Today in Lubbock & Waco F-5 tornado history

[Ed Lizard]

26 dead, about 500 injured.

http://lubbockonline..._page#loopbegin

METEOROLOGY:

The thunderstorm that spawned the Lubbock tornado was unique in that it formed on a retreating dryline. The dryline is a narrow boundary between dry continental air to the west and moist air from the Gulf of Mexico to the east. It is often present across the high plains of the U.S. during the springtime and is especially common in the south plains of West Texas. When there is not a strong storm system bringing winds that will overwhelm the dryline, the dryline will move east (advance) during the day as the air heats up and then will move back to the west (retreat) during the evening. While thunderstorms often form along advancing drylines during the afternoon and can produce large hail and even tornadoes, thunderstorms that form along retreating drylines are much less frequent, and only rarely produce tornadoes. This is due in part to the air becoming more stable (air temperature decreases less rapidly with height) as the air cools near the ground after the sun sets.

The figures below show the atmospheric conditions that existed leading up to and during the Lubbock tornado. These are common maps that meteorologists use to examine the state of the atmosphere. In the 1970s, the only ways to collect information from the atmosphere above the surface was to use weather balloons. For more information on these balloons please

click here.

...

The dryline initially made its way east of Lubbock during the early afternoon, with winds shifting from south to west and dewpoints, which are a measure of the moisture in the air, dropping from lower 60s at 10 am CDT to mid 30s by 1 pm.

Click here to view the hourly observations taken at the Lubbock Airport on May 10, 11, and 12, 1970.

However, as the

4 pm surface map and observations show, the winds quickly switch back around to the south at the airport, preventing the moisture and dryline from advancing far from Lubbock. Although surface observations in West Texas were sparse in 1970, they did manage to pinpoint the area of confluence (air coming together) associated with the dryline to be located between Reese AFB, with a light west wind and the Lubbock airport, with a south wind. Temperatures had also warmed nicely, under sunny skies, into the lower and middle 90s.

Three hours later, at

7 pm, the surface map continued to depict the dryline, and related confluence, between Reese AFB and the Lubbock airport. This extended period of confluence near Lubbock aided in the development of clouds and eventually thunderstorms as the warm and increasingly moist air that was coming together at the surface was forced to rise. Additionally, the 7 pm observation at the airport indicated that cumulonimbus clouds, which are dense, vertically developed clouds that produce thunderstorms, were visible to the south and distant northeast of the airport. The surface map indicates the approximate locations that the isolated thunderstorms had developed.

Finally, the

10 pm surface map reveals that the dryline had continued its retreat more rapidly off to the west, with moisture and southeast winds returning to southeast New Mexico, Reese AFB, and Amarillo. The thunderstorms that were developing at 7 pm were now mature, feeding off of abundant low-level moisture supplied by strong southeast winds.

...The

500 millibar map shows how the atmosphere looks at around 18,000 feet (5400 meters). The map shows a trough of low pressure across the northwest United States (heights decrease from 5880 meters over the Gulf of Mexico to 5460 meters near California and Oregon. In addition, look at the 5820 (labeled 582 on the map) line. You can see two small waves - one over Oklahoma and one moving through West Texas. This second wave trough (waves have ridges and troughs) is labeled with a red dashed line. Sometimes, subtle waves like this can provide just enough lift (thunderstorm development requires moisture, instability and lift) to get thunderstorms going. The stronger area of winds shaded in blue centered near Midland are also an indication of this wave. Winds in the atmosphere are created by pressure differences, which in turn are caused by temperature differences. Areas of higher winds at this altitude are often caused by sharp temperature contrasts. This enhanced temperature contrasts means that there may be a pocket of cold air aloft (cold air aloft provides the energy for instability and lift).

Soundings from Abilene, Midland and Amarillo also in above linked NWS LUB(LBB) write-up.

http://www.lubbocktornado1970.com/

Survivor stories

What were you doing in Lubbock in May 1970?

I was seven years old living with my parents Jose and Pauline Zarazua at my home on 1st street. On May 11 1970 I was staying with my Grandfather who was babysitting, at our home along with my three sisters & brother. My parents were both at work.

What do you remember from the night of May 11, 1970?

While staying with my Grandfather it began to get very dark and when it started to rain heavily my Grandfather called us inside. It began to thunder heavier than I ever heard before. It was like we were in a war zone being bombed. Then the hail started they were like baseballs and when they started hitting the roof my sisters and brother and I began to cry. the wind started to rattle the windows and it seemed like they would break at any time, finally one did. My grandfather Anastacio Ortega was a man of faith and he immediately got us together and we all started praying. Just then the phone rang ,it was my mother. She was at work and was worrying about us. We all talked to her and asked her when she was coming home. Little did I know but it would be the last time we would ever speak to her. The storm was getting worse but my Grandfather remained steadfast in his Faith. He did his best to calm us and continued to pray. As he did we realized that it was our only hope. We all got on our knees and learned the power of prayer from him that night. I believe it was prayer that saved us. Shortly after the storm stopped my Father returned home. He gave my Granfather a ride back to his home.

What was your reaction to the destruction you saw in the days following the storm? Did the storm damage your home, workplace, or school?

The next morning my Mother still was not home. Then family members began to gather at our home. There were trees knocked down and debris everywhere but our concern was our mother. My Father heard that there were Victims of the tornado at Smiley Wilson JH. My Father along with an Aunt & Uncle accompanied him. I can't imagine the horror they saw when they got there. All that was said was that the only way they could identify my mother was by her green dress and wedding ring.

[Ed Lizard]

http://lubbockonline.com/stories/010309/loc_373680407.shtml

Bend in the tower still visible.

[Ian]

waco today too

[Ed Lizard]

waco today too

I'm not sure who wrote the Wiki, has a very 1970s feel to some parts.

According to an old Huaco Native American legend, tornadoes could not touch down in Waco. Most storms in the area travel from west to east and split around the Waco area due to the bluffs around the Brazos River, making tornadoes and extreme weather relatively rare and mild in the city. The 1953 storm, however, traveled against the prevailing winds, and the tornado approached Waco from the south-southwest.

[aslkahuna]

Just like the Indian legend that Burnett's Mound would protect Topeka KS. When I went to Whiteman AFB as my first USAF assignment, I was told that the ridgeline between us and Warrensburg protected the Base from tornadoes. A year and a half later a tornado did a Werhmacht style end run around the ridge and ran right over the Base-fortunately it had weakened to an EF0-1 by then.

Steve