An intense storm system moved across the Upper Midwest on December 15th and produced a rare severe weather outbreak across northeast Iowa. Eight tornadoes occurred across parts of Floyd, Chickasaw and Howard Counties. Four of these tornadoes were rated EF1 with one moving through Rudd (Floyd County) where the roof was removed from the library and several homes and a church were heavily damaged. The other tornadoes largely moved through rural areas damaging trees, power lines and farm buildings. In addition to the tornadoes, damaging winds occurred that blew over a semi in Floyd (Floyd County) and damaged numerous homes across the region. The Governor of Iowa declared a state of disaster emergency for Allamakee, Chickasaw, Fayette, Floyd, Howard, Mitchell and Winneshiek Counties. A federal disaster was declared for Floyd, Howard and Mitchell Counties.

Tornado in CHICKASAW, IOWA
From 15-DEC-21 19:17:00 to 15-DEC-21 19:21:00 (CST-6)
Location: DEERFIELD
Tornado F-scale: EF0
Property damage: 330.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

The second tornado of the night in Chickasaw County formed southwest of Alta Vista and moved northeast before crossing into Howard County along County Line Road just east of the Little Wapsipinicon River. This tornado was rated EF0. The tornado damaged a greenhouse facility, otherwise, damage was limited to trees.

Tornado in HOWARD, IOWA
From 15-DEC-21 19:29:00 to 15-DEC-21 19:32:00 (CST-6)
Location: SCHLEY
Tornado F-scale: EF0
Property damage: 600.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This was the third tornado of the night in Howard County. This EF0 tornado formed west of Schley and move northeast before dissipating east of Davis Corners. This tornado removed the roof from a hog farm building, drove lumber through the side of a metal building and also damaged other outbuildings and trees. One house had broken windows and some damage from tree branches downed on it.

Thunderstorm Wind in HOWARD, IOWA
From 15-DEC-21 19:28:00 to 15-DEC-21 19:28:00 (CST-6)
Location: DAVIS CORNERS
Magnitude: 56.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Public

Trees were uprooted, power poles snapped and a metal barn roof was partially blown off west of Davis Corners.

Thunderstorm Wind in MITCHELL, IOWA
From 15-DEC-21 19:06:00 to 15-DEC-21 19:06:00 (CST-6)
Location: MEROA
Magnitude: 67.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A house near Rose Creek sustained wind damage.

Thunderstorm Wind in CHICKASAW, IOWA
From 15-DEC-21 19:15:00 to 15-DEC-21 19:15:00 (CST-6)
Location: IONIA
Magnitude: 55.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

A 63 mph wind gust was measured by a mesonet sensor north of Ionia.

Thunderstorm Wind in HOWARD, IOWA
From 15-DEC-21 19:30:00 to 15-DEC-21 19:30:00 (CST-6)
Location: SCHLEY
Magnitude: 54.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Trained Spotter

An outbuilding and structures on a hog farm southwest of Cresco were damaged.

Thunderstorm Wind in HOWARD, IOWA
From 15-DEC-21 19:37:00 to 15-DEC-21 19:37:00 (CST-6)
Location: CRESCO MUNI ARPT
Magnitude: 51.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Power outages occurred in Cresco from downed power lines. The power outages were not repaired until the afternoon of December 16th.

Thunderstorm Wind in ALLAMAKEE, IOWA
From 15-DEC-21 20:20:00 to 15-DEC-21 20:20:00 (CST-6)
Location: WAUKON
Magnitude: 50.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Newspaper

Power poles, lines and trees were blown down in Waukon. Almost 2,700 customers lost power because of the downed poles and lines.

Thunderstorm Wind in MITCHELL, IOWA
From 15-DEC-21 19:05:00 to 15-DEC-21 19:05:00 (CST-6)
Location: MEROA
Magnitude: 67.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Trees were snapped off near Rose Creek.

Thunderstorm Wind in FLOYD, IOWA
From 15-DEC-21 19:03:00 to 15-DEC-21 19:03:00 (CST-6)
Location: RUDD
Magnitude: 71.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Trees were snapped off north of Rudd.

Thunderstorm Wind in WINNESHIEK, IOWA
From 15-DEC-21 19:50:00 to 15-DEC-21 19:50:00 (CST-6)
Location: BURR OAK
Magnitude: 50.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Trees were blown down near Burr Oak.

