A considerable amount of snow had accumulated during the previous winter across northern Iowa and southern Minnesota. As the snow melted, river levels rose across northern Iowa with numerous sites reaching minor to moderate flood levels.
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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.
A considerable amount of snow had accumulated during the previous winter across northern Iowa and southern Minnesota. As the snow melted, river levels rose across northern Iowa with numerous sites reaching minor to moderate flood levels. A couple of the sites, most notably Estherville and Cedar Falls, briefly reached low end major levels. It was fortunate that the snow melted relatively slowly and also the fact that no significant rainfall occurred during the melt. Rainfall that occurred later in the month was held in check by sub-freezing temperatures. The fact that reduced the flooding was a cold spell that moved into the state after the 22nd. Temperatures were highly variable during the month as is typical for this time of year as the weather transitions from winter to spring. A very mild period prevailed from the 14th through the 22nd but was followed by nine consecutive colder than normal days to finish out the month. Sibley recorded the March’s lowest temperature with a low of -5 on the 2nd while Shenandoah and Sidney tied for the highest temperatures with 81 readings on the 22nd. Temperatures for the month as a whole averaged slightly below normal over the northwest and a little above normal over the southeast. Precipitation was fairly evenly distributed throughout the month and was generally greater than normal over the northeast one-third of Iowa and well below normal over the western third of the state. About half of the month’s precipitation came in two storms. The first storm, on the 8th-9th, started with rain statewide but transitioned to snow over the northwestern two-thirds of Iowa. Greatest snow amounts of three to five inches fell over north central and northeast Iowa while rain totals locally exceeded an inch over the southeast. The second event on the 22nd-23rd brought thunderstorms and rainfall statewide with rain amounts up to two inches over parts of north central Iowa. Damage from the river flooding was limited to agricultural areas for the most part. Considerable advance preparation in more flood prone areas also helped to reduce losses.
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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 Mar 16, 11:01 PM CST, 1 hour 45 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 1201 AM CDT THU MAR 17 2011 .SHORT TERM /TONIGHT/... SOUTHERLY FLOW WILL INCREASE TONIGHT AS LOW PRESSURE TO THE WEST MOVES EAST. ALONG WITH THE THE INCREASE IN SOUTHERLY FLOW AND MORE MILD OVERNIGHT TEMPS WILL COME A INCREASED MOISTURE AS WELL. SFC OBS CONTINUED TO SHOW A NARROW AREA OF 50 DEGREE DEWPOINTS WORKING UP FROM OK AND THIS SHOULD ENTER THE CWA AFT 06Z...MORE LIKELY IN THE 09Z-12Z TIMEFRAME. AS A RESULT...I HAVE INCREASED CLOUDS OVERNIGHT. ABUNDANT LOW LEVEL MOISTURE SUGGESTS DRIZZLE/FOG SCENARIO TOWARDS MORNING. THE CAVEAT IS THE STRONG WINDS WHICH MAY PRODUCE MORE MIXING THAN THE MODELS SUGGEST. FOR NOW I WENT WITH A MORE PESSIMISTIC APPROACH. THUS TEMPS ARE ALSO AFFECTED. IF SKIES STAY CLEAR ALL NIGHT...WE WILL BE TOO WARM. .LONG TERM /THURSDAY THROUGH WEDNESDAY/... MAIN CHALLENGES CONTINUE TO BE THE TIMING AND LOCATION OF SYSTEMS IN THE LONG TERM...AS WELL AS MAX TEMPS COMING UP FOR THE NEXT SEVERAL DAYS AND STRATUS TOMORROW MORNING. SUBJECTIVE SFC ANALYSIS CONTINUES TO SHOW MOISTURE STREAMING ACROSS TEXAS AND OKLAHOMA WITH DEW POINTS IN THE MID 40S TO LOWER 50S ADVANCING