Heavy Snow, Cass
- When
- January 9, 9:00 PM CST to January 10, 6:00 PM CST
- Where
- Cass forecast zone
- Reported by
- Trained Spotter
- Coordinates
- 41.332, -94.928 (the zone’s center; the record gives no point)
Snowfall of 8.1 inches was reported.
Heavy Snow in Iowa, January 9 to 10, 2011
A large upper level trough was situated over the northern Rockies with an embedded shortwave trough ejecting northeastward toward Iowa on the 9th into the 10th. Southerly flow aloft sent moisture and warm air northward with light snow spreading across the western portion of Iowa on Monday the 9th.
Where it happened
Every event with a place to put it; 1 filed by county or forecast zone are drawn at its center, in a lighter ring. 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
The toll
- Deaths
- 0
- Injuries
- 0
- Property damage
- None recorded
- Crop damage
- None recorded
- Events
- 1
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 DMX wrote it up.
A large upper level trough was situated over the northern Rockies with an embedded shortwave trough ejecting northeastward toward Iowa on the 9th into the 10th. Southerly flow aloft sent moisture and warm air northward with light snow spreading across the western portion of Iowa on Monday the 9th. The snow picked up in intensity and spread across much of the state during the overnight hours into the 10th and continued snowing through much of the day. The snow was mainly light with many sites across west central Iowa picking up 8 to 10 inches over the course of 48 hours. However two slightly more intense bands of snow moved through Cass County in southwest Iowa during the early morning hours of the 10th that allowed Cumberland to pick up 8.1 inches of snow in 24 hours or less.
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 Des Moines, IA wrote its last area forecast discussion before the first event at Jan 9, 5:47 PM CST, 3 hours 13 minutes earlier.
Area forecast discussion, Jan 9, 5:47 PM CST, 3 hours 13 minutes before
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE DES MOINES IA 547 PM CST SUN JAN 9 2011 .SHORT TERM /TONIGHT/... SNOW CURRENTLY ONGOING OVER WEST CENTRAL AND SOUTHWEST IOWA ALONG THE LEADING EDGE OF THETA-E ADVECTION. DRY AIR TO THE EAST IS LIMITING THE ADVANCEMENT EASTWARD. ANOTHER ROUND OF DRY AIR AROUND 850 MB WILL LIFT NORTH OUT OF NORTHEAST MISSOURI...MAINLY ALONG AND EAST OF INTERSTATE 35 AND SHOULD LIMIT SNOW POTENTIAL TO THE EAST OF THIS REGION. SNOW IS EXPECTED WEST OF INTERSTATE 35 WHERE THE DEEPEST SATURATION OCCURS. THERMODYNAMIC FORCING WILL CONTINUE THROUGHOUT THE NIGHT. THOUGH THE FORCING IS MODEST WITH IN THE DENDRITIC LAYER...THE DENDRITIC LAYER ITSELF IS QUITE DEEP...EXTENDING FROM NEAR SFC TO AROUND 15 KFT. THIS SHOULD RESULT IN A GOOD QUANTITY OF DENDRITES. THAT SAID THOUGH...THE MAJORITY OF FORCING IS OCCURRING AT OR ABOVE 500 MB WHERE TEMPERATURES WILL AVERAGE -32C. THESE CONDITIONS WILL PROMOTE COLUMN AND SMALL PLATE GROWTH AND WILL HAVE SOME NEGATIVE IMPACT ON SNOW RATIOS. OVERALL...SNOW RATIOS SHOULD BE NEAR 15 TO 1 WITH AMOUNTS BY 6 AM MONDAY RANGING FROM 2 TO 4 INCHES FAR WEST AND NORTHWEST...1 