Yesterday, the nation watched in horror as a 2-mile-wide tornado struck the city of Moore, a major metropolitan area just outside of Oklahoma City, Okla.
The twister destroyed more than 28-square miles of Moore, and has been preliminarily classified as an EF4 with sustained winds of 200 mph. Judging by the photos and videos coming in, it looks like it will surpass the destruction caused by a May 3, 1999 tornado that hit the same area and is long-considered to be the worst in history. Astoundingly, this was the third-major tornado to hit the city of Moore in the past 15 years.
We dug through some documents, publications and resources within the Scribd library that may help put some of yesterday’s horrific news in perspective, along with some further resources about the nature and science of tornadoes and climate study. We also highly encourage you to follow the American Red Cross on Scribd, as they have a ton of fantastic resources about how we can all strive to be better prepared before, during and in the aftermath of a natural disaster.
The storm that hit Moore, Okla. in 1999 was rated an F5 – the most powerful storm in a category that goes from F0 through F5. Initially developed by Tetsuya Fujita at the University of Chicago in 1971, this scale was the first true method to rate the speed and classify tornadoes. It was retroactively appended to all tornadoes going back to 1950, which leaves a relatively shallow history of tornadic rankings. One of the worst outside the May, 1999 storms, was a tornado that hit Flint on June 8, 1953, killing 116. Only recently was it surpassed by the Joplin, MO. tornado that killed 162 in 2011. Currently, the deadliest comes prior to the implementation and classification available in the Fujita Scale, which struck March 18, 1925, killed 695 people in Illinois, Missouri and Indiana. As a country, tornado awareness and preparedness has come very far, helping save thousands of lives.
In 2007, the Fujita Scale was updated to more accurately match wind speeds to the severity of damage caused by the tornado and also improve damage surveying in the wake of a twister. This document helps understand the major ways a tornado is classified in the new scale.
Scribd Publisher: National Press Foundation
Lightning Does Strikes Twice
The odds that two tornadoes would have struck Moore, Okla. in the past ten years are astronomic. The fact that two, incredibly powerful tornadoes would track roughly the same path are even higher. That is essentially what happened. All three of the tornadoes that hit Moore in the past 15 years were within the same vicinity. The two extremely powerful twisters — in 1999, and the one yesterday, both tracked eerily close together, destroying a majority of Moore in both instances. In 1999, 65 people were killed and 300 mph winds destroyed more than 8,000 structures. Until today, that twister was considered one of the deadliest and most costly, at $1 billion in damages.
The National Press Foundation published this study that looks at the May 3, 1999 tornado from a historical perspective and charts the number of deaths and analyzes what that means for preparedness and the type of facilities we have at our disposal to escape to in the time of a storm. For example, 11 of the deaths from the May 1999 tornado were in mobile homes. The study looks at the increasing trend of Americans living in mobile homes and the impact that could have on future tornadoes, especially in regions ill-equipped for basements, such as Oklahoma. There, homes are mostly built on slabs.
Scribd Publisher: National Press Foundation
Climate & Tornadoes
Read the first chapter from S.C. Pryor’s book Climate Change in the Midwest. The research presented in this volume focuses on identifying and quantifying the major vulnerabilities to climate change in the Midwestern United States and has implications on the strength and types of storms that impacted Okla.
Scribd Publisher: Indiana University Press
Upper Midwest Twisters
Sitting outside of ‘Tornado Alley,’ the Upper Midwest is also known for its share of violent storms and destructive tornadoes. The Wisconsin Tornado Atlas gives historical charts, maps and tables that document historical tornado occurrence in the state starting in 1950.
This research paper also helps understand a hazard model for predicting tornado frequency in the United States using the Monte Carlo Method.