACROSS THE
DAKOTAS THIS MORNING WITH LIGHT WINDS AND SOME PATCHY FOG. STRATUS
HAS BACKED UP INTO ERN SD EARLY THIS MORNING...CLOSE TO WHAT NAM 950
RH FIELD SHOWS. FOLLOWED THE NAM WITH LOW CLOUD DECK SLIDING EAST
AND BREAKING UP OVER THE LATE MORNING HOURS. EVEN AS LOW CLOUDS
BREAK...PLENTY OF CIRRUS WILL WORK INTO THE REGION AHEAD OF NEXT
TROUGH.

MAIN FORECAST FOCUS WILL BE FOR TONIGHT AND SUNDAY WITH ANOTHER LOW
PRESSURE SYSTEM MOVING ACROSS NEBRASKA AND IOWA. SURFACE TROUGH WILL
BEGIN TO DEEPEN OVER THE WRN PLNS DURING THE DAY TODAY AS UPPER
TROUGH SWINGS TROUGH THE ROCKIES. PRESSURE GRADIENT WILL TIGHTEN
WITH SOUTHERLY WINDS RETURNING IN THE MORNING AND INCREASING TROUGH
THE AFTERNOON. WENT ABOVE GUIDANCE WITH WIND MAGNITUDE AS SHOULD BE
ABLE TO MIX DOWN SOME OF THE STRONGER 925 MB WINDS TO THE SURFACE.
WITH SOUTHERLY WINDS...GULF MOISTURE WILL BEGIN TO RETURN IN FULL
DURING THE DAY TODAY. SHOWERS AND THUNDER STORMS ARE EXPECTED TO
DEVELOP IN ERN NEBRASKA THIS EVENING WITH STRONG ISENTROPIC LIFT AND
LOW LEVEL JET...CONVECTION WILL PUSH INTO THE SRN CWA BY LATE
EVENING. NOT ANTICIPATING MUCH IN THE WAY OF SEVERE STORMS GIVEN THE
FORECAST TRACK OF THE LOW...BUT CERTAINLY SOME STRONGER STORMS WILL
BE POSSIBLE ACROSS THE FAR SRN CWA OVERNIGHT. BIGGEST CONCERN IS FOR
THE POTENTIAL OF FLOODING...AS SOILS ARE SATURATED AND MANY STREAMS
AND RIVERS ALREADY AT OR NEAR FLOOD STAGE. DO EXPECT AN INCH OF RAIN
FROM TONIGHT THROUGH SUNDAY EVENING OVER MUCH OF THE ERN CWA...WITH
SOME TWO INCH AMOUNTS POSSIBLE. SOME OF THIS WILL FALL IN AREAS
WHICH RECEIVED ONE TO TWO INCHES WITH THE LAST STORM. MIXING RATIOS
AND PWS SUPPORT THESE AMOUNTS...BOTH NAM AND GFS GIVE PWS OF OVER
AND INCH BY 06Z SUN ACROSS MUCH OF THE CWA. WILL LET DAY SHIFT
DECIDE IF AND WHERE A FLOOD WATCH IS WARRANTED. ALSO...LOOKS LIKE
WIND ADVISORY CRITERIA WILL BE MET ON THE BACK SIDE OF THE LOW
SUNDAY NIGHT AND MONDAY WITH TIGHT PRESSURE GRADIENT AND GOOD CAA.

&&

.FSD WATCHES/WARNINGS/ADVISORIES...
SD...NONE.
MN...NONE.
IA...NONE.
NE...NONE.

&&

LIEBL

Hazardous weather outlook, Apr 1, 5:40 AM CST, 20 minutes before

HAZARDOUS WEATHER OUTLOOK...CORRECTED
NATIONAL WEATHER SERVICE SIOUX FALLS SD
0540 AM CST SAT APR 01 2006

SDZ038>040-050-052>071-MNZ071-072-080-081-089-090-097-098-
IAZ001>003-012>014-020>022-031-032-NEZ013-014-021200-
AURORA-BEADLE-BON HOMME-BROOKINGS-BRULE-BUENA VISTA IA-
CHARLES MIX-CHEROKEE IA-CLAY-CLAY IA-COTTONWOOD MN-DAKOTA NE-
DAVISON-DICKINSON IA-DIXON NE-DOUGLAS-GREGORY-HANSON-HUTCHINSON-
IDA IA-JACKSON MN-JERAULD-KINGSBURY-LAKE-LINCOLN-LINCOLN MN-
LYON IA-LYON MN-MCCOOK-MINER-MINNEHAHA-MOODY-MURRAY MN-NOBLES MN-
OBRIEN IA-OSCEOLA IA-PIPESTONE MN-PLYMOUTH IA-ROCK MN-SANBORN-
SIOUX IA-TURNER-UNION-WOODBURY IA-YANKTON-
0540 AM CST SAT APR 01 2006

THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST SOUTH DAKOTA...
SOUTHWEST MINNESOTA...NORTHWEST IOWA...AND NORTHEAST NEBRASKA.

