Storms formed along a cold front during the afternoon of the 21st, eventually forming a line. Through the evening storms swept eastward through Oklahoma and western north Texas. Significant hail, severe winds, and a few short-lived tornadoes as well as some minor flooding were reported with these storms.

Hail in KIOWA, OKLAHOMA
From 21-OCT-17 15:20:00 to 21-OCT-17 15:20:00 (CST-6)
Location: ROOSEVELT
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: COOP Observer

Hail in TILLMAN, OKLAHOMA
From 21-OCT-17 15:40:00 to 21-OCT-17 15:40:00 (CST-6)
Location: FREDERICK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in JACKSON, OKLAHOMA
From 21-OCT-17 15:57:00 to 21-OCT-17 15:57:00 (CST-6)
Location: HEADRICK
Magnitude: 3.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Fire Department/Rescue

Hail in JACKSON, OKLAHOMA
From 21-OCT-17 16:03:00 to 21-OCT-17 16:03:00 (CST-6)
Location: HEADRICK
Magnitude: 1.75 
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Windshield damage was reported.

Hail in BECKHAM, OKLAHOMA
From 21-OCT-17 16:10:00 to 21-OCT-17 16:10:00 (CST-6)
Location: SAYRE
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in TILLMAN, OKLAHOMA
From 21-OCT-17 16:14:00 to 21-OCT-17 16:14:00 (CST-6)
Location: MANITOU
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in TILLMAN, OKLAHOMA
From 21-OCT-17 16:20:00 to 21-OCT-17 16:20:00 (CST-6)
Location: MANITOU
Magnitude: 2.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Hail in BECKHAM, OKLAHOMA
From 21-OCT-17 16:25:00 to 21-OCT-17 16:25:00 (CST-6)
Location: ELK CITY
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Hail in STEPHENS, OKLAHOMA
From 21-OCT-17 20:11:00 to 21-OCT-17 20:11:00 (CST-6)
Location: DUNCAN
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in BRYAN, OKLAHOMA
From 21-OCT-17 22:40:00 to 21-OCT-17 22:40:00 (CST-6)
Location: COLBERT
Magnitude: 57.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Twelve inch diameter tree was downed.

Hail in COMANCHE, OKLAHOMA
From 21-OCT-17 17:00:00 to 21-OCT-17 17:00:00 (CST-6)
Location: INDIAHOMA
Magnitude: 3.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Location is approximate.

Hail in JACKSON, OKLAHOMA
From 21-OCT-17 16:28:00 to 21-OCT-17 16:28:00 (CST-6)
Location: HEADRICK
Magnitude: 2.75 
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Roof damage and broken windshield damage was reported.

Hail in ALFALFA, OKLAHOMA
From 21-OCT-17 16:29:00 to 21-OCT-17 16:29:00 (CST-6)
Location: GOLTRY
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Flash Flood in GRADY, OKLAHOMA
From 21-OCT-17 19:12:00 to 21-OCT-17 22:12:00 (CST-6)
Location: CHICKASHA ARPT
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

About a foot of water was over the roads.

Thunderstorm Wind in COMANCHE, OKLAHOMA
From 21-OCT-17 17:10:00 to 21-OCT-17 17:10:00 (CST-6)
Location: CACHE
Magnitude: 52.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Powerpoles partially blown down. Time estimated by radar.

Hail in COMANCHE, OKLAHOMA
From 21-OCT-17 17:20:00 to 21-OCT-17 17:20:00 (CST-6)
Location: MT SCOTT
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in KIOWA, OKLAHOMA
From 21-OCT-17 17:43:00 to 21-OCT-17 17:43:00 (CST-6)
Location: MOUNTAIN PARK
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Employee

Thunderstorm Wind in CADDO, OKLAHOMA
From 21-OCT-17 18:15:00 to 21-OCT-17 18:15:00 (CST-6)
Location: STECKER
Magnitude: 53.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Mesonet

Tornado in TILLMAN, OKLAHOMA
From 21-OCT-17 16:23:00 to 21-OCT-17 16:23:00 (CST-6)
Location: MANITOU
Tornado F-scale: EFU
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Numerous storm chasers observed and reported a brief landspout estimated to have occurred about 3 miles southeast of Manitou. No damage was reported.

Tornado in COMANCHE, OKLAHOMA
From 21-OCT-17 17:05:00 to 21-OCT-17 17:05:00 (CST-6)
Location: INDIAHOMA
Tornado F-scale: EFU
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Media coverage showed a brief tornado approximately 2 miles east of Indiahoma. No damage was reported.

Thunderstorm Wind in POTTAWATOMIE, OKLAHOMA
From 21-OCT-17 20:32:00 to 21-OCT-17 20:32:00 (CST-6)
Location: BROOKSVILLE
Magnitude: 78.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Metal shed destroyed by wind.

