A wildfire doesn't have to be near a stable to cause problems for the horses there. Even after a fire is out, there can be lingering problems that affect your horse's health. If your horse has been exposed to any part of a wildfire, even just smoke and ash from afar, please get the horse checked out. The horse might look fine on the outside, but on the inside, it could be a different story.
Smoke and ash inhalation is one of the biggest worries, not just because of the damage it can do, but also because it can occur at a distance from the actual fire. A little, light layer of smoke and no ash may be a bit irritating, but even that may make the horse extra-sensitive for a few weeks. Constant smoke exposure, for example, can result in inflammatory lung disease and bronchopneumonia. What's worse, the symptoms might not show up for a while. It's possible for a horse to look fine right after breathing in brushfire smoke for a while, only for the horse to suddenly fall ill a few days later.
Hoof Damage From Hotspots
When a fire is out, it is still possible for there to be hotspots left, areas that have the potential to reignite. Even if they don't reignite, though, they can burn a horse's hooves if the horse steps on them. If you had to lead your horse through an area that was recently burned, such as when you were trying to evacuate, have the horse's hooves checked for solar damage or damage to the "sole" of the hoof.
Ash is not just an inhaling risk. It can get into the horse's eyes and ears, as well as its nostrils, and it can cause irritation and watery eyes. Horses may need extra water, and they need a thorough checkup to ensure no ash is left in their manes or coat, where the ash could cause further irritation or fly into the horse's eyes later on. While ash looks nice and soft, it's not, and your horse could suffer if the ash is not cleaned off the horse as quickly as possible.
After a brushfire, seek out an equine hospital and have your horse monitored for signs of injury from the fire. Remember that the horse may seem fine at first, so contact your vet and find out what symptoms to look out for over the next several days.