Several rivers went into flood across central and northern Iowa due to heavy rains received during the month of September, especially during the middle to latter portion of the month. Two of the rivers, the Iowa River at Tama Highway E49 and the Cedar River at Cedar Falls, remained in flood until early October.
Every event with a place to put it. Tap one for its entry below.
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.
The episode as NWS DMX wrote it up.
Several rivers went into flood across central and northern Iowa due to heavy rains received during the month of September, especially during the middle to latter portion of the month. Two of the rivers, the Iowa River at Tama Highway E49 and the Cedar River at Cedar Falls, remained in flood until early October.
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 Des Moines, IA wrote its last area forecast discussion before the first event at Sep 22, 2:44 AM CST, 52 minutes earlier.
AREA FORECAST DISCUSSION National Weather Service Des Moines IA 344 AM CDT Thu Sep 22 2016 .SHORT TERM.../Today/ Issued at 342 AM CDT Thu Sep 22 2016 Ongoing convection continues in axis of low level jet inflow across northern iowa and additionally supported by weak wave entering western Iowa. Most intense convection is occurring behind a slowly advancing outflow the only recently became observable on radar. Rainfall rates in strongest areas remain 2-3 inches per hour and this concern will persist through sunrise although the slow southward progress should help any one area from getting as dramatic amounts as seen last evening near Charles City. That being said, the threat still exists for flash flooding across northern Iowa through the day and the headline will continue unchanged at this point. Still difficult to see evolution of convection later today as current convection gradually diminishes with the passage of the weak wave this morning. Where the surface and outflow end up and eventually provide focus for additional development is still being considered. It will likely remain somewhere across northern half of Iowa by later this afternoon with additional threat of heavy rain and strong storms. Temperatures today will remain cooler across the north where outflow will be south of area with a modified airmass in place. Farther south, will continue to see an unseasonably warm and humid airmass in southern Iowa with temperatures remaining nearly 15 degrees above normal. .LONG TERM.../Tonight through Wednesday/ Issued at 342 AM CDT Thu Sep 22 2016 The main forecast concern was focused on additional heavy rain chances tonight and again Saturday night into Sunday. Models have become into better overall agreement throughout the forecast period with the ECMWF following the GFS on its respective solution next week. Leaned closer to the GFS Tonight into Friday...With the boundary remaining planted across northern Iowa and another shortwave to eject across the Central Plains tonight combined with the increasing LLJ, another round of storms, possibly heavy rain, looks probable for northern portions of Iowa. Fairly strong QG forcing moves across northern Iowa this evening with good isentropic upglide along the 300-310K surface. Decent moisture transport overrunning the surface boundary providing some moisture convergence across northern Iowa. PWATs remain well above normal for late September as they range near 2 inches by 06z Friday. Warm layer cloud depths over 4000 meters and with BUFR soundings at MCW to FRM remaining deeply saturated, additional heavy rain is possible over portions that have already received significant rainfall. Thus, flash flooding as well as river flooding could be exacerbated even further by Friday morning. Storms look to quickly diminish past 12z Friday with the LLJ diminishing. Saturday through Monday...cold front and associated upper level low pressure will transition across the region Saturday night into Sunday. The best potential for rain looks to be from 00-12z Sunday and unfortunately another long duration round of rainfall possible. Instability is weak as well as the deep layer shear ranging less than 20 knots Saturday night. Low confidence with any widespread severe storms. Thus, the main concern is the heavy rain potential with similar PWATs and warm layer cloud depths compared to tonight. The GFS/ECWMF 00z runs have dried out Monday but with some lingering low stratus in the CAA and cannot rule out some scattered showers during the day Monday into Monday night. Tuesday through Thursday...The remainder of the week remains uncertain with the models continue to inconsistent with their respective solutions. However, confidence is increasing toward a dry and cool than wet and cool solution. && .AVIATION.../For the 06Z TAFS through 06Z Thursday night/ Issued at 1152 PM CDT Wed Sep 21 2016 Additional thunderstorms are expected to spread across