A very strong cold front was accompanied by a narrow band of moderate to heavy snowfall, as well as wind gusting to 30 to 45 mph. Most areas saw a brief period of rain, freezing rain or sleet before changing to snow, which was accompanied by a temperature fall of 10 to 20 degrees over a six hour period.
Every event with a place to put it; 11 filed by county or forecast zone are drawn at its center, in a lighter ring. 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 FSD wrote it up.
A very strong cold front was accompanied by a narrow band of moderate to heavy snowfall, as well as wind gusting to 30 to 45 mph. Most areas saw a brief period of rain, freezing rain or sleet before changing to snow, which was accompanied by a temperature fall of 10 to 20 degrees over a six hour period. Contraction of the band occurred due to strong elevated instability, with isolated thunder occurring in southeast South Dakota and southwest Minnesota. While most areas received around an inch or two of snowfall, the band peaked in intensity around the Sioux Falls area with up to three to five inches.
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 Sioux Falls, SD wrote its last area forecast discussion before the first event at Feb 3, 10:51 PM CST, 1 hour 9 minutes earlier.
AREA FORECAST DISCUSSION...UPDATED
National Weather Service Sioux Falls SD
1051 PM CST Wed Feb 3 2021
.UPDATE...
Issued at 1050 PM CST Wed Feb 3 2021
Scattered rain, snow, and wintry mix continues across southwest
MN and southeast SD late this evening. Rain transitioned to snow
pretty quickly at FSD and areas west of I-29, though some sites
likely did see a brief period of freezing drizzle. Precipitation
will spread into northwest IA and far northeast NE over the next
few hours, with snow being the dominant ptype.
Be prepared for slick roads overnight through early Thursday, as
wet roads may flash freeze as the temperature drops into the 20s
and eventually teens.
&&
.SHORT TERM...(This Evening through Thursday)
Issued at 343 PM CST Wed Feb 3 2021
Those who saw sunshine and warm temperatures today should take a
few minutes this evening to enjoy it, as our mild weather will
soon become a warm memory due to a pattern change for at least the
next week. We've warmed into the 30s for most, with upper 30s and
lower 40s for those enjoying the sunshine.
Clouds increase again this evening ahead of a surface cold front and
upper wave progged to move through the Northern Plains tonight
through Thursday. A mixed bag of precipitation is expected as the
front progresses (see subsequent paragraphs). Temperatures will fall
tonight and continue to fall or remain steady through Thursday.
Expect temps in the teens and 20s. Southerly winds, breezy at times
today, will shift northwesterly. These winds strengthen with the
support of CAA, a tight pressure gradient, and strong flow through
the mixed layer. Expect sustained winds around 25mph with gusts up
to 40mph. Can't rule out some higher gusts, if some of the more mixy
models win out.
QPF values have come in lower overall today, with much more model
agreement than previous days. 03/12z deterministic runs of the GFS,
NAM, and EC align fairly well with less than a third of an inch of
QPF in our southeast, and lesser amounts moving northwest. The
Canadian, however, shows two bands of 0.20" to 0.30" QPF - one
across our southeastern counties and the other across south central
into eastern SD. Deterministic snowfall amounts have also decreased
from previous runs, with general agreement of 2" or less. All that
said, have lowered our current forecast amounts slightly, with less
than a quarter inch of liquid and 2 inches or less of snow (highest
for both values in northwestern IA/southwestern MN). Confidence is
higher than average in amounts at this time, given that both
deterministic and probabilistic snowfall amounts have decreased.
That said, p-type issues remain a trick and potential spoiler to
amounts. Model soundings hint at a brief warm nose with temperatures
just above freezing aloft and near/below freezing at the surface to
create some freezing rain or sleet. Still some questions in
timing/location of this, as it will be highly dependent on how
quickly the surface temperatures fall behind the front, and how
quickly saturation occurs. Not expecting any ice accumulations,
other than potentially a light glaze.
Despite the lower-than-previous-forecast snowfall totals, still
expect some hazardous impacts across the area. The first is the
flash freeze potential. Area of greatest concern remains across
northeastern NE/northwestern IA and portions of southwestern MN
where sunshine aided in warming today and temperatures are likely to
remain warm enough for rain ahead of the front. The second impact is
blowing snow with the gusty winds, again most likely to impact
northeastern NE/northwestern IA/southwestern MN. Although the
highest winds will be behind the falling snow, still expect some
blowing snow through Thursday. Have left the Winter Weather Advisory
in place for our southeastern counties for late tonight into midday
Thursday.
