4 below normal. 6 above normal with daily maximum temperatures reaching into the mid 50’s or higher somewhere in the state on the 13th, 15th, 16th, 17th and 20th.
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.
Unseasonably cold weather prevailed for the first ten days of the month with temperatures averaging 11.4 below normal. However the second ten days of the month averaged 11.6 above normal with daily maximum temperatures reaching into the mid 50’s or higher somewhere in the state on the 13th, 15th, 16th, 17th and 20th. The highest temperature was reported from Leon with a 71 reading on the 17th. This was the highest temperature recorded in Iowa so early in the year since a 72 reading at Webster City on January 26, 2002. The relatively warm period at mid-month melted all of the snow pack from about the southwestern two-thirds of Iowa. Unfortunately the warm-up, accompanied by significant rain in many areas on the 20th, resulted in locally severe flooding from ice jams such as the ice jam that impacted the Fort Dodge area. The final eight days of the month averaged slightly colder than normal with no major extremes in temperature. The turnaround in temperatures for the second half of the month started the spring flood season. Though there was a significant amount of water equivalent in the snow over the north half of Iowa, it was fortunate that for the most part there wasn't a great deal of rainfall during the meltdown. There was a significant amount of ice action during the melt with the Fort Dode area seeing the brunt of the ice jam flooding. The bulk of the spring flooding took place in the Des Moines River Basin. Flooding had more of a scattered nature elsewhere. The flood stage was exceeded at several sites, most of the flooding remained below moderate levels.
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 Feb 17, 5:48 PM CST, 4 hours 30 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 548 PM CST THU FEB 17 2011 .SHORT TERM /TONIGHT/... LOW SWINGING ACROSS THE NORTHERN PLAINS NOW WILL PULL A TROUGH INTO THE REGION THIS EVENING. WARMEST AIR WILL SHIFT TO THE EAST THIS EVENING WITH COLD AIR ADVECTION EXPECTED THROUGH THE EVENING AND OVERNIGHT. GRADIENT WINDS WILL CONTINUE TO BE STRONGER ACROSS THE NORTH TONIGHT BUT MIXING DECOUPLES AFTER SUNSET AND ALLOWS FOR ONLY GRADIENT PORTION TO CONTINUE. TEMPS WILL FALL OVERNIGHT INTO THE MID TO UPPER 20S NORTHWEST TO THE MID 30S FAR SOUTHEAST. FOR THE MOST PART...SENSIBLE WEATHER WILL NOT BE AN ISSUE FOR THE REMAINDER OF THE NIGHT. SHORT TERM CHALLENGES REMAIN FOR AREA RIVERS AND SOME ICE JAMMING...SEE HYDRO DISCUSSION BELOW FOR THAT. .LONG TERM /FRIDAY THROUGH THURSDAY/... AFTER REC TO NEAR REC TEMPS...CDFNT IS MOVG THRU THE CWA AND WILL USHER IN SOMEWHAT COOLER TEMPS. HIGHS FRI EXPECTED TO BE ONLY 10 TO 15 DEGREES ABOVE NORMAL INSTEAD OF 30. SATURDAY WILL BE A TRANSITION DAY BEFORE NEXT SYSTEM MOVES IN. SAT PIX SHOW VERY STRONG SYS MOVG ASHORE THIS AFTN AND WILL AFFECT IA OVR THE WEEKEND. RADICAL CHANGE FROM RUN TO RUN WITH SFC TEMPS NEARLY 30 DEG WARMER ON 12Z VS 06Z. GEM MADE A BIG NWD SHIFT AS WELL. THERE WAS A NWD SHIFT IN THE ECMWF...BUT NOT AS MUCH. MADE SOME ADJ TO FCST...BUT DID NOT BUY INTO THE RADICAL SHIFT. THE CHANGES ARE ENUF THAT IT WILL PUT MOST OF THE SNOWFALL WITH THIS SYS TO THE N OF THE CWA. DEEPER MOISTURE WILL BE IN PLACE AND WILL LIKELY SEE HIGHER QPF AND BETTER CHCS OF TSRA AS WELL SAT NGT INTO SUN. MUCAPE RISES TO THE 500 TO 800 J/KG RANGE ON SUN. COLD AIR WILL SETTLE BACK INTO THE CWA BHND THE LOW SUN NGT AND MON WITH PCPN CHNGG BACK TO SNW. DO NOT EXPECT TO SEE A LOT OF ACCUM AGAIN. TEMPS WILL RETURN TO NORMAL FOR THE FIRST PART OF THE WEEK. NEXT SYSTEM IN THE SERIES WILL BEGIN TO AFFECT THE CENTRAL U.S. DURN THE LATER HALF OF NEXT WEEK. && .HYDROLOGY... WARMING HAS SWEPT CLEAN THE SNOWPACK OVER MUCH OF THE AREA THIS AFTERNOON. AREA RIVERS HAVE RESPONDED WITH GENERALLY SLOW RISES WITH SMALLER CREEKS AND STREAMS RESPONDING MORE RAPIDLY OVER SOME PORTIONS OF THE AREA. AN ICE JAM HAS DEVELOPED ALONG THE RACCOON RIVER IN THE DES MOINES METRO AREA AND HAS CAUSED SOME MINOR FLOODING. OTHER AREAS OF CONCERN INCLUDE FORT DODGE THOUGH AT THIS TIME ONLY A SLOW RISE IN THE RIVER HAS OCCURRED THERE AS OF LATE THURSDAY AFTERNOON. RAINFALL OVER THE UPCOMING WEEKEND MAY PUSH RIVER LEVELS HIGHER AND CAUSE MORE ADDITIONAL WITHIN BANK RISES TO OCCUR. && .AVIATION...18/00Z DRY AIRMASS WILL BE MOVING ACROSS IOWA DURING THE FORECAST PERIOD WITH WIDESPREAD VFR CONDITIONS. VISIBILITIES WILL REMAIN UNRESTRICTED DURING THE FORECAST WITH ANY CEILINGS AOA BKN120. WINDS WILL BE GUSTY FROM THE WNW DURING THE FORECAST PERIOD AS LOW PRESSURE PULLS AWAY FROM THE STATE. && .DMX WATCHES/WARNINGS/ADVISORIES...NONE. && SHORT TERM...REV LONG TERM...MS FEB 11 AVIATION...COGIL HYDROLOGY...REV
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE DES MOINES IA 952 PM CST THU FEB 17 2011 IAZ004>007-015>017-023>028-033>039-044>050-057>062-070>075-081>086- 092>097-181200- 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-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- 952 PM CST THU FEB 17 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL IOWA. .DAY ONE...TONIGHT RAPID SNOW MELT ACROSS THE AREA HAS LED TO STREAM AND SMALL CREEK RISES ACROSS SOME PORTIONS OF THE REGION TODAY WITH THE POTENTIAL FOR SOME MINOR FLOODING. IF ANY ICE JAMS DEVELOP...MORE SIGNIFICANT FLOODING COULD BE POSSIBLE. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY A MIXTURE OF SNOW...SLEET AND FREEZING RAIN IS POSSIBLE LATE SATURDAY NIGHT THROUGH SUNDAY. A CHANCE OF ICE ACCRUAL EXIST LATE SATURDAY NIGHT INTO SUNDAY NIGHT GENERALLY SOUTH OF HIGHWAY 3 TO HIGHWAY 20. ICE ACCRUAL WILL EXIST SUNDAY NIGHT SOUTH OF HIGH WAY 20 TO HIGHWAY 92. LIGHT SNOW ACCUMULATIONS ARE EXPECTED BY SUNDAY NIGHT INTO MONDAY. .SPOTTER INFORMATION STATEMENT... ANY REPORTS OF BANKFULL RISES IN AREA STREAMS AND CREEKS AS WELL AS ICE JAMMING AND FLOODING DUE TO ICE JAMS WOULD BE APPRECIATED. CC
The national radar mosaic for the moment the first event began.
7 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, February 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: 277862, 277853, 277860, 277852, 277855, 277857, 277854.