QUICKLY NORTH. AREAS OF CUMULUS HAVE DEVELOPED WITH SOME LOW TO MID LEVEL CLOUDS MOVING IN AT H900 TO H850 LEVELS. CHALLENGE THROUGH TOMORROW MORNING IS THE POTENTIAL FOR ISOLATED CONVECTION VERSUS LOWER STRATUS AND DRIZZLE/SHOWERS. NAM/GFS AT ODDS WITH EXTENT OF STRATUS WHILE THE EURO CONTINUES TO SUGGEST SOME ELEVATED CONVECTION AFT 12Z. FOR NOW...WILL LEAVE ISO THUNDER OUT OF THURSDAY TIMEFRAME WITH SOME DOUBTS THAT ANYTHING WILL GET GOING UNTIL EARLY EVENING SOUTHEAST. THE NEXT WAVE ARRIVES SAT NIGHT AND IN BETWEEN COOLER AIR WILL FILTER IN ACROSS THE REGION FOR FRIDAY AND SATURDAY. TOWARD THE END OF THE WEEKEND TWO MORE SIGNIFICANT SYSTEMS WILL AFFECT THE REGION WITH BETTER POTENTIAL FOR THUNDER AND MODERATE RAINFALL ACROSS THE REGION. HAVE BEEFED UP THUNDER CHANCES FOR SUNDAY THROUGH TUESDAY AS EURO CONTINUES TO SUGGEST FARTHER NORTH AND WEST STORM TRACK KEEPING THE REGION IN STRONGER JET DYNAMICS AND GREATER INSTABILITY. A LOT OF UNCERTAINTY REMAINS FOR NOW...AND WILL BE ADDRESSED IT IN MORE DETAIL IN THE NEXT SEVERAL PACKAGES. BY THE END OF THE EXTENDED... TEMPERATURES SLIDE OFF ON WEDNESDAY AS ANOTHER SHOT OF COOL AIR ADVANCES SOUTH INTO THE FORECAST AREA. && .HYDROLOGY...15/19Z ...SNOW MELT RISES ON OUR RIVERS WILL BEGIN OVER THE NEXT TWO DAYS... THE FINAL MAJOR SNOW MELT OF THE SEASON FROM SOUTH DAKOTA INTO MINNESOTA IS BEGINNING...OWING TO FORECAST TEMPERATURES FROM TODAY THROUGH THE END OF THE WEEK. THE ACTUAL AMOUNT OF THE RISES ON OUR RIVERS...AND SUBSEQUENT FLOODING POTENTIAL...IS MORE UNCERTAIN. RISES ON RIVERS IN OUR NORTHERN CWA HAVE BEGUN. CURRENT SIMULATIONS ARE CALLING FOR MODERATE FLOODING AT LOCATIONS ON THE WEST FORK DES MOINES RIVER...AND MINOR FLOODING ON THE WINNEBAGO AND EAST FORK DES MOINES RIVERS. THESE RIVERS ARE FORECAST TO REACH FLOOD STAGE AS EARLY AS THURSDAY EVENING...AND LATER AT SOME SOME LOCATIONS. IN THE COMING DAYS...OUR RIVER MODEL WILL FORECAST ADDITIONAL FLOODING AT MORE LOCATIONS AND ON MORE STREAMS. SOME UNCERTAINTY EXISTS IN THESE FORECASTS PRESENTLY. THUS...WE HAVE NOT YET ISSUED RIVER FLOOD WARNINGS FOR ALL THE SITES...BUT HAVE ISSUED A RIVER FLOOD WARNING FOR THE WEST FORK OF THE DES MOINES RIVER AT ESTHERVILLE. FOR THE OTHER SITES...WE HAVE OPTED TO ISSUE A HYDROLOGIC OUTLOOK FOR NOW. THE SNOW PACK FROM SOUTH DAKOTA INTO MINNESOTA HAS NOT STARTED TO MELT IN EARNEST YET...SO SOME UNCERTAINTY EXISTS IN EXACTLY HOW THE SNOW PACK WILL RESPOND TO THE FORECAST WARMER TEMPERATURES. ADDITIONAL UNCERTAINLY EXISTS IN HOW THE RIVERS WILL RESPOND TO THIS SNOW MELT. IN OTHER WORDS...HOW FAST WILL THE WATER FROM THE SNOW MELT MAKE IT INTO THE RIVERS. FOR EXAMPLE...SINCE THE SNOW ARRIVED RATHER EARLY LAST SEASON FROM SOUTH DAKOTA INTO MINNESOTA...THE FROST DEPTHS IN THAT REGION ARE NOT AS DEEP AS NORMAL. THIS MEANS THAT MORE WATER MAY INFILTRATE INTO THE GROUND THAN WHAT IS PRESENTLY EXPECTED. IF THIS DOES HAPPEN...THEN THE RIVERS WOULD BE SLOWER TO RISE...CREST AND FALL THAN PRESENTLY FORECAST. ANOTHER CONTRIBUTING FACTOR TO THE UNCERTAINTY IS FORECAST RAINFALL. THE WEATHER PATTERN IS EXPECTED TO BECOME MORE ACTIVE BY LATE THIS COMING WEEKEND AND CONTINUE INTO NEXT WEEK...WHICH MAY BRING SEASONALLY MODERATE TO HEAVY RAINFALL TO OUR REGION. THE PRESENT FORECASTS DO NOT TAKE THIS POTENTIAL RAINFALL INTO ACCOUNT GIVEN ITS UNCERTAINTY. DEPENDING ON THE TIMING...AMOUNT AND LOCATION OF THIS RAINFALL...IT MAY LEAD TO QUICKER RISES...SLOWER FALLS...OR A WORST CASE SCENARIO WOULD BE HIGHER CRESTS. AT THIS TIME THERE IS A LOW PROBABILITY THAT THE LATTER WOULD OCCUR. AS ALWAYS...REFER TO OUR AHPS RIVER WEB PAGES FOR MORE INFORMATION ON RIVER FORECASTS. GO TO OUR WEB SITE AT WEATHER.GOV/DESMOINES THEN CLICK ON THE OPTION FOR RIVERS & LAKES ON