Tsunami!
HUGE tsunami bearing down on a city (which one is that?)!
City (NYC??) getting washed big time.
Tornado!
LA getting hit by something much more associated with Texas or Oklahoma.
Volcano!
Lava floods the streets of LA in
Volcano.
Eruption column seen from the town in
Dante's Peak.
Nuclear war!
'Shroom cloud over a city.
Tactical nuke going off over RAF Finningley near Sheffield, England in the movie
Threads, which I find especially haunting. I read somewhere that when making the film, the simulated explosion was realistic enough that the locals thought the real thing occured - and got the film crew in trouble with the authorities.
Nuclear winter. If you look closely enough, you can see not one, but at least three skeletons.
Asteroid/meteorite impact!
The Chrysler Building gets knocked down in
Armageddon.
What would happen if a Tunguska*-type event occured over Los Angeles.
*In 1908, a comet or an asteroid apparently exploded over the Siberian region of Tunguska with a force equal to that of a 12 megaton nuclear airburst. The explosion likely occured due to the buildup of so much kinetic energy during entry into the atmosphere that the the asteroid or comet couldn't hold itself together anymore and...BOOM.