From April 9–11, 1947, a significant tornado outbreak produced catastrophic effects over portions of the southern Great Plains, in the contiguous United States. The outbreak generated at least 12, and possibly 17 or more, tornadoes, many of which were significant. On Wednesday, April 9, a series of related tornadoes spawned by a single supercell, dubbed the Glazier–Higgins–Woodward tornadoes, swept through the U.S. states of Texas, Oklahoma, and Kansas. Most of the damage and nearly all of the deaths are still blamed on one large tornado, known as the Glazier–Higgins–Woodward tornado, that traveled from Texas to Oklahoma, beginning over the South Plains. This event, up to nearly in width, was often compared to the Tri-State tornado, because it was originally thought to have left a path, was similarly large and intense for much of its path, and was also retroactively rated F5 on the modern-day Fujita scale, but it is now believed to have been part of a family of nine or 10 tornadoes.

Background

Early on April&nbsp;9, the United States Weather Bureau in Amarillo, Texas, forecast late-afternoon temperatures of about over the Texas panhandle. At the time, dense, low-lying stratus and a layer of fog were present, with temperatures ranging from the upper 40s to low 50s °F. However, an approaching warm front—then extended from Sherman, Texas, to Raton, New Mexico—would later combine with a robust trough aloft to enhance conditions for severe weather. In tandem with this, a low-pressure area over northeastern New Mexico, along with an attendant dry line, would gradually eject, leading to stronger low-level wind shear and more pronounced lapse rates. Around 2:00&nbsp;p.m. CST (18:00&nbsp;UTC), helicity was near 135&nbsp;m<sup>2</sup>/s<sup>2</sup>, but would decline afterward. As it did so, however, an unexpected decrease in cloud cover allowed for greater-than-expected diurnal heating, leading to a substantial rise in atmospheric instability and associated buoyancy. By 6:30&nbsp;p.m. CST (00:30&nbsp;UTC), the low-pressure center was situated over southern Colorado, and a jet stream existed above sea level. Surface-based temperatures quickly reached the upper 60s °F. In the mixed layer, the convective available potential energy (CAPE) rose above 1,100&nbsp;j/kg, and the lifted condensation level (LCL) was just above ground level, along with a level of free convection (LFC) of . Mixed-layer convective inhibition by then had decreased, offsetting the loss of helicity, and the presence of the warm front acted in concert with the aforementioned factors to favor supercells capable of generating strong tornadoes. Significant low biases in U.S. tornado counts likely occurred through the early 1990s, when advanced NEXRAD was first installed and the National Weather Service began comprehensively verifying tornado occurrences. 1974 marked the first year where significant tornado (E/F2+) counts became homogenous with contemporary values, attributed to the consistent implementation of Fujita scale assessments. Numerous discrepancies on the details of tornadoes in this outbreak exist between sources. The total count of tornadoes and ratings differs from various agencies accordingly. The list below documents information from the most contemporary official sources alongside assessments from tornado historian Thomas P. Grazulis.

{| class="wikitable sortable" style="width:100%;"

|+ List of confirmed tornadoes in the tornado outbreak of April 9–11, 1947

! scope="col" style="width:2%; text-align:center;"|F#

! scope="col" text-align:center;" class="unsortable"|Location

! scope="col" text-align:center;" class="unsortable"|County / Parish

! scope="col" text-align:center;"|State

! scope="col" align="center"|Date

! scope="col" text-align:center;"|Time (UTC)

! scope="col" text-align:center;"|Path length

! scope="col" text-align:center;"|Width

! scope="col" text-align:center;"|Damage

|-

! scope="row" rowspan="2" style="background-color:#; border-bottom: 1px solid black"| F2

|WSW of White Deer to E of Skellytown

|Carson

|Texas

|

|23:42–?

|

|♯

|

|- class="expand-child"

| colspan="8" style=" border-bottom: 1px solid black;" |This tornado, the first member of the Glazier–Higgins–Woodward family, struck a train, derailing 19 of 61 cars, along with three cabooses. A pair of men were injured aboard. The tornado also damaged several homes, including a farmhouse that was lifted into the air and set back down on its foundation, partly collapsing as a result, resulting in a third injury. Outbuildings and a garage were wrecked as well, and part of a barn was blown away.

|-

! scope="row" rowspan="2" style="background-color:#; border-bottom: 1px solid black"| FU

|NW of Pampa

|Gray, Roberts

|Texas

|

|00:05–?

|

|

|

|- class="expand-child"

| colspan="8" style=" border-bottom: 1px solid black;" |After the White Deer tornado dissipated, a second tornado touched down, remaining over open fields and causing no damage before dissipating.

Aftermath and recovery

A US Weather Bureau report on the F5 tornado that struck Woodward gives the following figures on the damage caused in its "Original Summary" section.

  • Lipscomb County, Texas – 36 homes flattened, 1 damaged
  • Hemphill County, Texas – 83 homes leveled, 116 damaged
  • Texas total – $1,505,000
  • Ellis County, Oklahoma – $1,264,000
  • 52 homes destroyed, 133 damaged
  • 223 other buildings destroyed, 107 damaged
  • Woodward County, Oklahoma – $6,608,750
  • 430 homes destroyed, 650 damaged
  • 925 other buildings destroyed, 975 damaged
  • Woods County, Oklahoma – $950,000
  • 25 homes destroyed, 34 damaged
  • 110 other buildings destroyed, 90 damaged
  • Kansas total – $200,000

Total damage estimates were $173,489,564 (equivalent to $747,850,050 in 2008 dollars).

See also

  • Tornadoes of 1947

Notes

References

Sources

  • (http://docs.lib.noaa.gov/rescue/mwr/075/mwr-075-04-0070.pdf)