A combination of melting snow and warmer temperatures helped form ice jams in far southwest Iowa around the middle of the month.
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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 OAX wrote it up.
A combination of melting snow and warmer temperatures helped form ice jams in far southwest Iowa around the middle of the month.
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 Omaha, NE wrote its last area forecast discussion before the first event at Feb 17, 2:34 PM CST, 3 hours 26 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 234 PM CST THU FEB 17 2011 .SHORT TERM...TONIGHT THROUGH SUNDAY. MAIN WEATHER CONCERN THROUGH THE PERIOD WILL BE SATURDAY NIGHT AND SUNDAY AS A NEW LOW PRESSURE SYSTEM MOVES ONTO THE CENTRAL PLAINS. MOISTURE ADVECTING NORTHWARD SHOULD LEAD TO AT LEAST ISOLATED SHOWERS BY SATURDAY AFTERNOON WITHIN THE WARM AIR ADVECTION REGIME. A MORE SUBSTANTIAL THREAT FOR RAIN COMES SATURDAY NIGHT AS LOW LEVEL JET STRENGTHENS...COMBINED WITH THE NORTHWARD ADVANCE OF A SURFACE WARM FRONT...AS THE UPPER LEVEL JET APPROACHES FROM THE WEST. LATEST DETERMINISTIC MODELS ARE NOW TRENDING A LITTLE FURTHER WEST...WHICH PUTS MOST OF THE FORECAST AREA SOLIDLY WITHIN THE WARM SECTOR...SUGGESTING A RAIN EVENT SATURDAY NIGHT AND ADJUSTED FORECAST ACCORDINGLY. HOWEVER... IN NORTHEAST NEBRASKA...SURFACE TEMPS COULD DIP TOWARD FREEZING BY SUNDAY MORNING...THUS THERE COULD BE PATCHY FREEZING RAIN NORTHWEST OF A LINE FROM KOLU TO KLCG. DID INCREASE PROBABILITY FOR PRECIP SATURDAY NIGHT AND SUNDAY INTO THE LIKELY CATEGORY...AND ALSO ADDED IN ISOLATED THUNDERSTORMS AS ALL MODELS ALSO INDICATING SOME WEAK INSTABILITY WITH NEGATIVE 850MB LIFTED INDEX VALUES SPREADING THROUGH THE REGION WITHIN THE WARM SECTOR AS WELL. WITH THE SURFACE LOW TAKING A SLIGHTLY MORE WESTERN AND NORTHERN TRACK...THIS PUSHES ANY AXIS OF HEAVIER SNOW POTENTIAL FURTHER NORTH INTO SOUTH DAKOTA AND NORTHWEST IOWA AS WELL. WITH THE SURFACE LOW PULLING OFF TO THE NORTHEAST ON SUNDAY...WE WILL EXPERIENCE COLDER AIR BEGINNING TO FILTER INTO AT LEAST NORTHEAST NEBRASKA...WHICH SHOULD SWITCH ANY LINGERING PRECIPITATION OVER TO SNOW...BUT BY THEN THE BULK OF THE MEASURABLE PRECIP SHOULD BE FURTHER NORTH AND NOT CAUSE SIGNIFICANT PROBLEMS FOR OUR AREA. MEANWHILE...COLDER AIR DOESN'T REALLY ARRIVE ALONG/SOUTH OF THE INTERSTATE UNTIL SUNDAY NIGHT. 