northern Iowa late tonight and linger into Thursday. Have included VCTS at the northern sites where thunder is more likely, compared to the VCSH at KDSM during the morning hours Thursday. Southerly winds expected to transition to more southeasterly to easterly toward Thursday evening. && .HYDROLOGY... Issued at 342 AM CDT Thu Sep 22 2016 While the overall threat in southern portions of the watch seem to be waning, recent storm motion should carry convection into this portions of the watch this morning with some limited threat. Therefore will maintain the watch for now. As mentioned in the body of the discussion above, eventually placement of outflow/boundary by this afternoon will determine where eventual redevelopment will take place later today. It still appears this should be across the northern half of the state and therefore will leave headline alone. May need to be extended into tonight if the threat is deemed sufficient later today. && .DMX WATCHES/WARNINGS/ADVISORIES... Flash Flood Watch through this evening for IAZ004>007-015>017- 023>028-033>039-044>048. && SHORT TERM...Cogil LONG TERM...Podrazik AVIATION...Beerends HYDROLOGY...Cogil
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 1147 PM CDT WED SEP 21 2016 IAZ004>007-015>017-023>028-033>039-044>048-221000- EMMET-KOSSUTH-WINNEBAGO-WORTH-PALO ALTO-HANCOCK-CERRO GORDO- POCAHONTAS-HUMBOLDT-WRIGHT-FRANKLIN-BUTLER-BREMER-SAC-CALHOUN- WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK-CRAWFORD-CARROLL-GREENE- BOONE-STORY- 1147 PM CDT WED SEP 21 2016 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TONIGHT HEAVY RAIN IS ANTICIPATED AND A FLASH FLOOD WATCH REMAINS IN EFFECT FOR THE AREA THROUGH THURSDAY EVENING. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY ADDITIONAL THUNDERSTORMS WITH HEAVY RAIN AND ISOLATED SEVERE WEATHER ARE EXPECTED ON THURSDAY INTO THURSDAY EVENING. THE NEXT POTENTIAL FOR STORMS IS FORECAST SATURDAY NIGHT INTO SUNDAY. THE PREDICTABILITY FOR SEVERE WEATHER REMAINS TOO LOW AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED AT TIMES THROUGH THURSDAY. IAZ049-050-057>062-070>075-081>086-092>097-221000- MARSHALL-TAMA-AUDUBON-GUTHRIE-DALLAS-POLK-JASPER-POWESHIEK-CASS- ADAIR-MADISON-WARREN-MARION-MAHASKA-ADAMS-UNION-CLARKE-LUCAS- MONROE-WAPELLO-TAYLOR-RINGGOLD-DECATUR-WAYNE-APPANOOSE-DAVIS- 1147 PM CDT WED SEP 21 2016 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TONIGHT A CHANCE OF THUNDERSTORMS IS FORECAST OVERNIGHT TONIGHT INTO THURSDAY MORNING. THE SEVERE WEATHER POTENTIAL REMAINS LOW AT THIS TIME. LOCALLY BRIEF HEAVY RAIN IS POSSIBLE. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THUNDERSTORMS WITH LOCALLY HEAVY RAIN AND ISOLATED SEVERE WEATHER ARE POSSIBLE ON THURSDAY INTO THURSDAY EVENING. THE NEXT POTENTIAL FOR STORMS IS FORECAST SATURDAY NIGHT INTO SUNDAY. THE PREDICTABILITY FOR SEVERE WEATHER REMAINS TOO LOW AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED AT TIMES THROUGH THURSDAY. MJB
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
1047 PM CDT WED SEP 21 2016
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
1047 PM HEAVY RAIN GREENE 42.90N 92.80W
09/21/2016 M7.50 INCH BUTLER IA FIRE DEPT/RESCUE
STORM TOTAL.
&&
MJBPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
150 AM CDT THU SEP 22 2016
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0147 AM FLASH FLOOD GREENE 42.90N 92.80W
09/22/2016 BUTLER IA EMERGENCY MNGR
MULTIPLE HOMES IN GREENE NOW BEING IMPACTED
BY FLOODWATERS FROM THE RAPIDLY RISING SHELL
ROCK RIVER. EM ESTIMATES THAT THE RIVER IS
NEAR THE LEVEL IT REACHED IN 2008.
&&
NWS DES MOINES IA
IRIS SYSTEMThe national radar mosaic for the moment the first event began.
9 flood. Local standard time, as filed.
The Winnebago River at Mason City crested at 14.14 feet on 22 September 2016 at 6:15 pm CDT.
The Shell Rock River at Shell Rock crested at 21.51 feet on 23 September 2016 at 2:08 pm CDT.
The Cedar River at Cedar Falls crested at 98.90 feet on 24 September 2016 at 12 pm CDT. The river remained in flood at Cedar Falls into early October.
The Cedar River at Janesville crested at 16.35 feet on 23 September 2016 at 10:30 pm CDT.
The Cedar River at Waterloo crested at 22.95 feet on 24 September 2016 at 4 pm CDT.
The Iowa River at Rowan crested at 14.47 feet on 24 September 2016 at 2 pm CDT.
Black Hawk Creek at Hudson crested at 14.51 feet on 26 September 2016 at 7:45 am CDT.
The Boone River at Webster City crested at 14.20 feet on 25 September 2016 at 1015 pm CDT.
The Iowa River at Tama Highway E49 crested at 13.26 feet on 29 September 2016 at 10:30 pm CDT. The river remained in flood into early October.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2016Every state in 2016This day in weather historyWarnings in Iowa, September 2016
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: 658428, 658432, 658422, 658426, 658421, 658430, 658424, 658435, 658434.