every 4 years
About twice a year.
once a year
several times a year
About twice a year.
about 1 year tops
TWICE!!
Once
It is very very rare that they will occur maybe 12 tornadoes a year
On average, 1
2.28 per year, roughly.
Most likely once a year.
February 30 does not occur in any year because February only has a maximum of 29 days in a leap year.