70 .LONG TERM...SUNDAY NIGHT THROUGH THURSDAY. PERIOD BEGINS WITH BOTH THE GFS AND EURO SHOWING MUCH COLDER AIR SPILLING BACK INTO THE AREA WITH SOME CHANCE OF LIGHT SNOW SUNDAY NIGHT INTO EARLY MONDAY. COLDER TEMPERATURES LOOK SHORT LIVED AT THIS TIME HOWEVER AS SURFACE HIGH PRESSURE SHIFTS EAST ON TUESDAY WITH RETURN FLOW SETTING UP IN ADVANCE OF THE NEXT WAVE COMING INTO THE PACIFIC NORTHWEST. MORE UNCERTAINTY CREEPS INTO THE FORECAST WEDNESDAY INTO THURSDAY AS MODELS SHOW MORE VARIATION REGARDING NEXT UPPER WAVE COMING INTO THE NORTHWEST AND ASSOCIATED COLD AIR INTRUSION BEHIND THE COLD FRONT. FOR NOW HAVE TRENDED TOWARD HPC GUIDANCE AND THE SLOWER AND WARMER EURO. LOOKS LIKE COLDER AIR WILL MAKE IT BACK INTO THE AREA JUST A MATTER OF WHEN. FOBERT && .HYDROLOGY... AN ICE JAM OCCURRED ALONG THE PLATTE RIVER EARLIER THIS MORNING AND FLOOD WARNINGS WERE ISSUED VALID THROUGH 4 PM FOR SOME MINOR FLOODING NEAR ASHLAND AND CEDAR CREEK. IT APPEARS THAT THE ICE THAT CAUSED THE JAM HAS FLUSHED OUT PUSHING DOWNSTREAM TOWARD THE MISSOURI AND THOSE WARNINGS WILL LIKELY BE ALLOWED TO EXPIRE. ANOTHER ICE JAM ON THE ELKHORN RIVER AT PILGER WAS BEGINNING TO AFFECT THE RIVER BETWEEN PILGER AND WEST POINT. THERE HAVE ALSO BEEN BAD GAGE READINGS AT BOTH SIGHTS AT THE USGS IS ONSITE REPAIRING THOSE AT THE MOMENT. A FLOOD ADVISORY WAS ISSUED FOR THAT STRETCH FOR MINOR RURAL LOWLAND FLOODING ALONG THE RIVER BANKS. WITH CONTINUED WARMTH...HOPEFULLY WE CAN CONTINUE TO FLUSH OUT ICE DOWNSTREAM OVER THE NEXT COUPLE OF DAYS. ADDITIONAL RAINFALL EXPECTED THIS WEEKEND IS SLIGHTLY CONCERNING. AT THIS TIME...RAINFALL AMOUNTS LESS THAN ONE HALF INCH ARE FORECAST. NOT SURE THIS WILL BE ENOUGH TO CAUSE ANY ADDITIONAL WIDESPREAD PROBLEMS. WITHIN BANK RISES ARE ALSO FORECAST ALONG THE NISHNABOTNA RIVER IN SOUTHWEST IOWA. 70 && .FIRE WEATHER... SURFACE DEWPOINTS HAVE MIXED DOWN INTO THE UPPER TEENS ACROSS NORTH CENTRAL AND NORTHEAST NEBRASKA THIS AFTERNOON. THIS HAS RESULTED IN RELATIVE HUMIDITY VALUES DROPPING TO AROUND OR JUST BELOW 20 PERCENT. WITH GUSTY NORTHWEST WINDS...THERE IS A VERY HIGH TO EXTREME FIRE DANGER THERE THIS AFTERNOON...HOWEVER FUELS MAY STILL BE SLIGHTLY WET FROM RECENT SNOW AND CONDITIONS SHOULD IMPROVE TOWARD SUNSET. 70 && .AVIATION... TAF SITES KOFK/KOMA/KLNK 18Z TAFS VFR CONDITIONS WILL PREVAIL THROUGH THE FORECAST PERIOD. FRONTAL PASSAGE/WIND SHIFT TO THE NORTHWEST HAS ALREADY OCCURRED AT KOFK. AT KOMA AND KLNK WIND SHIFT TO NORTHWEST AROUND 21Z THIS AFTERNOON WITH GUSTS AROUND 25KT EXPECTED UNTIL 18/00Z. DEE && .OAX WATCHES/WARNINGS/ADVISORIES... NE...NONE. IA...NONE. &&
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE OMAHA/VALLEY NE 434 PM CST THU FEB 17 2011 IAZ069-079-080-090-091-NEZ011-016-017-030>033-042>044-050>053-067- 068-181245- POTTAWATTAMIE-MILLS-MONTGOMERY-FREMONT-PAGE-KNOX-ANTELOPE-PIERCE- BOONE-MADISON-STANTON-CUMING-PLATTE-COLFAX-DODGE-BUTLER-SAUNDERS- DOUGLAS-SARPY-CASS-OTOE- 434 PM CST THU FEB 17 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST IOWA...EAST