THE LEFT HAND MENU. && .FIRE WEATHER...16/20Z BREEZY CONDITIONS AND A RELATIVELY DRY AIR MASS WILL CONTINUE ACROSS WEST CENTRAL PORTIONS IOWA THROUGH 7 PM. THE WIND WILL DIMINISH AFTER 7 PM. THE VERY HIGH RISK OF FIRE DANGER WILL REMAIN ACROSS THE FAR WEST THROUGH 7 PM. REFER TO DSMRFDDMX FOR FURTHER DETAILS. && .AVIATION...17/06Z MOISTURE A LITTLE SLOWER THAN PREVIOUSLY THOT IN GETTING INTO IA AND HAVE DELAYED THE MVFR CONDS UNTIL 12Z OR SHORTLY AFT. A FEW SHWRS ARE POSSIBLE OVR THE NRN TAFS IN THE MRNG BFR WSHFT LINE MOVS IN. STRONG FLOW ALF HAS SET UP AND HAVE CARRIED LLWS IN TAF SITES THAT HAVE DECOUPLED. THE STRONG FLOW SHOULD WEAKEN AROUND SNRS AND DID NOT CARRY INTO THE MORNING FOR THAT REASON. VFR CONDS WILL SPREAD IN AS WINDS SHFT TO THE NW THU AFTN WITH VFR CONDS REACHING KOTM TOWARD 00Z/18. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...MS MAR 11 AVIATION...MS MAR 11 LONG TERM...REV HYDROLOGY...REV FIRE WX...FAB
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 456 AM CDT WED MAR 16 2011 IAZ047>050-059>062-073>075-084>086-095>097-171100- BOONE-STORY-MARSHALL-TAMA-DALLAS-POLK-JASPER-POWESHIEK-WARREN-MARION- MAHASKA-LUCAS-MONROE-WAPELLO-WAYNE-APPANOOSE-DAVIS- 456 AM CDT WED MAR 16 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THERE IS A CHANCE OF AN ISOLATED THUNDERSTORM THURSDAY AND THURSDAY NIGHT. AT THIS TIME THE CHANCE FOR SEVERE WEATHER IS MINIMAL. THERE ARE ADDITIONAL THUNDERSTORM CHANCES SUNDAY THROUGH TUESDAY. AT THIS TIME IT IS TOO EARLY TO DETERMINE THE THREAT OF SEVERE WEATHER...THOUGH SOME SEVERE WEATHER MAY OCCUR SUNDAY NIGHT. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED. IAZ004>007-016-017-024>028-035>039-171100- EMMET-KOSSUTH-WINNEBAGO-WORTH-HANCOCK-CERRO GORDO-HUMBOLDT-WRIGHT- FRANKLIN-BUTLER-BREMER-WEBSTER-HAMILTON-HARDIN-GRUNDY-BLACK HAWK- 456 AM CDT WED MAR 16 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THERE IS A CHANCE FOR SOME THUNDERSTORM ACTIVITY ACROSS THE AREA SUNDAY INTO TUESDAY. AT THIS TIME IT IS TOO EARLY TO DETERMINE THE THREAT OF SEVERE WEATHER...THOUGH SOME SEVERE WEATHER MAY OCCUR SUNDAY NIGHT. THE CHANCE FOR RAINFALL THIS WEEKEND INTO EARLY NEXT WEEK...COMBINED WITH SNOW MELT IN MINNESOTA...MAY LEAD TO MINOR TO MODERATE RIVER FLOODING ALONG STREAMS AND RIVERS IN NORTHERN IOWA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED. IAZ015-023-033-034-044>046-057-058-070>072-081>083-092>094-171100- PALO ALTO-POCAHONTAS-SAC-CALHOUN-CRAWFORD-CARROLL-GREENE-AUDUBON- GUTHRIE-CASS-ADAIR-MADISON-ADAMS-UNION-CLARKE-TAYLOR-RINGGOLD- DECATUR- 456 AM CDT WED MAR 16 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TODAY AND TONIGHT DRY AND WARMER CONDITIONS COMBINED WITH GUSTY SOUTHERLY WINDS TODAY COULD LEAD TO A GRASSLAND FIRE DANGER. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY THERE IS A CHANCE FOR SOME THUNDERSTORM ACTIVITY ACROSS THE SOUTH THURSDAY AND AGAIN SATURDAY AFTERNOON. THE THREAT FOR SEVERE WEATHER IS LOW. THERE IS A CHANCE FOR SOME THUNDERSTORM ACTIVITY ACROSS THE AREA SUNDAY INTO TUESDAY. AT THIS TIME IT IS TOO EARLY TO DETERMINE THE THREAT OF SEVERE WEATHER...THOUGH SOME SEVERE WEATHER MAY OCCUR SUNDAY NIGHT. THE CHANCE FOR RAINFALL THIS WEEKEND INTO EARLY NEXT WEEK...COMBINED WITH SNOW MELT IN MINNESOTA...MAY LEAD TO MINOR TO MODERATE RIVER FLOODING ALONG STREAMS AND RIVERS IN NORTHERN IOWA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION WILL NOT BE NEEDED. AW/ZOGG
The national radar mosaic for the moment the first event began.
2 flood. Local standard time, as filed.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2011Every state in 2011This day in weather historyWarnings in Iowa, March 2011
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: 283414, 283413.