LUBBOCK, TEXAS HAILSTORM: MAY 7, 1985
by Tim Marshall (June 1985)
We have completed a study of the meteorological conditions involved in the May 7, 1985 hailstorm which moved across Lubbock County, Texas traversing the southwest corner of the city of Lubbock. In particular, documentation of hailstone sizes accompanying the severe thunderstorm is presented.
GENERAL WEATHER SUMMARY
A line of severe thunderstorms developed along and ahead of a dry line during the evening of May 7, 1985. Refer to the appended Figure 1 showing the evening weather situation. The dry line extended from west of Clovis, New Mexico to near Lubbock, Texas to east of Midland, Texas. Warm, moist air originated from over the Gulf of Mexico and was advected northwestward toward Lubbock by southeast surface winds.
Skies over west Texas remained clear throughout the day. Heating of the earth’s surface by the sun further destabilized the lower atmosphere by evening. A weak upper air disturbance moved out of New Mexico and into west Texas during the day. These large scale weather features created an atmosphere favorable for heavy thunderstorm development in west Texas.
At least three severe thunderstorms moved through Lubbock County on the evening of May 7, 1985. Each storm initially developed northwest of Lubbock and tracked southeastward through the west portion of town.
An isolated thunderstorm developed northeast of Lubbock around 6 p.m. The storm grew in size and precipitation area during the hour. By 6:50 p.m., weather service radar indicated a very heavy thunderstorm over west Lubbock. Pea-to-marble size hail was reported by storm spotters at 19th Street and Loop 289. The storm tracked southeastward at 15mph and continued to increase in intensity. Eight minutes later, a severe thunderstorm warning was issued by the Lubbock National Weather Service as half dollar-size hail was reported in west Lubbock.
As the storm traveled into southwest Lubbock, golf ball-size hail fell. Reports of damage, such as broken windows and cracked car windshields, were being received at the Weather Service by 7:15pm. The thunderstorm was most severe in terms of intensity and hail size as it traversed south Lubbock, Wilson, and Woodrow communities. The hailstorm began moving into Lynn County, south of Lubbock, by 7:35 p.m.
A second thunderstorm rapidly developed in southeast Lamb County around 8:05 p.m. and tracked southeastward following a path similar to the first storm. Thirteen minutes later, the storm became severe as it approached Shallowater, just northwest of Lubbock. However, the second storm was not as severe as the first storm. Marble-size hail fell through most of the storm track from Shallowater at 8:58 p.m. to Lubbock, Texas by 9:30 p.m.
A third severe thunderstorm entered Lubbock County around 11:10pm producing baseball-size hail northwest of Abernathy. The storm continued southeastward decreasing in strength. As the storm began to dissipate, rain-cooled outflow air caused gusty winds and marble-size hail throughout central and southern portions of the city of Lubbock.
HAIL SIZES AND CHRONOLOGY
Reports of hail size were obtained from the Lubbock National Weather Service. These hail reports came from public phone calls and ham radio communication. Hail reports were listed in chronological order below and were plotted for the Lubbock area in Figure 2. Hail size was reported as pea (1/4 inch), marble (3/4 inch), golf ball (1.75 inches), and baseball (2.75 inches in diameter). Areas in southwest Lubbock which reported golf ball-size hail or larger were shaded on the figure.
HAIL DAMAGE TO ROOFS
The severe thunderstorms which occurred in southwest Lubbock were associated with a dry line. These types of storms have a tendency to be efficient hail producers without yielding much rain. As a result, roofs have a tendency to be relatively dry and brittle when hail begins. From experience and testing at Haag Laboratories, hail golf ball size or larger possesses enough mass and kinetic energy to cause roofing damage. Wood shingle roofs are most susceptible to splitting if impacted by large hail.
The most severe thunderstorm traveled through southwest Lubbock County between 6:30 and 7:30 p.m. The storm moved from northwest to southeast and produced hail up to baseball-size at 114th and University -and in the town of Wilson, south of Lubbock.