Tornadoes kill an average of 179 people per year in Bangladesh, the most in the world.Reasons for this include the region's high population density, poor construction quality, and lack of tornado safety knowledge.Other areas of the world that have frequent tornadoes include South Africa, the La Plata Basin area, portions of Europe, Australia and New Zealand, and far eastern Asia.

Tornadoes are most common in spring and least common in winter, but tornadoes can occur any time of year that favorable conditions occur.Spring and fall experience peaks of activity as those are the seasons when stronger winds, wind shear, and atmospheric instability are present.Tornadoes are focused in the right front quadrant of landfalling tropical cyclones, which tend to occur in the late summer and autumn. Tornadoes can also be spawned as a result of eyewall mesovortices, which persist until landfall.
source : https://en.wikipedia.org/wiki/Tornado
The United States has the most tornadoes of any country, nearly four times more than estimated in all of Europe then why does most death related to tornadoes occur in Bangladesh
Reasons for this include Bangladesh high population density, poor construction quality, and lack of tornado safety knowledge.