Impressive.
Based on some stories I’ve seen about doors being sucked open, you might also consider beefing up the latch.
It has two chain locks on it.... can’t really see them in that picture. It’s 8 x 8 .... 7 foot tall inside. Well stocked :)
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.