Hail in CLEVELAND, OKLAHOMA
From 21-OCT-17 19:50:00 to 21-OCT-17 19:50:00 (CST-6)
Location: MOORE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Hail in OKLAHOMA, OKLAHOMA
From 21-OCT-17 19:50:00 to 21-OCT-17 19:50:00 (CST-6)
Location: (OKC)WILL ROGERS APT
Magnitude: 1.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Public

Hail in CLEVELAND, OKLAHOMA
From 21-OCT-17 19:52:00 to 21-OCT-17 19:52:00 (CST-6)
Location: MOORE
Magnitude: 1.50 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Thunderstorm Wind in STEPHENS, OKLAHOMA
From 21-OCT-17 19:54:00 to 21-OCT-17 19:54:00 (CST-6)
Location: DUNCAN
Magnitude: 50.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in OKLAHOMA, OKLAHOMA
From 21-OCT-17 19:55:00 to 21-OCT-17 19:55:00 (CST-6)
Location: DEL CITY
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Hail in OKLAHOMA, OKLAHOMA
From 21-OCT-17 20:02:00 to 21-OCT-17 20:02:00 (CST-6)
Location: (TIK)TINKER AFB
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Thunderstorm Wind in GRADY, OKLAHOMA
From 21-OCT-17 19:14:00 to 21-OCT-17 19:14:00 (CST-6)
Location: BRIDGE CREEK
Magnitude: 52.00 EG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

No damage reported.

Hail in GRADY, OKLAHOMA
From 21-OCT-17 19:27:00 to 21-OCT-17 19:27:00 (CST-6)
Location: BRIDGE CREEK
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in GRADY, OKLAHOMA
From 21-OCT-17 19:30:00 to 21-OCT-17 19:30:00 (CST-6)
Location: BRIDGE CREEK
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Thunderstorm Wind in GRADY, OKLAHOMA
From 21-OCT-17 19:30:00 to 21-OCT-17 19:30:00 (CST-6)
Location: BRIDGE CREEK
Magnitude: 56.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Sheet metal debris blown onto side roadway off of Highway 4, south of Fox Lane and to the west.  Time estimated by radar.

Flash Flood in PAYNE, OKLAHOMA
From 21-OCT-17 19:44:00 to 21-OCT-17 22:44:00 (CST-6)
Location: STILLWATER
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Street flooding reported with stalled vehicles.

Hail in CLEVELAND, OKLAHOMA
From 21-OCT-17 19:45:00 to 21-OCT-17 19:45:00 (CST-6)
Location: MOORE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Hail in CLEVELAND, OKLAHOMA
From 21-OCT-17 19:47:00 to 21-OCT-17 19:47:00 (CST-6)
Location: MOORE
Magnitude: 1.00 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Hail in STEPHENS, OKLAHOMA
From 21-OCT-17 20:08:00 to 21-OCT-17 20:08:00 (CST-6)
Location: DUNCAN
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Hail in GRADY, OKLAHOMA
From 21-OCT-17 18:45:00 to 21-OCT-17 18:45:00 (CST-6)
Location: CHICKASHA ARPT
Magnitude: 0.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio

Lightning in CLEVELAND, OKLAHOMA
From 22-OCT-17 00:00:00 to 22-OCT-17 00:00:00 (CST-6)
Location: (OUN)NORMAN WESTHEIMER ARPT
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Public

A branch 6-8 inches in diameter fell onto a roof. Time is a rough estimate from source. Photo shows evidence of lightning charring (and wind damage is unlikely for the time estimate given).

Tornado in MCCLAIN, OKLAHOMA
From 21-OCT-17 19:36:00 to 21-OCT-17 19:40:00 (CST-6)
Location: GOLDSBY
Tornado F-scale: EF1
Property damage: 100.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado developed just north of State Highway 9 and just west of Santa Fe Avenue where tree damage was noted. The tornado moved east damaging a business and destroying a shed along Highway 9.  The tornado turned southeast crossing Highway 9 and passed near the Riverwind Casino and Hotel along with strong winds on the south flank of the tornado. Trees were snapped just west of the casino. At the casino, two air conditioner units were displaced from their pedestal on the roof of the building, which allowed rain inside the structure. Some roof facade damage was also noted at the casino. Just south at the adjacent hotel, strong winds created some roof facade and siding damage (see adjacent Thunderstorm Wind Entry).
The tornado crossed Interstate 35 and damaged businesses and destroyed at least one shed between the interstate and the Canadian River before moving into inaccessible areas near the river and crossing into Cleveland County south of Norman.

