On the morning of July 11th, a small complex of thunderstorms moved southeast from Nebraska, and down the Missouri River into far eastern Kansas and western Missouri. These thunderstorms created an outflow boundary on the western flank of the precipitation shield. This outflow boundary, combined with southwest winds just off the surface, became the focus for lift. The airmass across southern Kansas during the mid morning hours became very warm and unstable, which helped feed deep thunderstorm development over the Kansas City metropolitan area and points east. Rainfall rates were in excess of 2 inches per hour, with rainfall totals in the Kansas City area, ranging from 1 to 5 inches. This created urban flooding in some of the typical areas, such as Southwest Boulevard, Westport Avenue, and portions of the Plaza area. This rainfall created minor flooding on some area rivers and streams.
In addition to the heavy rainfall experienced, one thunderstorm over the south Kansas City area, intensified extremely fast. In a matter of 10 to 15 minutes, a strong core of rain and hail was lifted to between 30,000 and 40,000 ft high in the atmosphere, and just as quickly collapsed over the Hickman Mills and Ruskin Heights area of south Kansas City. Extensive tree damage was reported in a couple square mile area, with an estimated 1000 trees damaged or destroyed. Trees and trees limbs falling on power lines created extensive power outages, with around 29,000 residents without power after the height of the storm.

Hail in CLAY, MISSOURI
From 11-JUL-10 10:55:00 to 11-JUL-10 10:55:00 (CST-6)
Location: LIBERTY CITY ARPT
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in CASS, MISSOURI
From 11-JUL-10 12:26:00 to 11-JUL-10 12:26:00 (CST-6)
Location: FREEMAN
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Hail in CASS, MISSOURI
From 11-JUL-10 12:42:00 to 11-JUL-10 12:42:00 (CST-6)
Location: EVERETT
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in BATES, MISSOURI
From 11-JUL-10 14:14:00 to 11-JUL-10 14:14:00 (CST-6)
Location: PASSAIC
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Flash Flood in PETTIS, MISSOURI
From 11-JUL-10 12:30:00 to 11-JUL-10 18:30:00 (CST-6)
Location: GREEN RIDGE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

The emergency manager reported one and a half feet of water over Highway 127.

Flood in JACKSON, MISSOURI
From 11-JUL-10 08:24:00 to 11-JUL-10 14:24:00 (CST-6)
Location: KANSAS CITY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Up to 5 inches of water was reported at Roanoke and Westport Roads.

Thunderstorm Wind in CASS, MISSOURI
From 11-JUL-10 12:30:00 to 11-JUL-10 12:30:00 (CST-6)
Location: CREIGHTON
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm wind gusts were estimated to 70 mph on Highway 7, with many tree limbs reported down.

Thunderstorm Wind in HENRY, MISSOURI
From 11-JUL-10 13:12:00 to 11-JUL-10 13:12:00 (CST-6)
Location: WINDSOR
Magnitude: 61.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A barn was reported destroyed, and several trees up to a foot in diameter, were reported knocked over. A porch was detached from a house.

Hail in CASS, MISSOURI
From 11-JUL-10 15:25:00 to 11-JUL-10 15:25:00 (CST-6)
Location: LISLE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in HENRY, MISSOURI
From 11-JUL-10 13:06:00 to 11-JUL-10 13:06:00 (CST-6)
Location: CLINTON
Magnitude: 52.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: AWOS

Thunderstorm Wind in HENRY, MISSOURI
From 11-JUL-10 12:38:00 to 11-JUL-10 12:38:00 (CST-6)
Location: URICH
Magnitude: 56.00 EG
Property damage: 0.10K
Crop damage: 0.00K
Reported by: Trained Spotter

Four to five inch tree limbs were reported down, and a four feet by four feet sign, anchored by a steel post, was blown over.

Thunderstorm Wind in JACKSON, MISSOURI
From 11-JUL-10 08:44:00 to 11-JUL-10 08:44:00 (CST-6)
Location: RUSKIN HGTS
Magnitude: 56.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Sheds were reported damaged, and numerous trees up to a foot in diameter were felled, in the vicinity of Red Bridge and Hillcrest Roads. A steel power pole was knocked over at 108th and Bristol.

Hail in JACKSON, MISSOURI
From 11-JUL-10 08:44:00 to 11-JUL-10 08:44:00 (CST-6)
Location: DODSON
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Thunderstorm Wind in HENRY, MISSOURI
From 11-JUL-10 12:54:00 to 11-JUL-10 12:54:00 (CST-6)
Location: CLINTON
Magnitude: 61.00 EG
Property damage: 3.00K
Crop damage: 0.00K
Reported by: NWS Employee

The Morton building roof was peeled back. Large trees were uprooted and several large billboards were bent over.

Thunderstorm Wind in CASS, MISSOURI
From 11-JUL-10 11:43:00 to 11-JUL-10 11:43:00 (CST-6)
Location: HARRISONVILLE
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Thunderstorm winds were estimated to 65 mph.