TO 2 NEAR INTERSTATE 35 AND NO ACCUMS FAR EAST. SPLIT THE START TIMES FOR THE WINTER ADVISORIES TONIGHT...STARTING AT ISSUANCE TIME OVER THE FAR WEST AND AT 06Z CENTRAL. READ BELOW OR MOVE INFORMATION REGARDING THE HEADLINES. .LONG TERM /MONDAY THROUGH SUNDAY/... MODELS COMING INTO BETTER CONSENSUS WITH INVERTED TROUGH LONG DURATION SNOW EVENT IN THE NEXT 48 HOURS. UPGLIDE WITH ISENTROPIC LIFT HAS ALREADY BEGUN TODAY AND WILL TRACK EAST IN THE NEXT 24 HOURS. TIME HT CROSS SECTIONS SHOW THAT THE BEST LIFT WILL OCCUR OVER WESTERN IOWA THROUGH ABOUT 18Z MON AND THROUGH CENTRAL IA THROUGH ABOUT 00Z FROM THE TROUGH ITSELF AS IT PIVOTS TO THE NORTHEAST WITH TIME. AT THE SAME TIME AN UPPER LEVEL SHORT WAVE WILL ENHANCE THE PRECIP MONDAY EVENING AND OVERNIGHT AS QG FORCING INCREASES FROM THAT FEATURE. THIS ALSO INDUCES A WEAK SFC FEATURE TO OUR SOUTHEAST HELPING TO CREATE A DEFORMATION ZONE ACROSS THE CENTRAL AND EAST THROUGH EARLY TUESDAY. THE SOUTHWEST/WEST CENTRAL LOOK TO BE IN THE BEST DENDRITIC LIFT THE SEE THE LONGEST DURATION AS WELL... AND CONCEIVABLY MIGHT SEE CLOSER TO 10 INCHES BY THE TIME THE SYSTEM DEPARTS WITH LESSER TOTALS OF 5 TO 8 FROM EAST BACK TOWARD CENTRAL SECTIONS. BECAUSE THE EVENT CONTINUES TO BE LONG DURATION...SNOWFALL AMTS FOR A GIVEN PERIOD SHOULD REMAIN SHY OF WARNING CRITERIA...6 INCHES/12 HOURS OR 8 INCHES/24 HOURS. WILL BE STICKING TO AN ADV FOR NOW AND KEEP AN EYE ON MONDAY RATES SOUTHWEST. THE BIGGER ISSUE FROM THIS EVENT SHOULD OCCUR TUESDAY FROM WEST TO EAST. AS THE TROUGH BEGINS TO DEPART HIGH PRESSURE DROPPING SOUTHEAST INTO THE PLAINS WILL STRENGTHEN THE SFC PRESSURE GRADIENT AND RESULT IN WINDS OF 12 TO 20 MPH AMBIENT WITH GUSTS TO NEAR 25 MPH AT TIMES THROUGH 06Z. THIS WILL RESULT IN A FAIR AMOUNT OF GROUND BLOWING AND DRIFTING FOR 12 TO 18 HOURS. THIS WILL PROBABLY REQUIRE A SEPARATE SET OF HEADLINES OR EXTENSION FOR SOME AREAS AS BLOWING SNOW MAY BECOME AN ISSUE AT THIS TIME. SO...DESPITE THE CURRENT ADVISORY ONLY COVERING CENTRAL AREAS...MAY SEE HEADLINES EAST AS WELL FOR LATE TOMORROW AND TUESDAY. GIVEN THE COLDER TEMPERATURES WITH THIS SNOWFALL...THE DRIER SNOW WILL BLOW MORE EASILY ACROSS ROADS AND FIELDS. BY WED THE WINDS WILL RELAX AS THE HIGH BEGINS TO MOVE INTO THE REGION. THERE ARE STILL SOME QUESTIONS AS TO THE AMOUNT OF SUN TO RETURN TO THE AREA WED AS AN UPPER LEVEL TROUGH SWINGS ACROSS THE AREA. THIS MAY KEEP HIGHS RATHER COLD AND ALLOW LOWS TO DROP SIGNIFICANTLY FOR WED NIGHT/THURSDAY MORNING. MENS GUIDANCE QUITE LOW FOR THE MORNING HOURS THURSDAY WITH MILDER AIR APPROACHING AS A LATE WEEK WAVE SWINGS INTO THE AREA. ANOTHER CHANCE FOR SNOW WILL OCCUR ON FRIDAY...ESPECIALLY NORTH WITH SOME POTENTIAL FOR ACCUMULATION. MED RANGE MODELS AT ODDS WITH EXTENT OF COLD AIR FOR THE UPCOMING WEEKEND. GFS BRINGS ARCTIC ONSLAUGHT TO REGION BY SATURDAY WHILE THE EURO/GEM KEEP COLDEST AIR NORTH OF THE REGION AND BRING A LESS INTENSE SHOT OF COLD TO THE AREA. FOR NOW HAVE TRIED TAKEN A MIDDLE OF THE ROAD APPROACH...THOUGH EVEN WITH THAT POTENTIAL SUN MORNING APPROACHING 10 BELOW NORTH. STILL PLENTY OF TIME TO MAKE ADJUSTMENTS. CERTAINLY A LOT OF DETAILS TO SORT