The answer to 'why is my tick swarms' is that you likely have a serious tick infestation on your property. Tick swarms are a sign of a large tick population, which can be caused by factors like overgrown vegetation, high humidity, and an abundance of host animals like deer or rodents. Ticks can spread dangerous diseases like Lyme disease, so a tick swarm is a major problem that requires prompt attention.
Ticks thrive in moist, wooded areas, so the first step is to clear any overgrown brush, tall grass, or leaf litter around your home. You can also treat your yard with an insecticide to kill ticks, but this is a temporary solution and the infestation may return. For a long-term solution, you may need to work with a professional pest control company to identify and address the root causes of the tick population.