I'm north of you here in the state....
My pole barn is built to take a beating and stand...we built it that way purposely knowing the ferocity of storms here.
I give my horses the choice to stay in their barn or outside in the pasture/paddock area.
My neighbor and I open all gates between our lands, allowing the horses acres to wander over...
The horses come and go to her shelter, my barn or the trees as they know where is best for them to be.
Give the horses the opportunity to make their decision...
Batten down and put away all that you can...make the environment as safe as you humanly can...
Make sure now
your fences are strong and do take notice of your trees and clean out the dead wood, the questionable...
Losing 4 trees last year sounds like you had some weakened and diseased trees now culled...gone.
Fences strong and secure...open the barn so shelter is available if they want but they also can use the structure as they need to for protection may not mean in it but maybe better as a wind break and rain softener of intensity... Give the horses their choice...
do better than being locked in in a structure that just doesn't sound made strong to truly protect them.
The list and information shared by Idrivetrotters is sound and valid.
The only thing I can say is by the time they tell you to go, if you have horses it is to late as far as I'm concerned...
It takes longer to travel with a horse trailer...people are idiots on the road and gas shortages are a serious issue..
Be informed of the weather storm and tracking projected and act accordingly.
If you are staying put, then do everything in your power to do it safely and provide safe haven for your animals.
Plan a way to provide clean drinking water for as many days as you can...storm water is often contaminated.
If evacuating...do not wait.
At first mention of it happening, BE GONE!!
Make sure you take coggins and vaccination records as most places still want to see them... Take all your pets, their records required by law...don't forget food and medications for all of the animals.
In this state, micro-chipping is done to many animals because of our storms and damages often occurring.
It is something to consider as every rescue, every animal service vehicle in the state, every animal control officer, every vet....they all have readers and scan animals found to reunite lost humans to their pets.
It works...it truly works...look into it and consider it.
Speak to your vet now, at this quiet time of the year about options, storm evacuation or stay-put suggestions best suited to your particular animals and their needs.
Talk to your particular county about what they offer residents...if they have lists to be on for storm reasons, give them the information they need to help you in time of crisis.