Tornado outbreak and floods of May 23–26, 2015

Preceded by more than a week of heavy rain, a slow-moving storm system dropped tremendous precipitation across much of Texas and Oklahoma during the nights of May 24–26, 2015, triggering record-breaking floods. Additionally, many areas reported tornado activity and lightning. Particularly hard hit were areas along the Blanco River in Hays County, Texas, where entire blocks of homes were leveled. On the morning of May 26, the National Weather Service issued a flash flood emergency for southwest Harris County (which includes the city of Houston) and northeast Fort Bend County. The system also produced deadly tornadoes in parts of Mexico, Texas, and Oklahoma. This flood significantly contributed to the wettest month ever for Texas and Oklahoma.July 2015 National Climate Report, NOAA

Meteorological synopsis

According to Bob Henson from Wunderground, inflow of low-level moisture from the Gulf of Mexico and the combination of very slow moving large-scale storm systems set the stage for the floods. He added,"Upper-level winds were largely aligned with the low-level frontal zone, an ideal setup for “thunderstorm training” (successive downpours over the same area). In addition, rains were concentrated by several mesoscale convective vortices, small-scale centers of low-pressure that developed along the frontal bands, in some cases resembling mini-tropical cyclones." The stationary trough during May is linked to both the El Niño and amplified midlatitude short-wave train.

The system also produced numerous tornadoes across the Great Plains on May 23 and 24. Most of these tornadoes were weak, though EF2 tornadoes caused considerable damage near New Boston, Illinois, and Ensign, Kansas. In Texas, EF1 tornadoes impacted mainly residential areas of Dallas, Houston, and Corpus Christi as well. In the early morning hours of May 25, a destructive tornado struck the Mexican border city of Ciudad Acuña, Coahuila; it was the first twister to strike the city in its history. Numerous cars and buses were thrown and mangled, and 750 properties were damaged or completely destroyed. Several masonry construction homes along the path were completely leveled. 14 fatalities occurred as a result, and an additional 229 residents were injured. The tornado was officially rated F3, though some sources list it as an F4. Additional tornadoes, a few of which were strong, touched down in Texas later throughout the day. This included an EF2 that killed one person near Cameron, Texas. Another EF2 tornado struck Henderson, causing considerable damage in town. In Oklahoma, an EF2 tornado caused heavy damage near the towns of Wister and Panama, while an EF3 tornado killed one person near Blue. Overall, the outbreak produced 75 tornadoes and killed 16 people, making it the deadliest North American tornado outbreak of 2015. This is the largest tornado outbreak in Central Texas history.Memorial Day storm brings deadly tornado outbreak, widespread floods, KXAN, June 9, 2015 Confirmed tornadoes

Note: One tornado in Mexico was rated F3 but is listed as EF3 in the above table.

May 23 event + List of confirmed tornadoes – Saturday, May 23, 2015EF#LocationCounty / ParishStateStart Coord.Time (UTC)Path lengthMax widthDamage(2015 USD) EF0WSW of BoslerAlbanyWY1855 – 1900$Tornado remained over open country, causing no damage. EF0N of PocassetGradyOK2212 – 2232$Four houses were damaged by this tornado. EF0N of Sulphur (1st tornado)MurrayOK2259 – 2307$Tornado damaged a workshop building. EF0SE of AdaPontotocOK2305$Brief tornado remained over open country, causing no damage. EF0N of Sulphur (2nd tornado)MurrayOK2310 – 2311$Brief tornado remained over open country, causing no damage. EF1E of BlanchardMcClainOK2311 – 2317$Ten homes were damaged by this large tornado. EF0S of StratfordGarvinOK2316$Brief tornado remained over open country, causing no damage. EF1NE of FrancisPontotoc, SeminoleOK2325 – 2333$Tornado caused significant tree damage along its path. EF0WSW of NewcastleMcClainOK2330 – 2332$Tornado remained over open country causing no damage. EF1SE of MaysvilleGarvinOK0005$A barn was destroyed by this brief tornado. EF0N of HoldenvilleHughesOK0013$Brief tornado remained over open country, causing no damage. EF1SSW of Balcones HeightsBexarTX0116 – 0117One home sustained major damage to its roof, and additional residences nearby sustained generally minor damage to their roofs and vehicles. A home's carport had its roof removed and displaced two blocks to the north. Trees were damaged. EF0SE of PanolaLatimerOK0144 – 0147$Large tree limbs were snapped by this weak tornado. EF0SE of Dripping SpringsHaysTX0153 – 0200Approximately 15 homes and numerous trees were damaged along the path. EF1NNW of JonestownTravisTX0158 – 0200A residence sustained roof and exterior wall damage as its front and back porches were destroyed. EF0HaysTravisTX0211 – 0213Significant tree damage and minor roof damage was observed in Hays. EF1N of Liberty HillWilliamsonTX0222 – 0234Damage was largely confined to large oak trees. Seven to ten homes sustained damage mainly to their roofs, the most substantial instance being the complete less of a chimney. A barn had part of its roof ripped off. EF0NE of JonestownTravis, WilliamsonTX0237 – 0238Damage to trees and a school occurred. EF1Wells BranchTravisTX0239 – 0242A business in town had its sheet metal roofing peeled back, and a stone brick sign was demolished. At an apartment complex, roofing shingles were damaged, large tree limbs were snapped, and a garbage dumpster was tossed. The second floor of a storage facility had its metal roof and walls collapsed. The tornado lifted and tossed 10 small moving trailers. Several power poles were blown over and additional tree limbs were snapped. EF1N of WyldwoodBastropTX0243 – 0244Several trees were uprooted, with several oaks sustaining substantial damage. Roof damage occurred at a residence. EF0WSW of AndiceWilliamsonTX0247Tree and minor roof damage occurred along the path. EF1NE of LeanderWilliamsonTX0247 – 0250Large tree limbs were snapped. Two homes sustained damage: one had a small portion of its roofing decking removed, while the second had over half of its roofing decking removed. Two large storage sheds were moved .