.DAY ONE...TODAY AND TONIGHT

THUNDERSTORMS...
SHOWERS AND THUNDERSTORMS WILL DEVELOP OVER EASTERN NEBRASKA LATE
THIS AFTERNOON AHEAD OF A LOW PRESSURE SYSTEM MOVING OUT OF THE
CENTRAL ROCKIES. SHOWER AND THUNDERSTORMS WILL MOVE INTO EASTERN
SOUTH DAKOTA...NORTHWEST IOWA...AND SOUTHWEST MINNESOTA THIS
EVENING
INTO THE OVERNIGHT HOURS. THE BULK OF THE THUNDERSTORM ACTIVITY WILL
GENERALLY REMAIN SOUTH OF INTERSTATE 90. SEVERE THUNDERSTORMS
ARE NOT ANTICIPATED AT THIS TIME...HOWEVER SOME STRONGER STORMS WILL
BE POSSIBLE INTO EXTREME SOUTHEAST SOUTH DAKOTA AND NORTHWEST IOWA
TONIGHT.

FLOODING...
MINOR FLOODING WILL CONTINUE ALONG SOME RIVERS AND STREAMS FROM
SOUTHEAST SOUTH DAKOTA INTO NORTHWEST IOWA AND SOUTHWEST
MINNESOTA...DUE TO RAINS RECENT RAINS.

A STRONG LOW PRESSURE SYSTEM WILL MOVE THROUGH THE CENTRAL PLAINS
TONIGHT INTO SUNDAY...PRODUCING WIDESPREAD SHOWERS AND
THUNDERSTORMS. RAINFALL AMOUNTS ACROSS SOUTHEAST SOUTH
DAKOTA...NORTHWEST IOWA...AND SOUTHWEST MINNESOTA ARE EXPECTED TO
REACH ONE INCH IN MANY LOCATIONS. THESE RAINS MAY PUSH ALREADY
SWOLLEN RIVERS AND STREAMS HIGHER.

.DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY

AS LOW PRESSURE EXITS THE REGION SUNDAY NIGHT...STRONG NORTH TO
NORTHWEST WINDS ARE EXPECTED. STRONG WINDS WILL LIKELY CONTINUE
ACROSS MUCH OF THE UPPER MIDWEST TROUGH MONDAY AFTERNOON BEFORE
DIMINISHING MONDAY EVENING.

.SPOTTER INFORMATION STATEMENT...

SPOTTER ACTIVATION WILL NOT BE NEEDED TODAY AND TONIGHT.

&&

FOR MORE INFORMATION PLEASE VISIT OUR WEBSITE AT
WWW.CRH.NOAA.GOV/FSD. THIS INCLUDES THE GRAPHICAL HAZARDOUS
WEATHER OUTLOOK.

LIEBL

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

4 flood. Local standard time, as filed.

Flood, Lyon

When: April 1, 6:00 AM CST to April 9, 6:00 AM CST
Where: Lyon County, Klondike
Reported by: OFFICIAL NWS OBS.
Coordinates: 43.383, -96.533

Flood, Plymouth

When: April 1, 6:00 AM CST to April 18, 6:00 AM CST
Where: Plymouth County, Akron
Reported by: OFFICIAL NWS OBS.
Coordinates: 42.833, -96.550

Flood, Sioux

When: April 1, 6:00 AM CST to April 13, 6:00 AM CST
Where: Sioux County, Hawarden
Reported by: OFFICIAL NWS OBS.
Coordinates: 43.000, -96.467

Flood, Woodbury

When: April 1, 6:00 AM CST to April 18, 6:00 AM CST
Where: Woodbury County, 5 mi NW of Sioux City
Reported by: OFFICIAL NWS OBS.
Coordinates: 42.550, -96.450

What these are

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 Iowa in 2006 Every state in 2006 This day in weather history Warnings in Iowa, April 2006

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: 5502082, 5502083, 5502084, 5502085.