Tornado in HOWARD, IOWA
From 15-DEC-21 19:31:00 to 15-DEC-21 19:35:00 (CST-6)
Location: SCHLEY
Tornado F-scale: EF0
Property damage: 250.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This was the fourth tornado of the night across Howard County. This EF0 tornado formed northeast of Schley and moved northeast before dissipating west of Cresco. This tornado caused damage to one farm where a house was effectively destroyed by large trees blown down on it. At another farm, the home sustained roof damage from a large tree downed on it along with broken windows and two metal outbuildings were destroyed with a third damaged.

Thunderstorm Wind in FLOYD, IOWA
From 15-DEC-21 18:58:00 to 15-DEC-21 18:58:00 (CST-6)
Location: ROSEVILLE
Magnitude: 68.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Trees were snapped off, large branches blown down and a small farm outbuilding damaged northeast of Marble Rock.

Thunderstorm Wind in FLOYD, IOWA
From 15-DEC-21 18:55:00 to 15-DEC-21 18:55:00 (CST-6)
Location: MARBLE ROCK
Magnitude: 69.00 EG
Property damage: 15.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

A large metal grain bin was dented near the top and a metal roof was blown off a building in Marble Rock.

Thunderstorm Wind in FLOYD, IOWA
From 15-DEC-21 18:57:00 to 15-DEC-21 18:57:00 (CST-6)
Location: MARBLE ROCK
Magnitude: 71.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Large tree branches were blown down northeast of Marble Rock.

Tornado in FLOYD, IOWA
From 15-DEC-21 18:59:00 to 15-DEC-21 19:04:00 (CST-6)
Location: MARBLE ROCK
Tornado F-scale: EF1
Property damage: 490.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado formed just north of Marble Rock and moved rapidly to the northeast before dissipating west of Charles City. An NWS survey team determined this tornado to have an EF1 rating. The tornado caused damage to homes, farm buildings and metal grain bins along with taking down power poles, power lines and trees.

Thunderstorm Wind in HOWARD, IOWA
From 15-DEC-21 19:35:00 to 15-DEC-21 19:35:00 (CST-6)
Location: LIME SPGS
Magnitude: 57.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: Newspaper

The tarp roof was blown off a livestock shed northeast of Lime Springs.

Thunderstorm Wind in FLOYD, IOWA
From 15-DEC-21 19:04:00 to 15-DEC-21 19:04:00 (CST-6)
Location: CARRVILLE
Magnitude: 65.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Broadcast Media

A small shed and a metal outbuilding were blown over and destroyed south of Charles City.

Tornado in FLOYD, IOWA
From 15-DEC-21 19:06:00 to 15-DEC-21 19:07:00 (CST-6)
Location: RUDD
Tornado F-scale: EF1
Property damage: 1.15M
Crop damage: 0.00K
Reported by: NWS Storm Survey

The third tornado of the night in Floyd County formed just to the southwest of Rudd, moved northeast directly through the town and dissipated along Business U.S. Highway 18 on the north edge of town. Extensive damage occurred in the town with numerous homes sustaining damage with some roofs completely blown off. The roof of the library was removed with damage sustained to almost all the books in the building. A church on the north side of town also sustained heavy damage as did the towns water treatment plant. Water and power were not expected to be restored for several days. Classes for the Rudd-Rockford-Marble Rock school district were canceled for December 16th but the building in Rockford was open to the public for showers, warmth and served breakfast and lunch to those in need.

Tornado in CHICKASAW, IOWA
From 15-DEC-21 19:15:00 to 15-DEC-21 19:18:00 (CST-6)
Location: BASSETT
Tornado F-scale: EF1
Property damage: 255.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

An EF1 tornado formed west of North Washington and moved to northeast for about 4 miles before dissipating. The tornado damaged trees and some farm outbuilding along its path.

Thunderstorm Wind in FLOYD, IOWA
From 15-DEC-21 18:58:00 to 15-DEC-21 18:58:00 (CST-6)
Location: ROSEVILLE
Magnitude: 64.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Trees were snapped off north of Marble Rock.

Thunderstorm Wind in HOWARD, IOWA
From 15-DEC-21 19:22:00 to 15-DEC-21 19:22:00 (CST-6)
Location: ELMA
Magnitude: 56.00 EG
Property damage: 25.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Farm outbuildings were damaged east of Elma.

