The first figure shows the annual number of tornadoes per year in Marylnad since 1950 plotting data from NCEI's Storm Events Database. Beginning in the 1990s, the number of tornadoes has increased dramatically with wider variations from year to year.
The second figure shows the lack of any systematic change in the stronger tornado events - those classified as F1 to F5 in the original Fujita Scale. These represent the tornadoes that cause at least moderate damage and are well documented. No climate trend exists in these stronger events.
The third figure shows the upward trend in the number of the weakest F0 tornadoes. These rarely cause any damage and traditionally were ignored. The upward trend in recent years is the result of better radar systems, better spotter networks, and increased awareness and interest by the public.