Strong to severe thunderstorms moved through eastern Oklahoma during the morning of the 28th. These storms produced locally heavy rainfall that resulted in flash flooding, damaging wind gusts, and three tornadoes. Another round of thunderstorms developed across eastern Oklahoma during the evening of the 28th, as a cold front moved into the area. The strongest storms produced damaging wind.
Widespread heavy rainfall of four to six inches, with isolated amounts to eight inches, resulted in significant rises on rivers in eastern Oklahoma. Major flooding occurred along the Illinois River, with moderate flooding along the Poteau River.

Flood in ADAIR, OKLAHOMA
From 28-APR-21 16:15:00 to 30-APR-21 06:00:00 (CST-6)
Location: CHEWEY
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The Illinois River near Chewey rose above its flood stage of 12 feet at 5:15 pm CDT on April 28th. The river crested at 22.33 feet 3:45 am CDT on the 29th, resulting in major flooding. The crest was the fifth highest crest ever recorded at this site. Very severe flooding occurred from near Fidler's Bent to near Hanging Rock, with numerous cabins flooded in permanent campgrounds, and portions of Chewey Road were inundated east of Chewey Bridge. Monetary damage from this flood is unknown. The river fell below flood stage at 7:00 am CDT on the 30th.

Flood in CHEROKEE, OKLAHOMA
From 28-APR-21 22:30:00 to 30-APR-21 21:30:00 (CST-6)
Location: TAHLEQUAH
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The Illinois River near Tahlequah rose above its flood stage of 11 feet at 11:30 pm CDT on April 28th. The river crested at 21.82 feet at 3:00 pm CDT on the 29th, resulting in major flooding. Severe flooding occurred from near Hanging Rock to near Tahlequah where cabins and parks were severely flooded, and portions of Highway 10 were impassable. Monetary damage from this flood is unknown. The river fell below flood stage at 10:30 pm CDT on the 30th.

Flood in LE FLORE, OKLAHOMA
From 29-APR-21 04:15:00 to 30-APR-21 23:59:00 (CST-6)
Location: PANCO
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The Poteau River near Panama rose above its flood stage of 29 feet at 5:15 am CDT on April 29th. The river crested at 36.25 feet at 5:30 am CDT on the 30th, resulting in moderate flooding. Agricultural land was flooded from near Panama to near Arkoma, and county roads were closed. The river remained above flood stage through the end of April, and fell below flood stage at 6:30 pm CDT on May 1st.

Flood in ADAIR, OKLAHOMA
From 28-APR-21 09:30:00 to 30-APR-21 00:15:00 (CST-6)
Location: WATTS
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Official NWS Observations

The Illinois River near Watts rose above its flood stage of 13 feet at 10:30 am CDT on April 28th. The river crested at 23.97 feet at 8:00 pm CDT on the 28th, resulting in major flooding. Very severe flooding occurred from the Arkansas border to Fidler's Bend. Permanent buildings and cabins were flooded to a depth of several feet. Monetary damage from this flood is unknown. The river fell below flood stage at 1:15 am CDT on the 30th.

Tornado in ADAIR, OKLAHOMA
From 28-APR-21 05:01:00 to 28-APR-21 05:04:00 (CST-6)
Location: BIDDING SPGS
Tornado F-scale: EFU
Property damage: 0.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado produced a tornadic debris signature on the KSRX WSR-88D that lasted at least three minutes. The survey team could not access the heavily wooded area where this tornado likely occurred due to the lack of roads transecting the path.

Flash Flood in ADAIR, OKLAHOMA
From 28-APR-21 06:09:00 to 28-APR-21 10:45:00 (CST-6)
Location: WESTVILLE
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Social Media

Roads were flooded in and around Westville.

Flash Flood in SEQUOYAH, OKLAHOMA
From 28-APR-21 10:00:00 to 28-APR-21 13:45:00 (CST-6)
Location: VIAN
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Numerous roads were flooded in and around Vian.

Flash Flood in MCINTOSH, OKLAHOMA
From 28-APR-21 10:30:00 to 28-APR-21 13:45:00 (CST-6)
Location: EUFAULA
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Broadcast Media

Portions of Highway 9 were flooded west of Eufaula.

Flash Flood in DELAWARE, OKLAHOMA
From 28-APR-21 13:39:00 to 28-APR-21 20:30:00 (CST-6)
Location: LEACH
Flood cause: Heavy Rain
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Portions of Highway 412 were closed between Leach and Kansas due to flooding.

Thunderstorm Wind in LE FLORE, OKLAHOMA
From 28-APR-21 20:21:00 to 28-APR-21 20:21:00 (CST-6)
Location: ROCK IS
Magnitude: 63.00 MG
Property damage: 0.00K
Crop damage: 0.00K
Reported by: Storm Chaser

Thunderstorm wind gusts were measured to 73 mph by a storm chaser.

Tornado in ADAIR, OKLAHOMA
From 28-APR-21 05:06:00 to 28-APR-21 05:19:00 (CST-6)
Location: STILWELL
Tornado F-scale: EF1
Property damage: 50.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado damaged a home, destroyed a couple outbuildings, damaged chicken houses, and uprooted trees. Based on this damage, maximum estimated wind in the tornado was 90 to 100 mph.

Tornado in PITTSBURG, OKLAHOMA
From 28-APR-21 09:57:00 to 28-APR-21 10:09:00 (CST-6)
Location: MC ALESTER SANDERS F
Tornado F-scale: EF1
Property damage: 25.00K
Crop damage: 0.00K
Reported by: NWS Storm Survey

This tornado damaged a home, destroyed an outbuilding, and snapped or uprooted numerous trees. Based on this damage, maximum estimated wind in the tornado was 95 to 105 mph.

Thunderstorm Wind in CHOCTAW, OKLAHOMA
From 28-APR-21 22:58:00 to 28-APR-21 22:58:00 (CST-6)
Location: SAWYER
Magnitude: 65.00 EG
Property damage: 2.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Strong thunderstorm wind blew down trees near Sawyer, with some trees falling onto roads. Power lines were also blown down in the area.