Winter Storm in Iowa, March 11 to 12, 2001

Name: Winter Storm in Iowa, March 11 to 12, 2001
Start: 2001-03-11T23:00
End: 2001-03-12T13:45
Location: Iowa

March 11 to 12, 2001 · NWS ARX · 1 event in 1 county or zone

The last significant snowfall of the season affected northeast Iowa, with the heaviest amounts near the Iowa-Minnesota border. A volunteer weather observer reported 6 inches of accumulation at Dorchester (Allamakee County).

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

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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 ARX wrote it up.

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 La Crosse, WI wrote its last area forecast discussion before the first event at Mar 11, 3:15 PM CST, 7 hours 45 minutes earlier.

Area forecast discussion, Mar 11, 3:15 PM CST, 7 hours 45 minutes before

AREA FORECAST DISCUSSION
NATIONAL WEATHER SERVICE LA CROSSE WI
315 PM CST SUN MAR 11 2001

MAIN FORECAST CONCERN IS THE WINTER STORM FOR MONDAY AND MONDAY
NIGHT. HOW MUCH PCPN AND WHAT TYPES?

12Z MODEL INITIALIZATION GENERALLY LOOKS GOOD. LOOKS TO BE TOO
STRONG WITH THE NORTHERN 300 MB JET...AND PERHAPS A BIT TOO WEAK
WITH THE SOUTHERN REACH OF THE SOUTHERN BRANCH. MODELS ARE MORE
COMPARABLE THIS GO AROUND...WITH POSITIONING ON THE MAJOR FEATURES
VERY SIMILAR TO EACH OTHER. THE ETA IS A BIT STRONGER...AND A TAD
SLOWER. DON/T THINK THIS SHOULD CAUSE A BIG IMPACT TO THE SENSIBLE
WEATHER THOUGH. OF BIGGER SIGNIFICANCE IS THE WARMER SOLUTION OF THE
ETA. THIS WOULD BRING MORE FREEZING TYPE PCPN TO THE
REGION...CUTTING SHORT A LONG PERIOD OF SNOW THAT THE AVN WOULD
TREND TOWARD. THE LAST SEVERAL STORMS HAVE PULLED THE WARM AIR NORTH
THOUGH...WHICH SUPPORTS THE ETA. TOUGH TO PICK ONE OR THE OTHER AT
THE MOMENT...AND WILL HAVE TO GO WITH A BLEND FOR NOW.

THE CLOSED 500 MB LOW AND ACCOMPANYING SHORTWAVE WILL LIFT OVER THE
CENTRAL PLAINS BY 06Z TONIGHT...WITH THE LOW FILLING AS THE TROUGH
AXIS SWINGS OVER WI FOR MONDAY NIGHT. THE BULK OF THE SHORTWAVE
ENERGY WILL STAY JUST SOUTH...ACROSS IOWA AND NORTHERN ILL.
CYCLOGENESIS GETS GOING IN EARNEST LATE TONIGHT...WITH THE
STRENGTHENING SFC LOW MOVING INTO EASTERN IA BY 18Z MON AND OVER
EASTERN WI BY 06Z TUES. TIGHT 850 MB TEMP GRADIENT CAN BE EXPECTED
FOR MON...WITH THE NOSE OF THE LOW LEVEL JET EDGING INTO SOUTHERN WI
BY 12Z MON. WOULD EXPECT A GOOD DEFORMATION AREA TO SET UP ACROSS
PARTS OF THE AREA. STRONG QG CONVERGENCE ACCOMPANIES THIS
DEVELOPING STORM...WITH THE STRONGEST LIFT LIKELY FROM 12-20Z MON.
IN ADDITION...A-GEOSTROPHIC MOTIONS FROM THE UPPER LEVEL JETS IMPLY
ADDITIONAL LIFT FOR THE REGION. MOISTURE WILL NOT BE A
PROBLEM...WITH GOOD 850 MB MOISTURE TRANSPORT AND SFC PW/S FROM 0.6
TO 0.8 INCHES. ISENTROPIC UPGLIDE IS ALSO EVIDENT. SO...THE QUESTION
REMAINS NOT IF THERE WILL BE PRECIPITATION...BUT RATHER THE TYPE AND
HOW MUCH.

