1965 Kokomo tornado

On April 9, 1965, a prominent central upper trough moved eastward toward the Central United States, with a lead upper low pivoting over the Dakotas and Upper Midwest region. A Southern stream shortwave trough and a moderately strong polar jet moved east-northeastward over the southern Rockies to the southern Great Plains and Ozarks area, with severe thunderstorms forming during the peak hours of heating. With the influence of moderately strong cyclonic flow aloft, the air mass was expected to become unstable across much of the southern Great Plains, Ozarks and middle Mississippi Valley by the afternoon.

Evidence of an unstable air mass included temperatures in the low to mid 80s °F (27–30 °C), dewpoints that ranged in the upper 60s °F (20 °C) to lower 70s °F (20–22 °C), and CAPE values ranging from 3500–5000 J/kg. Deep-layer wind shear speeds of 40 to 50 knots (46 to 58 mph) would enhance storm organization and intensity. These ingredients were present ahead of a cold front extending from a surface low in the eastern Dakotas, southwestward and western Missouri, and ahead of a dry line extending from southwest Iowa southward into western north and west-central Illinois. Outflow remnants from the previous night and early day convection across the Ozarks and middle Mississippi Valley were a factor in severe weather development with the most aggressive heating and destabilization on the western edge of this activity across the southern Great Plains and just ahead of a cold front. The National Weather Service office in Norman, Oklahoma, had warned as early as April 8 that there was a possibility of severe weather on April 11.

The most intense severe weather activity was expected across the southern Great Plains, specifically, during the afternoon hours on that Monday. The degree of wind shear, moisture and instability within the warm sector favored the development of supercells. Very large hail and tornadoes were expected with the supercells, with the possibility of a few strong tornadoes. The National Weather Service issued a tornado watch at 1:10 p.m. Central Daylight Time (CDT) early that afternoon for the Mississippi, Ohio, and Great Lakes Region, northwestern Iowa and portions of Wisconsin.[2]

The thunderstorm that eventually produced the tornado developed, around 6:30 p.m. CDT, across northern Tippecanoe County. Its rapid intensification resulted in the National Weather Service Weather Forecast Office in Norman issuing a severe thunderstorm warning for northern Tippecanoe, Howard County, northern Clinton, ) at 7:14 p.m. CDT. The thunderstorm quickly attained supercell characteristics, with rotation at the mid-levels of the storm's cloud structure becoming apparent even before it was officially classified as severe, due to the sufficient amounts of wind shear present over central Indiana

Due to the expected intensity of the storms, which were expected to be equal – if not, stronger – in severity to the supercells that produced the five tornadoes in the expected area of greatest tornadic threat the day prior. At 7:30 p.m. CDT, as rotation in the supercell was increasing at the cloud base, a tornado warning was issued for far northeastern Grant, Howard, and Clinton counties, as the storm approached Russiaville.

The tornado touched down at 7:32 p.m. CDT in northeastern Clinton county. Initially a narrow, cone-shaped tornado, it first caused F1 damage to a home and some trees before rapidly intensifying. As the tornado entered Alto, several homes were destroyed, two of which were leveled at F4 intensity. At this point, the tornado began to grow rapidly in size, evolving into a large, wedge-shaped structure; slight ground scouring began in this area. Several homes in a subdivision further to the northeast sustained F3 damage. By 7:44 p.m. CDT, the supercell also produced straight-line winds of 80 miles per hour (130 km/h) for at least one mile surrounding the tornadic circulation.

The tornado maintained F3 intensity as it crossed the into the southern part of Kokomo. The tornado then continued in Kokomo, roughly following Lincoln St. At that point, it began to grow rapidly in width, and a second brief area of F4 damage was noted near South May Avenue, where several homes were leveled, and one was swept away from its foundation (this home was determined to have been nailed, rather than bolted to its foundation). A vehicle frame, engine block, and various other vehicle parts were found tangled within a grove of completely debarked trees in this area. As the tornado began to cross Greentown, a traffic jam had occurred for a stretch of several miles along Washington Avenue. The tornado weakened briefly to an F3 before re-intensifying to F4 intensity near Forman Drive, flattening several homes as it moved through mostly rural areas south of Southwest 31. As the tornado struck a Chrysler plant, the east and west sides of the wall were leveled.

The tornado maintained its intensity as it struck the Orr Family Farm and the Celestial Acres horse training area, where up to 100 horses were reported killed, some being tossed into and tangled in downed power lines or thrown on top of nearby buildings; several horses that survived the tornado suffered severe injuries, with some being impaled by tree limbs or boards. Every building at the Delco area sustained F4 damage, along with a nearby strip mall. A 10-ton propane tank on the Orr Farm property was picked up and thrown more than a half-mile through the air by the tornado. The tornado continued east, heavily scouring an open field before intensifying even further and slamming into Greentown, which was completely destroyed at F5 intensity. (though a 2014 study published by the American Meteorological Society revealed evidence of poor construction at the town, and the F5 rating at that location was downgraded to F4) Two 12,000-gallon water tanks that were also swept off the Orr Family Farm grounds were thrown into this area.

As the tornado was approaching Marion, the tornado weakened to F3 intensity and destroyed parts of the north side of town. The tornado then weakened as it stayed over an open field and finally lifted in the air at 8:17 P.M.[3]

The Indiana Department of Emergency Management reported that 17 people were killed (with another death indirectly attributed to the tornado). An estimated 1,150 homes were destroyed, resulting in an estimated $250 million in damages. The number of injured was 560. Entire subdivisions were obliterated, and houses were flattened in a large swath of the city. The majority of a neighborhood just west of the Moore Medical Center was destroyed. Witnesses said the tornado more closely resembled "a giant black wall of destruction" than a typical twister.

The Maple Crest School was heavily damaged, but no one present in the building was injured by the tornado. Part of US 31 was shut down due to debris that had been thrown onto the freeway. On April 12, Kokomo still did not have running water. There were more than 15,500 power outages related to the tornado. More than 100 people were rescued from areas that sustained significant damage from the tornado.[4]

On April 12, cleanup began on the city. They began working on restoring water and electricity to residents. After that, they began cleanup. Many residents began rebuilding after their properties were cleaned. Total estimates the damage to have surpassed 250 million dollars. This was the deadliest tornado in Howard County.

• 1965 Palm Sunday tornado outbreak