Jarrell tornado
In the afternoon hours of May 27, 1997, a large, slow-moving and exceptionally intense F5 tornado caused extreme damage across portions of the Jarrell, Texas area. Known most frequently as the Jarrell tornado, it killed 27 residents in the Double Creek Estates, which at the time was a small subdivision located to the northwest of Jarrell, and inflicted approximately in damages during its 13-minute, track. It occurred as part of a tornado outbreak across central Texas; it was produced by a supercell that had developed from an unstable airmass and favorable meteorological conditions at the time, including very high convective available potential energy values and warm dewpoints.
Several weaker tornadoes prior to the Jarrell tornado touched down and inflicted damage in nearby areas, particularly in Travis and Williamson counties. The National Weather Service office in Fort Worth issued several tornado warnings as a result, and later issued a tornado warning for the area encompassing Jarrell as the tornado-producing supercell approached the town. Shortly thereafter, within the Williamson County line, the tornado first touched down as a landspout before it transitioned into a larger multi-vortex tornado cloaked in dust. The landspout merged with the parent storm’s mesocyclone, becoming a violent mesocyclonic tornado, which then strengthened rapidly as its width grew. As the tornado moved through a neighborhood near Jarrell, it slowed down over the area while reaching its maximum width and producing violent F5-level winds. The tornado slowly moved over the neighborhood for approximately 3 minutes, producing some of the most extreme tornadic wind damage ever recorded. As the tornado left the subdivision, it began to weaken, before dissipating in a forested area. In total, 27 residents of Jarrell, as well as hundreds of cattle, were killed. The tornado left behind a path of devastation, including many houses and buildings that were swept clean from their foundations.
, this tornado is Texas' most recent F5 or EF5 tornado. The tornado was the fourth-deadliest of the 1990s in the United States, only being surpassed by the 1990 Plainfield tornado that killed 29, the 1998 Oak Grove-Birmingham tornado that killed 32, and the 1999 Bridge Creek–Moore tornado that killed 36. It was the only F5 tornado of 1997.
Meteorological synopsis
On the morning of May 27, 1997, an upper-level low-pressure area located over portions of South Dakota and Nebraska had moved northward which caused a weak, mid-level flow across Texas. While this occurred, a cold front extended southwest of a surface-based low-pressure area from Fayetteville, Arkansas to the Dallas–Fort Worth metroplex to the Permian Basin, which also included two decaying outflow boundaries northeast of the DFW metroplex. A gravity wave was also noted from the cold front near Waco, Texas and southward, which would promote initiation of supercells, including the one which produced the Jarrell tornado. The latter two factors were caused by an overnight mesoscale convective system which had dissipated before the mesoscale setup of the Jarrell tornado.An upper-air balloon sounding was conducted by the National Weather Service in Fort Worth while the cold front passed directly over the DFW metroplex, which showed favorable mid-level lapse rates, a dewpoint temperature of on the surface, and some wind shear, though not towards the surface, which suggested non-tornadic supercell activity. However, a sounding launched from Calvert, Texas a few hours later revealed surface-based CAPE values above 6500 J/kg, up from 3000 J/kg shown by the sounding previously launched over the DFW metroplex. This, along with extremely high CAPE values shown near the surface from a sounding over Waco at 12:00 CDT, likely caused vorticity near and along the cold front and the production of the Jarrell tornado.
The supercell that produced the Jarrell tornado first developed in McLennan County before noon, initially moving slowly southwestward in the unstable airmass. Shortly thereafter, a tornado watch was issued by the Storm Prediction Center for eastern Texas and western Louisiana. As the thunderstorm cell moved parallel to Interstate 35, it rapidly intensified and prompted the issuance of a severe thunderstorm warning for portions of McLennan County at 12:50 CDT, later being upgraded to a tornado warning as the supercell then began to rapidly exhibit lower-levels of rotation. This would result in multiple tornadoes being produced before the Jarrell tornado occurred; most notably an F3 tornado which caused severe damage in portions of Falls County near Bruceville-Eddy and Lake Belton. Another tornado, rated an F0, touched down near Stillhouse Dam and was incorrectly claimed as the Jarrell tornado due to its close proximity from the F5 tornado's path.