THROUGH IN THE COMING DAYS. && .AVIATION...10/00Z SNOW WAS JUST BEGINNING TO AFFECT KFOD AND BIG QUESTION FOR THIS PERIOD WILL BE ITS EASTWARD PROGRESSION. THERE IS PERSISTENT DRY AIR TO OVERCOME AND HAVE PROLONGED ONSET A BIT MORE AT KOTM AS PER SUGGESTION OF RECENT MODEL RUNS. WITH PERIOD NOW EXTENDING BEYOND 18Z...FURTHER INTO TIMING OF HEAVIER SNOW...HAVE LOWERED WORST CONDITIONS TO LIFR VSBYS WITH SNOW CONTINUING INTO THE EVENING. && .DMX WATCHES/WARNINGS/ADVISORIES... WINTER WEATHER ADVISORY FROM MIDNIGHT TO 6 AM TUESDAY BOONE-CLARKE-DALLAS-DECATUR-HAMILTON-HANCOCK-LUCAS-MADISON-POLK- RINGGOLD-STORY-TAYLOR-UNION-WARREN-WAYNE-WINNEBAGO-WRIGHT. WINTER WEATHER ADVISORY UNTIL 6 AM CST TUESDAY FOR ADAIR-ADAMS- AUDUBON-CALHOUN-CARROLL-CASS-CRAWFORD-EMMET-GREENE-GUTHRIE- HUMBOLDT-KOSSUTH-PALO ALTO-POCAHONTAS-SAC-WEBSTER. && SHORT TERM...DONAVON LONG TERM...REV AVIATION...SMALL
Hazardous weather outlook, Jan 9, 4:41 PM CST, 4 hours 19 minutes before
HAZARDOUS WEATHER OUTLOOK...CORRECTION FOR WORDING 1ST SEGMENT NATIONAL WEATHER SERVICE DES MOINES IA 441 PM CST SUN JAN 9 2011 IAZ004>006-015-016-023>025-033>036-044>048-057>060-070>073-081>084- 092>095-102130- EMMET-KOSSUTH-WINNEBAGO-PALO ALTO-HANCOCK-POCAHONTAS-HUMBOLDT-WRIGHT- SAC-CALHOUN-WEBSTER-HAMILTON-CRAWFORD-CARROLL-GREENE-BOONE-STORY- AUDUBON-GUTHRIE-DALLAS-POLK-CASS-ADAIR-MADISON-WARREN-ADAMS-UNION- CLARKE-LUCAS-TAYLOR-RINGGOLD-DECATUR-WAYNE- 441 PM CST SUN JAN 9 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND WESTERN IOWA. .DAY ONE...TONIGHT LIGHT SNOW WILL INCREASE LATE TONIGHT WITH MODERATE SNOWFALL BY EARLY MONDAY MORNING WEST OF HIGHWAY 169. LIGHT SNOWFALL AMOUNTS WILL OCCUR AS FAR EAST AS INTERSTATE 35 BY EARLY MONDAY. A WINTER WEATHER ADVISORY IS IN EFFECT FOR THE AREA. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY A LONG DURATION SNOWFALL EVENT WILL CONTINUE THROUGH LATE TUESDAY. MODERATE TO LOCALLY HEAVY STORM TOTAL ACCUMULATIONS ARE EXPECTED WITH THE MOST INTENSE SNOWFALL RATES OCCURRING MONDAY INTO MONDAY NIGHT. WINDS WILL INCREASE ON TUESDAY TO AROUND 15 TO 25 MPH CREATING SOME BLOWING AND DRIFTING SNOW. A WINTER WEATHER ADVISORY IS IN EFFECT FOR THE AREA. PLEASE REFER TO THE NATIONAL WEATHER SERVICE WEBSITE AT WEATHER.GOV/DESMOINES FOR FURTHER DETAILS. ANOTHER CHANCE FOR ACCUMULATING SNOW WILL OCCUR FRIDAY AND OVER THE WEEKEND WITH SOME ACCUMULATIONS POSSIBLE. BITTER COLD TEMPERATURES AND DANGEROUS WIND CHILLS WILL BE POSSIBLE THURSDAY MORNING AND AGAIN LATE IN THE WEEKEND. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED...HOWEVER SNOWFALL REPORTS AND UPDATES DURING THE UPCOMING EVENT ARE ENCOURAGED. IAZ007-017-026>028-037>039-049-050-061-062-074-075-085-086-096-097- 102130- WORTH-CERRO GORDO-FRANKLIN-BUTLER-BREMER-HARDIN-GRUNDY-BLACK HAWK- MARSHALL-TAMA-JASPER-POWESHIEK-MARION-MAHASKA-MONROE-WAPELLO- APPANOOSE-DAVIS- 441 PM CST SUN JAN 9 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR PORTIONS OF CENTRAL AND EASTERN IOWA. .DAY ONE...TONIGHT NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...MONDAY THROUGH SATURDAY A LONG DURATION SNOWFALL EVENT WILL BEGIN MONDAY MORNING AND CONTINUE THROUGH LATE TUESDAY. MODERATE STORM TOTAL ACCUMULATIONS ARE EXPECTED WITH THE MOST INTENSE SNOWFALL RATES OCCURRING MONDAY AFTERNOON INTO MONDAY NIGHT. WINDS WILL INCREASE ON TUESDAY TO AROUND 15 TO 25 MPH CREATING SOME BLOWING AND DRIFTING SNOW. ANOTHER CHANCE FOR ACCUMULATING SNOW WILL OCCUR FRIDAY AND OVER THE WEEKEND WITH SOME ACCUMULATIONS POSSIBLE. BITTER COLD TEMPERATURES AND DANGEROUS WIND CHILLS WILL BE POSSIBLE THURSDAY MORNING AND AGAIN LATE IN THE WEEKEND. