A river floods, it damages a few tiles and enriches a few tiles. A volcano erupts, it damages or destroys a few tiles, maybe kills some pop, and enriches a few tiles. A tornado comes through and half your empire is gone. It's not fun; it's not even risk/reward balanced. Tornadoes need to have a much smaller effect or be cut entirely--or else reserved for Disaster Level 4 or Apocalypse mode.
You're still ignoring hurricanes, blizzards, forest fires, immortal leaders, wars, trade routes, and everything else that lasts way longer or travels much further than it realistically could. I'm not sure why you're singling our tornadoes.