Shortly thereafter, the supercell began to move slightly westward towards Jarrell and Salado while continuing to show signs of rapid, low-level rotation. This would result in another tornado warning being issued by the National Weather Service in Austin/San Antonio for Williamson County, including Jarrell, at 15:30 CDT, in response to the storm's approach to the town. The warning was in effect for a duration of one hour, and local warning sirens in the town went off an estimated 10–12 minutes before the impact. Multiple short-lived, small, and rope-like funnel clouds preceded the Jarrell tornado; and despite being theorized and commonly accepted as being separate tornadoes, there is a possibility that these were part of it. Additionally, some reports stated an F1 tornado near Prairie Dell as an earlier continuation of this tornado.
Tornado summary
The tornado officially touched down within the Williamson County line north of Jarrell as a narrow rope landspout tornado at 3:40 pm CDT. The tornado began to undergo a rapid intensification as it attached itself to the mesocyclone within the parent supercell. It quickly transitioned from a landspout to a powerful mesocyclonic tornado, and began to morph and widen, taking on a large multi-vortex structure. Traffic along Interstate 35 came to a stop as the tornado came into view nearby; the Texas Highway Patrol also stopped traffic on both sides of the interstate under the expectation that the tornado would cross the highway. However, it instead moved parallel to Interstate 35 without impacting the roadway.Tracking south-southwest, the tornado quickly intensified and grew in width, becoming large and violent. The exact size of the tornado was difficult to determine during this portion of the tornado's life. Its intense winds scoured the ground, shredded vegetation, and stripped pavement from three county roads; the thickness of the asphalt pavement was estimated to be. A culvert plant near the intersection of two county roads collapsed. Nearby, a similar plant and a mobile home sustained some damage, with the latter struck by a 2×4
The tornado turned slightly around 3:48 pm, entering the Double Creek Estates at violent F5 intensity. It grew to its maximum width, estimated to be. Post-event surveys and eyewitness accounts reported that the tornado began to slow its forward movement. The tornado immediately began to destroy structures and homes as it hit multiple streets at the northeastern edge of the housing development. A recovered clock and synced videos marked the start of the tornado's impact on the subdivision at 3:48 pm. The entirety of Double Creek Estates was subject to extreme winds for three minutes due to the slow forward movement of the tornado. All homes on Double Creek Drive and in other parts of the subdivision, some well-built and properly bolted, were completely swept away, leaving only bare concrete foundation slabs behind, and the remaining foundations of several homes in the direct path of the tornado had their plumbing and sill plates ripped away. In the hardest hit areas of Double Creek Estates, homes were so thoroughly obliterated that there was virtually no recoverable debris left behind, and what debris was left had been finely granulated into small fragments and dispersed over a wide area. Grass was completely scoured from lawns throughout the neighborhood, and nearby grassy fields also sustained extreme ground scouring of up to in depth, leaving behind a wide swath of mud and bare soil.
As a result of this, the tornado's damage path was heavily studied due to its visibility from the extensive ground scouring. Additionally, the tornado lifted and threw numerous vehicles at Double Creek Estates, which were either mangled beyond recognition or torn apart. At least six hardly recognizable cars were found over away, completely crushed and left caked in mud and scoured grass. Several other vehicles were never recovered, and are presumed to have been torn into numerous pieces inside the tornado. Trees of all sizes in the subdivision were completely debarked, with one small tree documented to have had an electrical cord pierced through its trunk. There were 38 structures in Double Creek Estates that were destroyed; three businesses adjacent to the neighborhood were also completely demolished. In total, the tornado dealt $10–20 million in damage to Double Creek Estates.
After exiting the Double Creek Estates area, the tornado then crossed over a county road while paralleling Spears Ranch Road. The damage in these outlying areas was sporadic: in one case, a mobile home suffered only minor damage while an nearby house lost its roof and several exterior walls. The road's guardrail was impaled by wooden planks. After continuing into a cedar tree forest, it began to rapidly weaken, crossing over Appaloosa Cove Road before dissipating. The National Centers for Environmental Information concluded that it had lifted at 3:53 pm, remaining on the ground for 13 minutes and traversing.