A low pressure system brought strong (both thunderstorm, and non-thunderstorm) winds, tornadoes, dust, snow, and record temperatures into eastern Nebraska and western Iowa. The event was determined to be a derecho meeting the criteria of wind damage.

Thunderstorm Wind in POTTAWATTAMIE, IOWA
From 15-DEC-21 16:20:00 to 15-DEC-21 16:20:00 (CST-6)
Location: LAKE MANAWA
Magnitude: 54.00 MG
Reported by: Mesonet

Mesonet measured a peak wind gust of 62 mph.

Thunderstorm Wind in POTTAWATTAMIE, IOWA
From 15-DEC-21 16:21:00 to 15-DEC-21 16:21:00 (CST-6)
Location: LAKE MANAWA
Magnitude: 80.00 EG
Reported by: Public

Public reported nine loaded coal cars rolled off the track.

Thunderstorm Wind in POTTAWATTAMIE, IOWA
From 15-DEC-21 16:24:00 to 15-DEC-21 16:24:00 (CST-6)
Location: WESTON
Magnitude: 65.00 EG
Reported by: Emergency Manager

Fire chief reported power lines and power poles down for about 1/4 mile.

Thunderstorm Wind in POTTAWATTAMIE, IOWA
From 15-DEC-21 16:29:00 to 15-DEC-21 16:29:00 (CST-6)
Location: TREYNOR
Magnitude: 65.00 EG
Reported by: Emergency Manager

Emergency manager reported a large tree on a house.

Thunderstorm Wind in POTTAWATTAMIE, IOWA
From 15-DEC-21 16:29:00 to 15-DEC-21 16:29:00 (CST-6)
Location: WESTON
Magnitude: 74.00 EG
Reported by: Emergency Manager

Emergency manager reported a roof blown of a house.

Thunderstorm Wind in POTTAWATTAMIE, IOWA
From 15-DEC-21 16:36:00 to 15-DEC-21 16:36:00 (CST-6)
Location: CHAUTAUQUA
Magnitude: 69.00 MG
Reported by: AWOS

Council Bluffs AWOS measured a peak wind gust of 79 mph.

Thunderstorm Wind in POTTAWATTAMIE, IOWA
From 15-DEC-21 16:53:00 to 15-DEC-21 16:53:00 (CST-6)
Location: AVOCA
Magnitude: 65.00 EG
Reported by: Storm Chaser

Storm chaser reported a semi rolled over on I80.

Thunderstorm Wind in SHELBY, IOWA
From 15-DEC-21 16:55:00 to 15-DEC-21 16:55:00 (CST-6)
Location: HARLAN
Magnitude: 63.00 MG
Reported by: AWOS

Harlan AWOS measured a peak wind gust of 72 mph.

Thunderstorm Wind in PAGE, IOWA
From 15-DEC-21 17:15:00 to 15-DEC-21 17:15:00 (CST-6)
Location: CLARINDA MUNI ARPT
Magnitude: 53.00 MG
Reported by: AWOS

Clarinda AWOS measured a peak wind gust of 61 mph.

Tornado in POTTAWATTAMIE, IOWA
From 15-DEC-21 16:16:00 to 15-DEC-21 16:17:00 (CST-6)
Location: LAKE MANAWA
Tornado F-scale: EF0
Reported by: NWS Storm Survey

A short-lived tornado caused minimal damage to trees in a mostly open area of the Missouri River bottom. The presence of a tornado was supported by photographic evidence taken from northeast of the track and triangulated to this approximate location. No additional tornado-driven damage was identified in the heavily forested areas southwest of the river.

Thunderstorm Wind in POTTAWATTAMIE, IOWA
From 15-DEC-21 16:38:00 to 15-DEC-21 16:38:00 (CST-6)
Location: UNDERWOOD
Magnitude: 70.00 MG
Reported by: Emergency Manager

Emergency manager reported a measured peak wind gust of 80 mph.

Thunderstorm Wind in POTTAWATTAMIE, IOWA
From 15-DEC-21 16:40:00 to 15-DEC-21 16:40:00 (CST-6)
Location: CARSON
Magnitude: 65.00 EG
Reported by: Public

Public reported a machine shed destroyed.

Thunderstorm Wind in SHELBY, IOWA
From 15-DEC-21 16:41:00 to 15-DEC-21 16:41:00 (CST-6)
Location: TENNANT
Magnitude: 65.00 EG
Reported by: Emergency Manager

Emergency manager reported that a large tree fell on a home.

