CLIMATOLOGY MENU
Tornado tracks

Digital Atmosphere is equipped with a database of United States tornadoes that occurred between 1950 and 2002. These may be plotted on any weather chart for reference purposes. It is important to note that due to limitations in available data, the database carries only the start and end location of a tornado track, and not the intermediate points. This means that tracks will tend to be more accurate for short, slow-moving tornadoes, and much less accurate for long-tracked, fast-moving tornadoes. This is a limitation in the way that tornado climatology is compiled by the National Weather Service, and neither Digital Atmosphere nor its authors have any control over this.

Year. Choose a range of years to display only data during these periods. To display data for only one year, set both blanks to the same value. Choose "all" if you want all years in the database to be displayed.

Month. Choose a range of months to display only data during these periods. To display data for only one month, set both blanks to the same value. Choose "all" if you want all months in the database to be displayed.

Day. Choose a range of days to display only data during these periods. To display data for only one day, set both blanks to the same value. Choose "all" if you want all days in the database to be displayed.

Plot date labels at each track. Digital Atmosphere will plot a MM/DD/YY label to the lower right of the beginning of each tornado track to show which date the track occurred.

Color code. If checked, Digital Atmosphere will code a track black if there were no reported injuries or fatalities, green if there were fatalities but no recorded deaths, and red if deaths occurred.

The source of data is the Storm Prediction Center historical tornado archive, located at http://www.spc.noaa.gov/archive/tornadoes/ . To save disk space, the data has been converted into a series of binary records stored in digatmos.tor that have this structure: Year (signed 32-bit integer); month (unsigned 8-bit integer); day (unsigned 8-bit integer); hour (unsigned 8-bit integer); minute (unsigned 8-bit integer); fujita rating, of which very little data is available (unsigned 8-bit integer); fatalities (signed 32-bit integer); injuries (signed 32-bit integer); latitude of beginning (4-byte float); longitude of beginning (4-byte float); latitude of end (4-byte float); and longitude of end (4-byte float). Weather Graphics does not object to users providing their own updated tornado statistics to replace this one.