CENTRAL NEBRASKA...NORTHEAST NEBRASKA AND SOUTHEAST NEBRASKA. .DAY ONE...TONIGHT AND FRIDAY AREA RIVERS AND STREAMS WILL CONTINUE TO BE MONITORED FOR POSSIBLE MINOR FLOODING AND ICE JAMS. THE MAIN THREATS APPEAR TO BE ALONG THE ELKHORN RIVER FROM PILGER TO ARLINGTON. BUT THE PLATTE RIVER ABOVE ASHLAND...AND THE NISHNABOTNA RIVER IN WESTERN IOWA WILL ALSO NEED TO BE WATCHED. .DAYS TWO THROUGH SEVEN...FRIDAY NIGHT THROUGH THURSDAY A WEATHER SYSTEM MOVING ONTO THE PLAINS COULD BRING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TO THE AREA SATURDAY NIGHT...AND POSSIBLY MIXED WITH FREEZING RAIN ACROSS NORTHEAST NEBRASKA BY SUNDAY MORNING. AS COLDER AIR FILTERS INTO THE SYSTEM...THIS COULD CHANGE THE RAIN OVER TO SNOW ON SUNDAY AND SUNDAY NIGHT...ALTHOUGH SIGNIFICANT AMOUNTS OF SNOW ARE NOT EXPECTED. .SPOTTER INFORMATION STATEMENT... SPOTTERS WILL NOT BE NEEDED TONIGHT OR FRIDAY. IAZ043-055-056-NEZ012-015-018-034-045-181245- MONONA-HARRISON-SHELBY-CEDAR-THURSTON-WAYNE-BURT-WASHINGTON- 434 PM CST THU FEB 17 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHWEST IOWA...WEST CENTRAL IOWA...EAST CENTRAL NEBRASKA AND NORTHEAST NEBRASKA. .DAY ONE...TONIGHT AND FRIDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...FRIDAY NIGHT THROUGH THURSDAY A WEATHER SYSTEM MOVING ONTO THE PLAINS COULD BRING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TO THE AREA SATURDAY NIGHT...AND POSSIBLY MIXED WITH FREEZING RAIN ACROSS NORTHEAST NEBRASKA BY SUNDAY MORNING. AS COLDER AIR FILTERS INTO THE SYSTEM...THIS COULD CHANGE THE RAIN OVER TO SNOW ON SUNDAY AND SUNDAY NIGHT...ALTHOUGH SIGNIFICANT AMOUNTS OF SNOW ARE NOT EXPECTED. .SPOTTER INFORMATION STATEMENT... SPOTTERS WILL NOT BE NEEDED TONIGHT OR FRIDAY. NEZ065-066-078-088>093-181245- SEWARD-LANCASTER-SALINE-JEFFERSON-GAGE-JOHNSON-NEMAHA-PAWNEE- RICHARDSON- 434 PM CST THU FEB 17 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF SOUTHEAST NEBRASKA. .DAY ONE...TONIGHT AND FRIDAY THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...FRIDAY NIGHT THROUGH THURSDAY A WEATHER SYSTEM MOVING ONTO THE PLAINS COULD BRING SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS TO THE AREA SATURDAY NIGHT. AS COLDER AIR FILTERS INTO THE SYSTEM...THIS COULD CHANGE THE RAIN OVER TO SNOW BY SUNDAY...ALTHOUGH SIGNIFICANT AMOUNTS OF SNOW ARE NOT EXPECTED. .SPOTTER INFORMATION STATEMENT... SPOTTERS WILL NOT BE NEEDED TONIGHT OR FRIDAY.
The national radar mosaic for the moment the first event began.
1 flood. Local standard time, as filed.
Ice jam flooding was observed along the East Nishnabotna River which crossed County Road J46 near Riverton. Damage was apparently minimal.
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: 277562.