May 24 event + List of confirmed tornadoes – Sunday, May 24, 2015EF#LocationCounty / ParishStateStart Coord.Time (UTC)Path lengthMax widthDamage(2015 USD) EF1Western Corpus ChristiNuecesTX0627 – 0630$Numerous trees were snapped or uprooted, some of which fell on houses and vehicles. A flower nursery and a grocery store were damaged, and a baseball dugout was destroyed. Several residences sustained minor to moderate roof and siding damage as well. EF1Northern IrvingDallasTX0734 – 0736$Several trees, two high rise buildings, and several carports were damaged. EF1Northwestern DallasDallasTX0734 – 0737$Trees and power lines were damaged. An apartment complex and several warehouse buildings sustained roof damage. EF1Southwestern HoustonHarrisTX1133 – 1138$Ten structures at an apartment complex sustained roof damage, including one with complete roof removal and interior wall damage. A twelve-story glass facade building had several of its north-facing windows blown out. EF1S of MarshallHarrisonTX1634 – 1636$Trees were snapped or uprooted. A house sustained roof damage when its carport was lifted, a small outbuilding was destroyed, and a warehouse sustained roof damage. EF1E of MarshallHarrisonTX1646 – 1700Damage was largely confined to snapped or uprooted trees, some of which damaged structures and vehicles. EF1E of Lowry CitySt. ClairMO1715 – 1720Several outbuildings and two homes were severely damaged, and numerous trees were damaged or uprooted. EF1ESE of St. PaulLeeIA2242$A barn and a grain bin were destroyed, a couple of chimneys were damaged, and some trees and a power line were downed. EF0W of Merriman(1st tornado)CherryNE2245$Brief landspout tornado remained over open rangeland, causing no damage. EF0W of Merriman(2nd tornado)CherryNE2245$Law enforcement reported a brief landspout tornado in open rangeland. EF1W of TheodosiaOzarkMO2259 – 2308A tornado damaged or destroyed three barns, caused minor damage to a mobile home, and snapped or uprooted hundreds of trees. EF2N of New BostonMercerIL2350 – 0000$A large machine shed and two garages were completely destroyed, and a house had a portion of its roof ripped off. Additional trees and outbuildings were damaged. EF1NNE of Kismet to N of PlainsSeward, MeadeKS0237 – 0321$Irrigation pivots were damaged by this large wedge tornado. EF0W of HayneSewardKS0247 – 0249$Tornado remained over open country causing no damage. EF0NE of PlainsMeadeKS0306 – 0314$Tornado remained over open country, causing no damage. EF0N of PlainsMeadeKS0320 – 0334$Tornado remained over open country, causing no damage. EF1NNE of Plains to SE of MontezumaMeade, GrayKS0347 – 0430Numerous pivot irrigation sprinklers were damaged by this large wedge tornado. EF2SW of Dodge CityMeade, FordKS0426 – 0515High voltage transmission lines and poles, pivot irrigation sprinklers, trees, and a home were damaged by this large wedge tornado. The home had a large stock trailer thrown into it. A car was tossed to the northeast.

May 25 event