Thunderstorm Wind in POTTAWATTAMIE, IOWA
From 15-DEC-21 16:50:00 to 15-DEC-21 16:50:00 (CST-6)
Location: AVOCA
Magnitude: 58.00 MG
Reported by: Mesonet

Mesonet station RAVI4 measured a peak wind gust of 67 mph.

Tornado in POTTAWATTAMIE, IOWA
From 15-DEC-21 16:31:00 to 15-DEC-21 16:36:00 (CST-6)
Location: BENTLEY
Tornado F-scale: EF2
Reported by: NWS Storm Survey

A narrow EF-2 tornado began producing damage near Mahogany Road and 290th St and tracked north northeast into the southeast edge of Neola and then caused intermittent damage near Railroad Highway North of Neola. The most significant damage was to a home along 290th street where the roof was removed and walls blown out. A nearby garage was moved off of its foundation and approximately 10 mature trees were all uprooted behind the home with substantial damage to hardwood trees in the front yard. The narrow nature of this tornado was evident in the damage path as nearby barns on the east side of the track had low-end damage, possibly owing to the significant forward speed of the tornado. The tornado was seen briefly by the resident before seeking shelter. A business on the southeast side of Neola also had substantial damage to large metal buildings, at least two of which were destroyed.

Tornado in POTTAWATTAMIE, IOWA
From 15-DEC-21 16:34:00 to 15-DEC-21 16:42:00 (CST-6)
Location: MACEDONIA
Tornado F-scale: EF1
Reported by: NWS Storm Survey

A tornado tracked from east of Macedonia to east of Oakland, causing intermittent damage to trees, outbuildings, and homes along the track.

High Wind in MILLS, IOWA
From 15-DEC-21 14:03:00 to 15-DEC-21 14:03:00 (CST-6)
Magnitude: 52.00 MG
Reported by: Public

Public reported a measured peak wind gust of 60 mph.

High Wind in MONTGOMERY, IOWA
From 15-DEC-21 13:35:00 to 15-DEC-21 13:35:00 (CST-6)
Magnitude: 50.00 MG
Reported by: AWOS

Red Oak Airport measured a peak wind gust of 58 mph.

High Wind in PAGE, IOWA
From 15-DEC-21 18:55:00 to 15-DEC-21 18:55:00 (CST-6)
Magnitude: 60.00 MG
Reported by: AWOS

Clarinda AWOS measured a peak wind gust of 69 mph.

Tornado in POTTAWATTAMIE, IOWA
From 15-DEC-21 16:24:00 to 15-DEC-21 16:27:00 (CST-6)
Location: WESTON
Tornado F-scale: EF2
Reported by: NWS Storm Survey

A narrow but strong tornado tracked along Road L34 through Sherwood Country Estates before ending near Juniper Road. The maximum damage was sustained to a home in Sherwood Country Estates where the narrow tornado removed the majority of a homes roof and damaged other nearby homes as well.

Tornado in MILLS, IOWA
From 15-DEC-21 16:31:00 to 15-DEC-21 16:32:00 (CST-6)
Location: HENDERSON
Tornado F-scale: EF1
Reported by: NWS Storm Survey

A short-lived tornado developed on a farm where it quickly destroyed a metal building structure, flipping two trucks that were parked inside the building. The roof was flipped off of the structure and debris was distributed to the northeast. The tornado then impacted and snapped several wood power poles but did not cause any additional significant or highly focused damage.

Tornado in MILLS, IOWA
From 15-DEC-21 16:14:00 to 15-DEC-21 16:23:00 (CST-6)
Location: TABOR
Tornado F-scale: EF1
Reported by: NWS Storm Survey

The tornado began in the hills and rough terrain near Pease Rd and Quigg Ave, and traveled quickly northeast along the 10 mile track, lasting approximately 9 minutes. The first few miles of the tornado track were intermittent, with occasional evidence of a narrow track of damage and some substantial damage to outbuildings and trees. The damage became much more consistent as the tornado approached US Highway 275 where it damaged several outbuildings, including destruction of a well-constructed metal buildings with wooden frame. Security camera footage at this location supported the likelihood of this being caused by a tornado due to sudden directional and vertical shifts in wind which the removal of the roof and walls was completed in only 1 to 2 seconds. The tornado track continued northeast where it caused substantial tree damage, destroyed two sheds, caused minor damage to homes and snapped numerous power poles. Even at this location where the damage footprint was relatively wide, the individual tornado vortices were small, with a significant swath of wind along its eastern flank. The tornado continued north with gradually decreasing damage intensity and sporadic nature of damage.