On July 27, 28, and 29, multiple thunderstorms developed near a slowly moving cold front which spread across northeast Kansas. The very warm surface conditions led to an environment that was supportive of downbursts. A few of the thunderstorms quickly intensified, but with lack of any mid-level shear to support the updrafts; the storms quickly collapsed upon themselves, bringing strong downpours and damaging winds. The most intense of these downburst thunderstorms formed in Ottawa County and brought 70 to 80 mph winds to areas near Wells and Oak Hill.  Numerous outbuildings were destroyed and trees uprooted as a result of the damaging wind gusts. Areas of Riley and Pottawatomie Counties also recieved strong winds, and in Jefferson County, a boating dock broke loose from the Lake Perry Marina.

Thunderstorm Wind in DICKINSON, KANSAS
From 27-JUL-11 17:30:00 to 27-JUL-11 17:31:00 (CST-6)
Location: ENTERPRISE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter estimates winds of 60 mph.

Thunderstorm Wind in GEARY, KANSAS
From 27-JUL-11 19:34:00 to 27-JUL-11 19:35:00 (CST-6)
Location: (FRI)MARSHALL AAF FT
Magnitude: 60.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: ASOS

Thunderstorm Wind in RILEY, KANSAS
From 27-JUL-11 19:52:00 to 27-JUL-11 19:54:00 (CST-6)
Location: MANHATTAN
Magnitude: 74.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter estimated winds of 85 mph.

Thunderstorm Wind in DICKINSON, KANSAS
From 27-JUL-11 19:00:00 to 27-JUL-11 19:02:00 (CST-6)
Location: UPLAND
Magnitude: 52.00 EG
Reported by: Trained Spotter

Four inch diameter limbs blown down.

Thunderstorm Wind in GEARY, KANSAS
From 27-JUL-11 19:25:00 to 27-JUL-11 19:27:00 (CST-6)
Location: (FRI)MARSHALL AAF FT
Magnitude: 61.00 EG
Reported by: Trained Spotter

Delayed report of pieces of siding and roofing being blown off. A small shed was ripped apart and pieces of it were thrown. A 12 foot trailer was thrown approx. 350 feet. Minor tree damage also reported.

Thunderstorm Wind in OTTAWA, KANSAS
From 28-JUL-11 19:12:00 to 28-JUL-11 19:14:00 (CST-6)
Location: WELLS
Magnitude: 70.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter estimated 80 mph wind gust.

Thunderstorm Wind in OTTAWA, KANSAS
From 28-JUL-11 19:10:00 to 28-JUL-11 19:11:00 (CST-6)
Location: WELLS
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public estimate of 70 mph winds.

Thunderstorm Wind in OTTAWA, KANSAS
From 28-JUL-11 19:24:00 to 28-JUL-11 19:25:00 (CST-6)
Location: VINE CREEK
Magnitude: 61.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter estimate of 70 mph winds.

Thunderstorm Wind in OTTAWA, KANSAS
From 28-JUL-11 19:26:00 to 28-JUL-11 19:28:00 (CST-6)
Location: VINE CREEK
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public estimated of 65 mph winds.

Thunderstorm Wind in POTTAWATOMIE, KANSAS
From 28-JUL-11 20:45:00 to 28-JUL-11 20:46:00 (CST-6)
Location: GARRISON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter estimates 60 mph winds.

Thunderstorm Wind in POTTAWATOMIE, KANSAS
From 28-JUL-11 21:10:00 to 28-JUL-11 21:11:00 (CST-6)
Location: WESTMORELAND
Magnitude: 56.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter estimates winds of 60 to 65 mph.

Hail in OTTAWA, KANSAS
From 28-JUL-11 18:55:00 to 28-JUL-11 18:55:00 (CST-6)
Location: BENNINGTON
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in OTTAWA, KANSAS
From 28-JUL-11 19:10:00 to 28-JUL-11 19:11:00 (CST-6)
Location: WELLS
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in OTTAWA, KANSAS
From 28-JUL-11 19:24:00 to 28-JUL-11 19:25:00 (CST-6)
Location: VINE CREEK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in OTTAWA, KANSAS
From 28-JUL-11 19:26:00 to 28-JUL-11 19:27:00 (CST-6)
Location: VINE CREEK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Thunderstorm Wind in OTTAWA, KANSAS
From 28-JUL-11 19:32:00 to 28-JUL-11 19:34:00 (CST-6)
Location: VINE CREEK
Magnitude: 70.00 EG
Reported by: Broadcast Media

Delayed report of damage to a hay shed, loafing shed, and broken posts at the ground. Wind threw a 500 gallon tank about 100 yards. Winds estimated around 60-80 mph.

Thunderstorm Wind in OTTAWA, KANSAS
From 28-JUL-11 19:06:00 to 28-JUL-11 19:08:00 (CST-6)
Location: WELLS
Magnitude: 70.00 EG
Reported by: Emergency Manager

Multiple reports of wind damage in Ottawa County near the state lake. Windows blown out of a house near the intersection of N 180th Rd. and Limestone Rd. Three trees reported uprooted at the Ottawa County state lake. Three trees also reported down at the intersection of Kiowa Rd. and N 180th Rd. Barn reported mostly destroyed with pieces blown half a mile away at the intersection of Kiowa Rd. and N. 190th Rd.

Thunderstorm Wind in DICKINSON, KANSAS
From 29-JUL-11 15:01:00 to 29-JUL-11 15:02:00 (CST-6)
Location: HERINGTON
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Public estimates winds of 60 mph.

Thunderstorm Wind in MORRIS, KANSAS
From 29-JUL-11 15:09:00 to 29-JUL-11 15:10:00 (CST-6)
Location: DELAVAN
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Spotter estimates winds of 60 mph.

Thunderstorm Wind in GEARY, KANSAS
From 27-JUL-11 19:41:00 to 27-JUL-11 19:43:00 (CST-6)
Location: CAMP WHITSIDE
Magnitude: 70.00 EG
Reported by: Trained Spotter

Spotter estimates 80 mph winds with 18 inch elm tree limb blown down.

Thunderstorm Wind in GEARY, KANSAS
From 27-JUL-11 19:16:00 to 27-JUL-11 19:17:00 (CST-6)
Location: CAMP FORSYTHE
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Other Federal Agency

Estimate of 60 mph winds.

Thunderstorm Wind in RILEY, KANSAS
From 27-JUL-11 19:39:00 to 27-JUL-11 19:40:00 (CST-6)
Location: OGDEN
Magnitude: 52.00 EG
Reported by: Emergency Manager

Power lines down and tree damage on the south side of Ogden.

Thunderstorm Wind in RILEY, KANSAS
From 28-JUL-11 20:38:00 to 28-JUL-11 20:39:00 (CST-6)
Location: RANDOLPH
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Four inch diameter tree limbs blown out of maple tree.

Thunderstorm Wind in GEARY, KANSAS
From 27-JUL-11 19:50:00 to 27-JUL-11 19:52:00 (CST-6)
Location: (FRI)MARSHALL AAF FT
Magnitude: 52.00 EG
Reported by: Emergency Manager

Tree blocking hwy 177 south of interstate 70. Semi truck blown over on 177 2 miles south of interstate 70.