Thunderstorm Wind in MCCLAIN, OKLAHOMA
From 21-OCT-17 19:37:00 to 21-OCT-17 19:40:00 (CST-6)
Location: GOLDSBY
Magnitude: 78.00 EG
Property damage: 10.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Immediately south of the tornado that moved near State Highway 9, a large area of damaging winds, likely associated with the Rear Flank Downdraft, produced additional damage from near Riverwind Casino and Hotel to the Canadian River. Just east of Interstate 35, this area of damaging winds was it's widest at around 500 yards. Roof facade was pulled from the Riverwind Hotel, which damaged the hotel siding and broke a first story window as it fell. Numerous trees were damaged east of Interstate 35 but south of the tornado path with damage consistent with winds of approximately 90 mph.

Tornado in CLEVELAND, OKLAHOMA
From 21-OCT-17 19:40:00 to 21-OCT-17 19:42:00 (CST-6)
Location: NORMAN
Tornado F-scale: EF0
Property damage: 2.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

The tornado moved into Cleveland County in inaccessible areas along the Canadian River and generally remained south of the neighborhoods in south Norman south of Highway 9. Some tree and fence damage was observed at the southern end of South Canadian Trails which is where the tornado is believed to have dissipated.

Tornado in SEMINOLE, OKLAHOMA
From 21-OCT-17 20:52:00 to 21-OCT-17 20:55:00 (CST-6)
Location: SEMINOLE
Tornado F-scale: EF1
Property damage: 50.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado developed on the northwest side of Seminole near the U.S. Highway 270 and Reid Street, and move southeast through town dissipating near U.S. Highway 270 and 7th Street. Most of the damage was tree damage with many trees snapped or uprooted, especially in the Maple Grove Cemetery on the northwest side of town. However, a few homes and other buildings also received roof damage including one home where much of the roof was pulled off. One family was trapped in their storm cellar when a tree fell on the cellar door. Near downtown, a church received roof damage and portions of the roof were impaled in the siding of nearby businesses.

Hail in JACKSON, OKLAHOMA
From 21-OCT-17 16:12:00 to 21-OCT-17 16:12:00 (CST-6)
Location: HEADRICK
Magnitude: 2.75 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Trained Spotter

One hail injury was reported.

Tornado in CADDO, OKLAHOMA
From 21-OCT-17 18:12:00 to 21-OCT-17 18:13:00 (CST-6)
Location: CYRIL
Tornado F-scale: EF1
Property damage: 5.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado snapped trees and produced roof damage to a home near the intersection of County Roads 2660 and 1440.

Tornado in CADDO, OKLAHOMA
From 21-OCT-17 18:08:00 to 21-OCT-17 18:16:00 (CST-6)
Location: CYRIL
Tornado F-scale: EF1
Property damage: 3.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

The first of series of tornadoes in Caddo County was observed to develop just south of State Highway 19, 4 miles west of Cyril. Trees were damaged just south of Highway 19 as the tornado moved northeast, and trees were snapped after crossing County Road 2660. Storm chasers observed the tornado cross near or just north of the intersection of County Roads 1440 and 2680 moving ENE before dissipating just before crossing State Highway 8.

Tornado in CADDO, OKLAHOMA
From 21-OCT-17 18:12:00 to 21-OCT-17 18:24:00 (CST-6)
Location: CYRIL
Tornado F-scale: EF1
Property damage: 15.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado took a 6 mile path through Caddo County northwest of Cyril and Cement. Damage was confined to snapped or uprooted trees along the path.

Tornado in CADDO, OKLAHOMA
From 21-OCT-17 18:16:00 to 21-OCT-17 18:21:00 (CST-6)
Location: STECKER
Tornado F-scale: EF1
Property damage: 10.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado developed just west of County Road 2660 near County Road 1420 and moved northeast. Barns were significantly damaged along County Road 2660 and another along State Highway 8. Trees were snapped along the entire path. The tornado moved northeast to near County Road 1400 east of State Highway 8, and then turned east-southeast and dissipated soon after snapping more trees along County Road 2680.

Tornado in CADDO, OKLAHOMA
From 21-OCT-17 18:23:00 to 21-OCT-17 18:28:00 (CST-6)
Location: CEMENT
Tornado F-scale: EF1
Property damage: 3.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

Trees were snapped near the intersection of County Roads 1410 and 2720, and again along County Road 1400 just a few hundred yards west of the Caddo-Grady County line. No damage was noted along or east of the county line in Grady County.

Hail in GRADY, OKLAHOMA
From 21-OCT-17 19:30:00 to 21-OCT-17 19:30:00 (CST-6)
Location: TABLER
Magnitude: 0.88 
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Amateur Radio