The Tornadoes in Ontario Project (TOP)

The Tornadoes in Ontario Project (TOP) was undertaken to improve the Meteorological Service of Canada tornado database for Ontario. In the past, there have been problems with consistency and discrimination between tornadoes and other types of damaging wind events.

The project is focused on three main areas:

1) improving the quality of data coming into the database each year,

2) updating the database to the current year, and

3) re-evaluating past events in the database and adding missing events.

To address (1), there has been better follow-up on severe weather reports from the public and a greater emphasis on damage surveys. Also, an improved probabilistic methodology for classifying tornadoes has been developed based on the current understanding of damaging wind phenomena. A decision tree was created to help classify tornadoes into 'possible', 'probable', and 'confirmed' categories in a consistent manner. This methodology is now applied to incoming data as well as the work listed in (2) and (3).

To date, tornado events from 1993 to 2003 have been completed and results from this period will be presented at the meeting.