Thunderstorm Wind in CHICKASAW, IOWA
From 15-DEC-21 19:16:00 to 15-DEC-21 19:16:00 (CST-6)
Location: DEERFIELD
Magnitude: 50.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Trees were snapped off southwest of Alta Vista.

Thunderstorm Wind in FLOYD, IOWA
From 15-DEC-21 19:03:00 to 15-DEC-21 19:03:00 (CST-6)
Location: FLOYD
Magnitude: 57.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Public

A semi-truck and trailer were blown over at a truck stop in Floyd.

Thunderstorm Wind in FLOYD, IOWA
From 15-DEC-21 19:00:00 to 15-DEC-21 19:00:00 (CST-6)
Location: FOLKERTS FLD ARPT
Magnitude: 52.00 EG
Property damage: 30.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

A roof was blown off a building near the entrance to Rudd Park.

Thunderstorm Wind in MITCHELL, IOWA
From 15-DEC-21 19:11:00 to 15-DEC-21 19:11:00 (CST-6)
Location: OSAGE
Magnitude: 55.00 EG
Property damage: 40.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Part of a roof was blown off a house and a garage door blown in at a residence in Osage.

Thunderstorm Wind in HOWARD, IOWA
From 15-DEC-21 19:34:00 to 15-DEC-21 19:34:00 (CST-6)
Location: VERNON SPGS
Magnitude: 57.00 EG
Property damage: 75.00K
Crop damage: 0.00K
Reported by: Newspaper

A metal machine building was destroyed west of Cresco.

Thunderstorm Wind in HOWARD, IOWA
From 15-DEC-21 19:35:00 to 15-DEC-21 19:35:00 (CST-6)
Location: CRESCO MUNI ARPT
Magnitude: 57.00 EG
Property damage: 50.00K
Crop damage: 0.00K
Reported by: Newspaper

A metal pole shed was blown off its foundation just west of Cresco.

Tornado in FLOYD, IOWA
From 15-DEC-21 18:54:00 to 15-DEC-21 18:57:00 (CST-6)
Location: AUREOLA
Tornado F-scale: EF1
Property damage: 5.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado formed in Butler County before crossing into southern Floyd County south of Marble Rock. The tornado remained on the ground for about 3 minutes in Floyd County as it moved across rural areas before dissipating south of Marble Rock. An NWS survey team determined this tornado to have an EF1 rating with damage limited to trees.

Tornado in HOWARD, IOWA
From 15-DEC-21 19:21:00 to 15-DEC-21 19:22:00 (CST-6)
Location: ELMA
Tornado F-scale: EF0
Property damage: 90.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado formed in Chickasaw County and moved into Howard County south of Elma along County Line Road just east of the Little Wapsipinicon River. The tornado moved rapidly northeast before dissipating south of Elma. Damage from this EF0 tornado was limited to trees and one farm.

Thunderstorm Wind in MITCHELL, IOWA
From 15-DEC-21 19:09:00 to 15-DEC-21 19:09:00 (CST-6)
Location: MITCHELL
Magnitude: 60.00 EG
Property damage: 175.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Several buildings were flattened on a large farm just outside of Mitchell.

Tornado in HOWARD, IOWA
From 15-DEC-21 19:23:00 to 15-DEC-21 19:28:00 (CST-6)
Location: ELMA
Tornado F-scale: EF0
Property damage: 90.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This was the second tornado of the night in Howard County. This EF0 tornado formed northeast of Elma and moved northeast before dissipating east of Saratoga. Damage along the path was limited to trees and weak farm outbuildings.

Thunderstorm Wind in HOWARD, IOWA
From 15-DEC-21 19:20:00 to 15-DEC-21 19:20:00 (CST-6)
Location: ELMA
Magnitude: 51.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Public

Trees were blown down north of Elma.

Hail in FLOYD, IOWA
From 15-DEC-21 19:06:00 to 15-DEC-21 19:06:00 (CST-6)
Location: CHARLES CITY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Quarter sized hail fell in Charles City.

Thunderstorm Wind in MITCHELL, IOWA
From 15-DEC-21 19:09:00 to 15-DEC-21 19:09:00 (CST-6)
Location: MITCHELL
Magnitude: 67.00 EG
Property damage: 75.00K
Crop damage: 0.00K
Reported by: Broadcast Media

A hog barn and another barn were destroyed on a farm northwest of Osage.