.LONG TERM...(Thursday Night through Wednesday)
Issued at 343 PM CST Wed Feb 3 2021
Thursday night starts the Arctic Blast of temperatures. Some of the
warmest lows of the extended expected on Thursday night, in the
single digits and teens. Overall, synoptic scale pattern shows upper
low and mid level low pressure spinning over south central Canada.
ejecting multiple short waves and vorticity lobes through the base of
the trough into early next week. This leads to occasional light snow
chances, additional pushes of CAA, and continued northwesterly flow.
Ensemble guidance is pessimistic with our chances of seeing temps
above freezing through the extended and beyond. For example, the
latest GEFS plumes for our area do not have a single ensemble member
with 2m temps above freezing for at least the next week.
Additionally, deterministic models show 925mb temperatures -15 deg C
or below for much of the extended. Left the NBM in place through the
extended, as it falls near/below the 25th percentile of available
guidance. As temperatures plummet, any winds could create hazardous
wind chills in the teens and potentially twenties below. Anyone who
plans on spending time outdoors this weekend and early next week
will want to take precautions to limit exposure and prevent cold
related illnesses.
&&
.AVIATION...(For the 06Z TAFS through 06Z Thursday night)
Issued at 1050 PM CST Wed Feb 3 2021
IFR to low IFR will prevail overnight as scattered rain and snow
track in behind a cold front. As the temperature falls and winds
increase behind the front, rain will change to freezing rain/sleet
for a short period, transitioning eventually to all snow by 10z.
Wet surfaces, such as runways, may experience a flash freeze as
the temperature drops. HON is mostly finished with precipitation
with just light flurries lingering over the next few hours, while
FSD to SUX and areas east will see the bulk of their precipitation
from now through 12z.
Precipitation should exit the region with ceilings improving to
VFR by late morning. Gusty post frontal northwest winds will
increase overnight and remain strong through Thursday with gusts
up to 35 kts expected. This may lead to reduced visibility due to
patchy blowing snow, mainly across northwest IA where snow
accumulations will be highest.
&&
.FSD WATCHES/WARNINGS/ADVISORIES...
SD...Winter Weather Advisory until 9 AM CST Thursday for SDZ070-071.
MN...Winter Weather Advisory until 9 AM CST Thursday for MNZ081-089-
090.
IA...Winter Weather Advisory until 9 AM CST Thursday for IAZ001-002-
012.
Winter Weather Advisory from 2 AM to noon CST Thursday for
IAZ003-013-014-020>022-031-032.
NE...Winter Weather Advisory until 9 AM CST Thursday for NEZ013.
Winter Weather Advisory from 2 AM to noon CST Thursday for
NEZ014.
&&
UPDATE...BP
SHORT TERM...SG
LONG TERM...SG
AVIATION...BPHazardous Weather Outlook...UPDATED National Weather Service Sioux Falls SD 641 PM CST Wed Feb 3 2021 IAZ001-002-012-MNZ081-089-090-NEZ013-SDZ070-071-041300- Lyon-Osceola-Sioux-Cottonwood-Nobles-Jackson-Dixon-Clay-Union- 641 PM CST Wed Feb 3 2021 This Hazardous Weather Outlook is for northwest Iowa, southwest Minnesota, northeast Nebraska and southeast South Dakota. .DAY ONE...Tonight. Scattered wintry mix changing to light snow is expected through early Thursday morning. While any snow accumulations are expected to be a few inches or less, gusty northwest winds may lead to areas of blowing snow, primarily east of I-29. Additionally, falling temperatures may lead to any wet road surfaces to re-freeze. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Bitterly cold Arctic air will dig into the region this weekend. High temperatures in the single digits and wind chills of 10 to 30 below zero are expected. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. IAZ003-013-014-020>022-031-032-NEZ014-041300- Dickinson-O'Brien-Clay-Plymouth-Cherokee-Buena Vista-Woodbury-Ida- Dakota- 641 PM CST Wed Feb 3 2021 This Hazardous Weather Outlook is for northwest Iowa, west central Iowa and northeast Nebraska. .DAY ONE...Tonight. A wintry mix changing to snow is expected late tonight through Thursday morning. While any snow accumulations are expected to be two inches or less, gusty northwest winds may lead to areas of blowing snow, primarily east of I-29. Additionally, falling temperatures may lead to any wet road surfaces to re-freeze. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Bitterly cold Arctic air will dig into the region this weekend. High temperatures in the single digits and wind chills of 10 to 30 below zero are expected. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. MNZ080-098-SDZ067-041300- Murray-Rock-Lincoln- 641 PM CST Wed Feb 3 2021 This Hazardous Weather Outlook is for southwest Minnesota and southeast South Dakota. .DAY ONE...Tonight. Scattered wintry mix changing to light snow is expected tonight into early Thursday morning. While any snow accumulations are expected to be a few inches or less, gusty northwest winds may lead to areas of blowing snow, primarily east of I-29. Additionally, falling temperatures may lead to any wet road surface to re-freeze. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Bitterly cold Arctic air will dig into the region this weekend. High temperatures in the single digits and wind chills of 10 to 30 below zero are expected. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time. MNZ071-072-097-SDZ038>040-050-052>066-068-069-041300- Lincoln-Lyon-Pipestone-Beadle-Kingsbury-Brookings-Gregory-Jerauld- Sanborn-Miner-Lake-Moody-Brule-Aurora-Davison-Hanson-McCook- Minnehaha-Charles Mix-Douglas-Hutchinson-Turner-Bon Homme-Yankton- 641 PM CST Wed Feb 3 2021 This Hazardous Weather Outlook is for southwest Minnesota, central South Dakota, east central South Dakota, south central South Dakota and southeast South Dakota. .DAY ONE...Tonight. Scattered wintry mix changing to light snow is expected through early Thursday morning. While any snow accumulations are expected to be around an inch or less, gusty northwest winds may lead to areas of blowing snow, primarily east of I-29. Additionally, falling temperatures may lead to any wet road surface to re-freeze. .DAYS TWO THROUGH SEVEN...Thursday through Tuesday. Bitterly cold Arctic air will dig into the region this weekend. High temperatures in the single digits and wind chills of 10 to 30 below zero are expected. .SPOTTER INFORMATION STATEMENT... Spotter activation is not expected at this time.