AT 850 MB...THE 0 DEGREE ISOTHERM PUSHES NORTH TO A RST-LSE LINE BY
12Z MON...CONTINUING ALL THE WAY TO NORTH OF AN EAU-AUW LINE BY 18Z.
THE FORECAST AREA THEN DROPS BACK BELOW ZERO AT 850 MB BY 00Z
TUES...AS THE 850 LOW MOVES EAST. SITUATION IS MORE COMPLEX THEN 850
MB TEMPS THOUGH. LOOKING AT THE FORECAST SOUNDINGS...FOR PDU
(SOUTHWEST WI)...A WARM LAYER MOVES IN BETWEEN 900-850 MB...POINTING
TOWARD A SLEET TO FREEZING RAIN MIX. SURFACE TEMPS LOOK TO WARM
ABOVE FREEZING BY NOON...WHICH SHOULD KEEP ALL THE PCPN AS RAIN FOR
THAT AREA. FOR NORTHEAST IA...THE WARMING ISN/T AS GREAT...WITH
SOUNDINGS INDICATING SOME SLEET CHANCES FOR MON MORNING. GENERALLY
THOUGH...SNOW LOOKS TO BE THE MAIN PCPN TYPE. FOR POINTS NORTH...IN
THE RST AND LSE AREAS...VERTICAL PROFILES POINT TO SNOW...WITH
PERHAPS SOME SMALL INDICATIONS OF A MIX AT TIMES. HOWEVER...FROM LSE
TO THE EAST SFC TEMPS SHOULD WARM TO ABOVE FREEZING...WHICH LEADS TO
MORE RAIN THEN. WITH ALL THIS IN MIND...FEEL THE BEST SNOW
CHANCES...AND ACCUMULATING SNOWS...WILL FALL FROM AROUND AN AUSTIN
MN TO BLACK RIVER FALLS WI LINE AND NORTH. MORE OF A THREAT FOR SOME
ICING WITH THE SNOW SOUTH OF THERE...AND THEN MOSTLY RAIN FOR
EXTREME NORTHEAST IA AND SOUTHWEST WI. OBVIOUSLY...ALL THIS COULD
CHANGE BASED ON JUST HOW MUCH AND HOW FAST THE WARM AIR IS ENTRAINED
INTO THE SYSTEM...AND ACROSS THE FORECAST AREA.

WITH ALL THIS IN MIND...WILL ISSUE A WINTER STORM WARNING FOR THOSE
AREAS WHERE SNOW WILL BE THE DOMINATE PCPN TYPE...AND A WINTER
WEATHER ADVISORY SOUTH OF THERE. FOR NOW...WILL LEAVE THE EXTREME
NORTHEAST IA/SOUTHWEST WI CUT CLEAR OF ANY HEADLINES. CURRENTLY
DON/T EXPECT THE PERIOD OF MIXED WINTER PCPN TO CAUSE TOO MANY
PROBLEMS BEFORE CHANGING OVER TO RAIN LATE MONDAY MORNING.

COORDINATED WITH MPX...GRB...MKX...DMX...DVN.

.LSE...WINTER STORM WARNING...LATE TONIGHT AND MONDAY...
       MNZ079-086>088-094-095-
       WINTER STORM WARNING...MONDAY AND MONDAY NIGHT...
       WIZ017-029-032>034-
       WINTER WEATHER ADVISORY...LATE TONIGHT AND MONDAY...
       IAZ008>010-018-019-029-
       WINTER WEATHER ADVISORY...MONDAY AND MONDAY NIGHT...
       IAZ011-MNZ096-WIZ041>044-053.

RIECK

The radar

The national radar mosaic for the moment the first event began.

Open the radar archive at this moment

Event by event

1 winter storm. Local standard time, as filed.

Winter Storm, Allamakee

When: March 11, 11:00 PM CST to March 12, 1:45 PM CST
Where: Allamakee forecast zone
Reported by: GENERAL PUBLIC
Coordinates: 43.284, -91.378 (the zone’s center; the record gives no point)

What these are

Winter Storm: A storm that brought snow, sleet or freezing rain at warning levels, usually over several hours or days.

After NWS Directive 10-1605, the rules offices file Storm Data by.

The same day elsewhere

Every storm in Iowa in 2001 Every state in 2001 This day in weather history Warnings in Iowa, March 2001

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: 5233893.