From the Data dot Gov website, this data set: https://explore.data.gov/d/8vq3-ke4t
…has been turned into a stunning image of the United states. Each line represents an individual tornado, while the brightness of the line represents its intensity on the Fujita Scale. The result, rendered by John Nelson of the IDV User Experience, shows some interesting things, especially the timeline bargraph that goes with the map, which show that the majority of US tornado related deaths and injury (prior to the 2011 outbreak which isn’t in this dataset) happened in the 1950’s to the 1970’s. This is a testament to NEXRAD doppler radar, improved forecasting, and better warning systems combined with improved media coverage.
Here’s the data description, the big map of the CONUS follows below.
The National Weather Service (NWS) Storm Prediction Center (SPC) routinely collects reports of severe weather and compiles them with public access from the database called SeverePlot (Hart and Janish 1999) with a Graphic Information System (GIS). The composite SVRGIS information is made available to the public primarily in .zip files of approximately 50MB size. The files located at the access point contain track information regarding known tornados during the period 1950 to 2006. Although available to all, the data provided may be of particular value to weather professionals and students of meteorological sciences. An instructional manual is provided on how to build and develop a basic severe weather report GIS database in ArcGis and is located at the technical documentation site contained in this metadata catalog.
It is also worth noting that the distribution of strong tornadoes -vs- weaker tornadoes (rated by the Fujita scale) is greatly lopsided, with the weakest tornadoes far outnumbering the strong killer F5 tornadoes (such as we saw in 1974 and 2011, both cooler La Niña years) by at least an order of magnitude:
And here’s the entire map, click for a very hi-resolution version:
Mike Smith covers a lot of the history contained in this data set in his book Warnings The True Story of How Science Tamed the Weather.
He talks about the vast improvements we’ve witnessed since the early days of severe weather forecasting and is well worth a read if you want to understand severe weather in the USA and how the detection and warning methods have evolved. He has another book just out (Reviewed by Pielke Sr. that explains the failure of this system in Joplin in 2011.
In Mike Smith’s first book, “Warnings: The True Story of How Science Tamed the Weather,” we learned the only thing separating American society from triple-digit fatalities from tornadoes, weather-related plane crashes, and hurricanes is the storm warning system that was carefully crafted over the last 50 years. That acclaimed book, as one reviewer put it, “made meteorologists the most unlikely heroes of recent literature.” But, what if the warning system failed to provide a clear, timely notice of a major storm? Tragically, that scenario played out in Joplin, Missouri, on May 22, 2011. As a wedding, a high school graduation, and shopping trips were in progress, an invisible monster storm was developing west of the city. When it arrived, many were caught unaware. One hundred sixty-one perished and one thousand were injured. “When the Sirens Were Silent” is the gripping story of the Joplin tornado. It recounts that horrible day with a goal of insuring this does not happen again.
Of course, alarmists like Peter Gleick (who knows little about operational meteorology and is prone to law-breaking) like to tell us severe weather (and days like Joplin) are a consequence of global warming saying at the Huffington Post:
“More extreme and violent climate is a direct consequence of human-caused climate change (whether or not we can determine if these particular tornado outbreaks were caused or worsened by climate change).”
But in this story from Physorg.com
“If you look at the past 60 years of data, the number of tornadoes is increasing significantly, but it’s agreed upon by the tornado community that it’s not a real increase,” said Grady Dixon, assistant professor of meteorology and climatology at Mississippi State University.
“It’s having to do with better (weather tracking) technology, more population, the fact that the population is better educated and more aware. So we’re seeing them more often,” Dixon said.
But he said it would be “a terrible mistake” to relate the up-tick to climate change.
Again, for a full understanding I urge readers to click, read, and to distribute these two WUWT essays: