Conditions became moderately to highly unstable across eastern Nebraska and southwest Iowa by early afternoon on August 18th ahead of a weak slow moving cold front that was driven southeast by a weak upper level disturbance.  Scattered super-cell thunderstorms developed by early afternoon near the northeast Nebraska and South Dakota border and tracked and developed southeast across eastern Nebraska and southwest Iowa through the afternoon and evening hours for a prolonged severe weather event across the area.  Several of the storms produced very large destructive hail and very strong wind gusts which destroyed crops and caused property damage over large areas, notably Page county.  As of the second week in September, State Farm Insurance stated it had processed around 6,600 homeowner and 5,200 auto claims in Iowa from the storm.

Hail in MONTGOMERY, IOWA
From 18-AUG-11 17:05:00 to 18-AUG-11 17:10:00 (CST-6)
Location: VILLISCA
Magnitude: 1.75 
Reported by: Newspaper

Hail at least up to golf ball-size was accompanied by thunderstorm wind gusts estimated at over 60 mph.  The winds and hail caused extensive tree, vehicle and home damage in the area.

Thunderstorm Wind in POTTAWATTAMIE, IOWA
From 18-AUG-11 16:26:00 to 18-AUG-11 16:37:00 (CST-6)
Location: COUNCIL BLUFFS
Magnitude: 52.00 EG
Reported by: Amateur Radio

Thunderstorm wind gusts estimated at around 60 mph accompanied hail that reached up to baseball-size in the Council Bluffs area.  The wind driven hail caused extensive damage to homes, vehicles and trees around town.

Hail in MONONA, IOWA
From 18-AUG-11 16:54:00 to 18-AUG-11 16:54:00 (CST-6)
Location: ONAWA
Magnitude: 1.25 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Hail in POTTAWATTAMIE, IOWA
From 18-AUG-11 15:40:00 to 18-AUG-11 15:50:00 (CST-6)
Location: HANCOCK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail up to quarter-size lasted for around 10 minutes.

Hail in POTTAWATTAMIE, IOWA
From 18-AUG-11 16:26:00 to 18-AUG-11 16:37:00 (CST-6)
Location: COUNCIL BLUFFS
Magnitude: 2.75 
Reported by: Amateur Radio

Hail up to baseball-size which was accompanied by thunderstorm wind gusts estimated at around 60 mph caused extensive damage to homes and vehicles in the Council Bluffs area.  Iowa Western Community College had at least a million dollars worth of damage to buildings, mainly to roofs, windows and siding, according to the college's vice president of marketing and public relations.

Thunderstorm Wind in MONTGOMERY, IOWA
From 18-AUG-11 16:55:00 to 18-AUG-11 16:55:00 (CST-6)
Location: RED OAK
Magnitude: 56.00 MG
Reported by: AWOS

A thunderstorm wind gust of 64 mph was measured at the Red Oak Awos.  The strong winds severely damaged a hanger at the Red Oak airport and dropped some trees onto homes in the region.

Hail in MONTGOMERY, IOWA
From 18-AUG-11 17:03:00 to 18-AUG-11 17:08:00 (CST-6)
Location: WALLIN
Magnitude: 2.75 
Reported by: Trained Spotter

Hail up to baseball-size was accompanied by thunderstorm wind gusts estimated at around 70 mph around the Stanton area.  Some crops north of Stanton were destroyed and vehicle and home damage was noted across the area.

Hail in HARRISON, IOWA
From 18-AUG-11 17:44:00 to 18-AUG-11 17:44:00 (CST-6)
Location: WOODBINE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in SHELBY, IOWA
From 18-AUG-11 17:57:00 to 18-AUG-11 17:57:00 (CST-6)
Location: HARLAN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in PAGE, IOWA
From 18-AUG-11 18:00:00 to 18-AUG-11 18:15:00 (CST-6)
Location: COIN
Magnitude: 60.00 EG
Reported by: Trained Spotter

Thunderstorm wind gusts estimated at around 70 mph and at least one inch hail caused extensive damage in a swath from Shambaugh through College Springs, Coin and into the Braddyville area.  Numerous north or east facing windows and siding across these areas were broken out or damaged, power lines and trees were downed and crop damage was extensive.  More than 80 power poles were snapped from Highway 2 to south of Coin, and the downed poles and lines essentially closed off the south or east routes in or out of town.  Some residents claimed it was the worst storm that they had ever witnessed.

Hail in PAGE, IOWA
From 18-AUG-11 18:00:00 to 18-AUG-11 18:15:00 (CST-6)
Location: COIN
Magnitude: 1.00 
Reported by: Storm Chaser

Hail at least 1 inch in diameter was accompanied by thunderstorm wind gusts estimated at around 70 mph.  The wind driven hail caused extensive damage in a swath from Shambaugh through College Springs and into the Braddyville area.   Numerous north or east facing windows and siding were broken out or damaged, power lines and trees were downed and crop damage was extensive.  More than 80 power poles were snapped from Highway 2 to south of Coin.  Some residents claimed it was the worst storm they had ever witnessed.

Hail in HARRISON, IOWA
From 18-AUG-11 18:05:00 to 18-AUG-11 18:05:00 (CST-6)
Location: MISSOURI VLY
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Near the intersection of Highway 30 and I29.

Hail in PAGE, IOWA
From 18-AUG-11 18:09:00 to 18-AUG-11 18:24:00 (CST-6)
Location: CLARINDA MUNI ARPT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

The hail lasted for around 15 minutes.

