[Tagging] tagging 'closed during fire ban days'

[Warin]

Hi,

The local National Parks look to have introduced a 'safety measure'.

Signs have gone up saying the trails/tracks are closed during fire ban 
days. The fire bans are declared by the Fire Service - usually when it 
is both hot and windy.

So .. how to tag?

opening_hours - free text input?

OR

access tag ?

Thoughts, ideas...

I'm inclined to opening hours .. as that would be applicable to all and 
thus fits the situation so opening_hours=closed during fire ban days.