User:Cyclonebiskit/OKC2023

On April 19, 2023, an unusual series of supercell thunderstorms impacted the Oklahoma City metropolitan area. These slow-moving, cyclic storms produced a localized outbreak of 18 tornadoes and severe weather event that killed 3 people and injured 188 others. The storms were described as chaotic by meteorologists, with the cells exhibiting Fujiwhara interactions and mergers over the course of several hours.

Background and meteorological synopsis
Multiple days in advance, the Storm Prediction Center (SPC) highlighted the possibility for severe weather to develop throughout the central Great Plains, with weather models indicating the presence of a favorable environment for severe weather across Iowa, southeastern Nebraska, and central Kansas. All three of these states were given a Day 3 slight risk for severe weather, primarily focused on the hail threat. although the possibility of supercell development in the area was present, expected lapse rates favored more hail-producing storms. A marginal risk was issued for the Plains surrounding the slight risk area, extending into Wisconsin, and all the way to the Texas-Mexico border. The next day, on April 18, the SPC introduced a large 2% contour for tornadoes in the area, with a smaller 5% risk area centered in central Kansas, into southeastern Nebraska. A large, hatched corridor for large hail was established for most of the main risk area as well. The presence of elevated convective available potential energy (CAPE) values reaching into the 2,000–3000 J/kg range in an area with elevated upper level jet exit, and 50 to 60 F dew points in the region, made the environment unstable and favorable for supercell development. However, the presence of a capping inversion in the region, as well as rapid transition combined with the loss of diurnal daylight heating, was believed to be a limiting factor in the sustainment of more intense, rotating thunderstorms, hence the low tornado potential. By this time, the Oklahoma City metropolitan area was only covered under a 2% risk for tornadoes.

By April 19, the environment around central Oklahoma was showing signs of a more sustained environment for supercells capable of tornadoes, so a 5% corridor was introduced from the Oklahoma City metropolitan area southwestward into extreme northern Texas. Additionally, an enhanced risk for severe weather was introduced for an area encompassing northwestern Missouri, southwestern Iowa, southeastern Nebraska, and northeastern Kansas, due to the introduction of a hatched, 30% risk for large, destructive hail. Despite the elevated threat for tornadoes in south-central Oklahoma, the perceived lack of sufficient moisture was forecast to somewhat limit tornado potential, although it was noted that a conditional strong tornado threat did exist if any supercell could sustain itself. Later that afternoon, intense supercells developed south of Oklahoma City, with the leading one producing large hail and damaging winds, with a tornado also reported near Tinker Air Force Base. The trailing one would soon strengthen and become a prolific tornado producer, spawning 10 tornadoes, including several strong, large tornadoes, that moved along erratic paths due to the slow movement of the storm. The first strong tornado it dropped was an intense EF3 tornado that caused significant damage in Cole with a fatality occurring west of the town. Later, the supercell later spawned another large, high-end EF2 tornado near Etowah before absorbing merging with another tornadic supercell to its west; this cluster of storms spawned a large, broad mesocyclone that produced several circulations that rotated around each other due to the Fujiwhara effect. These circulation produced multiple additional large tornadoes touched down after sunset, including EF2 and EF3 tornadoes near Pink and a very large, destructive high-end EF2 tornado that struck Shawnee. Multiple PDS tornado warnings were issued as a result of this storm.

Impact
Three people were killed during the event, of which one was attributed to a tornado. Two of the deaths were in Cole and another occurred outside of McClain County but transported into the county. A total of 188 people were treated for storm-related injuries: 67 from falls, 28 from cuts, 28 from flying debris, 22 from transportation incidents, 14 from poisoning, 1 from burns, and 28 from various other causes.

According to Federal Emergency Management Agency (FEMA) surveys, a total of 2,124 homes were impacted by the severe weather event. Of these, 187 suffered minor damage, 161 sustained major damage, and 70 were destroyed. Earlier assessments from the Government of Oklahoma published on April 21 indicated at least 1,965 homes were impacted with 380–420 being severely damaged or destroyed. More than 90 percent of these structures were in Shawnee. The Oklahoma Department of Emergency Management and Homeland Security placed damage in excess of $9 million as of April 24. Damage to Shawnee Public Schools alone exceeded $20 million.

A total of 34,000 customers lost power at the height of the storm, predominantly in Shawnee where more than 600 power poles were snapped. Outages were reduced to 1,111 customers by April 25.

Aftermath
Within hours of the tornadoes, ten members of the Oklahoma Highway Patrol and personnel from Oklahoma City proper assisted with search and rescue in Cole. The Moore Emergency Management agency provided rescuers with lights. The Pottawattamie Emergency Management requested the establishment of a mobile command post from the Oklahoma Disaster Task Force and the Choctaw Nation. Oklahoma Task Force 1 (an urban search and rescue unit) was dispatched to Shawnee, with operations concluding by 6:30 p.m. on April 20. Technical rescue equipment was deployed to Shawnee to extract people trapped in a collapsed business.

The Red Cross opened three shelters: one in each of Noble, Shawnee, and Washington. The Salvation Army, Gordon Cooper Technology Center, and Regional Food Bank of Oklahoma provided meals to people in Bethel Acres, Cole, and Shawnee. The Oklahoma State Department of Health and Oklahoma Medical Reserve Corps provided tetanus shots beginning on April 21 at three locations in McClain County and two in Pottawattamie County. By April 21, two supply distribution centers were opened in Shawnee. The Convoy of Hope donated two tractor-trailers loaded with food, tarpaulins, and cleaning supplies. The Mennonite Disaster Services, Oklahoma Baptist Disaster Relief, and Samaritan’s Purse aided with cleanup, demolition, and repairs. The Southwest Incident Support Team, an agency tasked with assisting in disaster coordination, was dispatched to help with damage surveys. A volunteer center was opened by the Community Renewal of Pottawatomie County on April 22. Oklahoma Baptist University provided housing to displaced students. By April 26, all buildings except for Shawnee Hall at Oklahoma Baptist University were reopened. Shawnee High School suspended all in-person classes for the remainder of the school year, returning to virtual classes.

Oklahoma Governor Kevin Stitt declared a state of emergency for Cleveland, Lincoln, McClain, Oklahoma, and Pottawatomie counties on April 20. This activated the Emergency Price Stabilization Act, prohibiting price gouging during an emergency. President Joe Biden signed a federal disaster declaration for McClain and Pottawattamie counties on April 24. This enabled the distribution of federal funds for relief efforts. The Small Business Administration and Oklahoma Small Business Development Center opened a one-stop-shop recovery center in Shawnee on April 25 to aid businesses in their recovery process. Applications for Disaster Unemployment Assistance through the Oklahoma Employment Security Commission were made available beginning on May 4 with a deadline of June 5 for McClain and Pottawattamie residents and June 12 for Cleveland residents. Cleveland County was later added to the disaster declaration on May 8. By the same time, the FEMA had provided $920,000 to residents in McClain and Pottawattamie counties. The cost of debris cleanup in McClain and Pottawattamie counties was estimated in the millions. The United States Department of Agriculture's Food and Nutrition Service approved applications for Disaster Supplemental Nutrition Assistance Program benefits for residents in McClain and Pottawattamie counties based on their income and storm-related losses; applications would be accepted from May 8 to 12. Starting on May 15, grants up to $1,500 from the Oklahoma Housing Finance Agency were made available for victims whose homes were damaged. By May 31, total Individual Assistance costs from FEMA reached $5.47 million.