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED...HOWEVER SNOWFALL REPORTS AND UPDATES DURING THE UPCOMING EVENT ARE ENCOURAGED. REV/BSS
In the hours before
Local storm report, Jan 9, 6:48 PM CST, 2 hours 12 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
648 PM CST SUN JAN 09 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0640 PM SNOW 1 W CUMBERLAND 41.27N 94.89W
01/09/2011 M1.5 INCH CASS IA TRAINED SPOTTER
&&
RHATTEBELocal storm report, Jan 9, 8:37 PM CST, 23 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
837 PM CST SUN JAN 09 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0800 PM SNOW DENISON 42.02N 95.35W
01/09/2011 E3.0 INCH CRAWFORD IA LAW ENFORCEMENT
0805 PM SNOW DELOIT 42.10N 95.32W
01/09/2011 E2.0 INCH CRAWFORD IA CO-OP OBSERVER
0809 PM SNOW SAC CITY 42.42N 95.00W
01/09/2011 M1.0 INCH SAC IA CO-OP OBSERVER
0812 PM SNOW CARROLL 42.07N 94.86W
01/09/2011 E1.0 INCH CARROLL IA LAW ENFORCEMENT
0815 PM SNOW CRESTON 41.06N 94.36W
01/09/2011 E1.5 INCH UNION IA LAW ENFORCEMENT
0817 PM SNOW BEDFORD 40.67N 94.72W
01/09/2011 E1.5 INCH TAYLOR IA CO-OP OBSERVER
&&
RHATTEBELocal storm report, Jan 9, 8:48 PM CST, 12 minutes before
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE DES MOINES IA
848 PM CST SUN JAN 09 2011
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0840 PM SNOW AUDUBON 41.72N 94.93W
01/09/2011 E2.0 INCH AUDUBON IA LAW ENFORCEMENT
0845 PM SNOW LEWIS 41.31N 95.08W
01/09/2011 E2.0 INCH CASS IA CO-OP OBSERVER
&&
RHATTEBEThe radar
The national radar mosaic for the moment the first event began.
Event by event
1 heavy snow. Local standard time, as filed.
What these are
- Heavy Snow
- Snowfall reaching the local warning threshold without the other hazards of a winter storm.
After NWS Directive 10-1605, the rules offices file Storm Data by.
The same day elsewhere
- Ice Storm and Winter Storm in Alabama, January 9 to 10, 2011
- Winter Storm and Winter Weather in Kansas, January 9 to 10, 2011
- Winter Storm in Louisiana, January 9, 2011
- Ice Storm and Winter Storm in Georgia, January 9 to 14, 2011
- Heavy Snow in Texas, January 9, 2011
- Winter Storm and Winter Weather in Nebraska, January 9 to 12, 2011
- Tornadoes and Hail in Texas, January 9, 2011
- Heavy Snow and Winter Weather in South Dakota, January 9 to 10, 2011
- Winter Storm in Mississippi, January 9 to 10, 2011
- Ice Storm and Heavy Snow in Mississippi, January 9, 2011
- Heavy Snow in Arkansas, January 9, 2011
- Ice Storm and Winter Weather in Louisiana, January 9, 2011
More
Every storm in Iowa in 2011Every state in 2011This day in weather historyWarnings in Iowa, January 2011
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: 287799.