The national radar mosaic for the moment the first event began.
11 winter weather. Local standard time, as filed.
After a brief period of light freezing rain, snowfall was briefly heavy and totaled 1.0 inch at Rock Rapids. Roads became hazardous, and frequent wind gusts as high as 38 mph at Sheldon and 32 mph at Sioux Center produced several hours of blowing snow with visibility as low as one-half mile.
Snowfall was briefly heavy and totaled 2.0 inches at Sioux City. Roads became hazardous, and frequent wind gusts as high as 49 mph at Sioux City produced several hours of blowing snow with visibility as low as one-half mile.
After a brief period of light freezing rain, snowfall was briefly heavy and totaled 2.0 inches at Rock Valley. Roads became hazardous, and frequent wind gusts as high as 41 mph at Sioux Center produced several hours of blowing snow with visibility as low as one-half mile.
After a brief period of light freezing rain, snowfall was briefly heavy and totaled 1.5 inches at Sibley. Roads became hazardous, and frequent wind gusts as high as 38 mph at Sheldon and 31 mph at Worthington produced several hours of blowing snow with visibility as low as one-half mile.
Snowfall was briefly heavy and totaled 2.2 inches 5 miles north northwest of Holstein and 2.1 inches 3 miles northeast of Battle Creek. Roads became hazardous, and frequent wind gusts as high as 31 mph at Cherokee produced several hours of blowing snow with visibility as low as one-half to one mile.
After a brief period of light freezing rain, snowfall was briefly heavy and totaled 1.0 inch at Le Mars. Roads became hazardous, and frequent wind gusts as high as 35 mph at Le Mars produced several hours of blowing snow with visibility as low as one-half mile.
After a brief period of light freezing rain, snowfall was briefly heavy and totaled 2.5 inches 4 miles north of Cleghorn and 2.0 inches at Cherokee. Roads became hazardous, and frequent wind gusts as high as 31 mph at Cherokee produced several hours of blowing snow with visibility as low as one-half mile.
After a brief period of light freezing rain, snowfall was briefly heavy and totaled 2.8 inches at Sioux Rapids and 2.0 inches at Storm Lake. Roads became hazardous, and frequent wind gusts as high as 41 mph at Storm Lake produced several hours of blowing snow with visibility as low as one-half mile.
After a brief period of light freezing rain, snowfall was briefly heavy and totaled 1.6 inches 3 miles west northwest of Everly and 1.2 inches at Spencer. Roads became hazardous, and frequent wind gusts as high as 41 mph at Spencer produced several hours of blowing snow with visibility as low as one-half mile.
After a brief period of light freezing rain, snowfall was briefly heavy and totaled 2.0 inches at Primghar and 1.5 inches at Sanborn. Roads became hazardous, and frequent wind gusts as high as 38 mph at Sheldon produced several hours of blowing snow with visibility as low as one-half mile.
After a brief period of light freezing rain, snowfall was briefly heavy and totaled 3.6 inches 4 miles northwest of Milford and 2.4 inches near Spirit Lake. Roads became hazardous, and frequent wind gusts as high as 41 mph at Spencer and 38 mph at Jackson produced several hours of blowing snow with visibility as low as one-half mile.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Iowa in 2021Every state in 2021This day in weather historyWarnings in Iowa, February 2021
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: 942249, 942234, 942248, 942250, 942236, 942241, 942242, 942243, 942245, 942246, 942253.