Hail in POTTAWATTAMIE, IOWA
From 18-AUG-11 18:33:00 to 18-AUG-11 18:33:00 (CST-6)
Location: UNDERWOOD
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Hail in MILLS, IOWA
From 18-AUG-11 18:48:00 to 18-AUG-11 18:48:00 (CST-6)
Location: GLENWOOD
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in MILLS, IOWA
From 18-AUG-11 18:53:00 to 18-AUG-11 18:53:00 (CST-6)
Location: GLENWOOD
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Pea to quarter-size hail was reported by the public in the Glenwood area.  The hail was accompanied by wind gusts estimated at 60 mph or stronger.

Hail in FREMONT, IOWA
From 18-AUG-11 19:13:00 to 18-AUG-11 19:13:00 (CST-6)
Location: RANDOLPH
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in FREMONT, IOWA
From 18-AUG-11 19:33:00 to 18-AUG-11 19:33:00 (CST-6)
Location: FARRAGUT
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in PAGE, IOWA
From 18-AUG-11 19:55:00 to 18-AUG-11 19:55:00 (CST-6)
Location: CLARINDA
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Thunderstorm wind gusts were measured at 58 mph by the Awos in Clarinda.

Thunderstorm Wind in MONONA, IOWA
From 18-AUG-11 13:16:00 to 18-AUG-11 13:16:00 (CST-6)
Location: MAPLETON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

The public estimated that thunderstorm wind gusts reached around 60 mph.

Thunderstorm Wind in PAGE, IOWA
From 18-AUG-11 19:50:00 to 18-AUG-11 19:50:00 (CST-6)
Location: SHENANDOAH
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Thunderstorm wind gusts estimated at around 60 mph downed several trees in the Shenandoah area.

Thunderstorm Wind in FREMONT, IOWA
From 18-AUG-11 19:30:00 to 18-AUG-11 19:30:00 (CST-6)
Location: SIDNEY
Magnitude: 60.00 EG
Reported by: Newspaper

Thunderstorm wind gusts estimated at around 70 mph caused extensive tree and property damage in the Sidney area.  The county Chief Deputy reported that there was a tree down on about every block.  Pieces of a roof of an auto parts store blew off and damaged several vehicles in the area and a grocery store lost several windows.  A barn collapsed from the winds as well.  Power poles were snapped and the power was lost across a large part of the area.

Hail in MILLS, IOWA
From 18-AUG-11 16:40:00 to 18-AUG-11 16:50:00 (CST-6)
Location: MINEOLA
Magnitude: 3.00 
Reported by: Newspaper

Hail, some as large as around softball-size, was accompanied by thunderstorm winds estimated at 60 mph or stronger.  The hail and strong winds caused considerable home and vehicle damage in the Mineola area, especially on the east side of the structures.  It was reported that almost every home in town lost at least one window.  Bicyclists on a weekly jaunt on a local trail were hit by the wind and hail with several sustaining minor injuries due to the wind driven hail.

Thunderstorm Wind in MILLS, IOWA
From 18-AUG-11 16:40:00 to 18-AUG-11 16:50:00 (CST-6)
Location: MINEOLA
Magnitude: 55.00 EG
Reported by: Newspaper

Hail, some as large as softball-size, was accompanied by thunderstorm winds estimated at 60 mph or stronger.  The hail and strong winds caused considerable home and vehicle damage in the Mineola area, especially on the east side of the structures.  Bicyclists on a weekly jaunt on a local trail were hit by the wind and hail with several sustaining minor injuries due to the wind driven hail.

Thunderstorm Wind in SHELBY, IOWA
From 18-AUG-11 15:00:00 to 18-AUG-11 15:00:00 (CST-6)
Location: HARLAN
Magnitude: 56.00 MG
Reported by: Emergency Manager

Thunderstorm winds were measured at 65 mph a few miles northwest of Harlan.  The winds flattened grain bins in the area and a couple of outbuildings were destroyed.  A thousand gallon propane tank was moved around 10 feet by the winds.

Hail in SHELBY, IOWA
From 18-AUG-11 15:16:00 to 18-AUG-11 15:16:00 (CST-6)
Location: SHELBY
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Nickel-size hail fell along with thunderstorm wind gusts estimated at around 50 mph.

Thunderstorm Wind in MILLS, IOWA
From 18-AUG-11 18:53:00 to 18-AUG-11 18:53:00 (CST-6)
Location: GLENWOOD
Magnitude: 55.00 EG
Reported by: Emergency Manager

Pea to quarter-size hail was accompanied by wind gusts estimated at 60 mph or stronger.  Trees and large tree limbs were downed in the area and some vehicle and home damage was noted.

Thunderstorm Wind in MONTGOMERY, IOWA
From 18-AUG-11 17:03:00 to 18-AUG-11 17:08:00 (CST-6)
Location: STANTON
Magnitude: 60.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail up to baseball-size was accompanied by thunderstorm wind gusts estimated at around 70 mph around the Stanton area.  Some crops north of Stanton were destroyed and vehicle and home damage was noted across the area.

Hail in HARRISON, IOWA
From 18-AUG-11 15:49:00 to 18-AUG-11 15:49:00 (CST-6)
Location: MODALE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in MONTGOMERY, IOWA
From 18-AUG-11 17:05:00 to 18-AUG-11 17:10:00 (CST-6)
Location: VILLISCA
Magnitude: 55.00 EG
Reported by: Emergency Manager

Thunderstorm wind gusts estimated at over 60 mph severely damaged some grain bins in the Villisca area and caused widespread tree damage as well.  Some of the fallen trees damaged homes and vehicles and the winds were accompanied by hail at least golf ball-size which also damaged vehicles and homes.

Hail in MONONA, IOWA
From 18-AUG-11 16:40:00 to 18-AUG-11 16:40:00 (CST-6)
Location: WHITING
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in SHELBY, IOWA
From 18-AUG-11 15:12:00 to 18-AUG-11 15:12:00 (CST-6)
Location: TENNANT
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement