FYI tornados actually cannot “suck” doors open. They can only reduce the pressure on the outside, so the force of the air pressure cannot exceed the differential between the air in the shelter and the lower air pressure in the funnel. In reality the shelter is forcing the doer open by its air pressure.
Just the engineer in me ...
Enjoy your day.
Wasn’t that the calculation I showed?
The 100 mb differential pressure between the inside of the vortex and the shelter chamber?
Of course we totally neglected any pressure equalization that would occur because the door is likely poorly sealed.
But it does give a bit of insight into the forces acting.
Or what we call in Indiana “farmer math”