Complex sentence: The fires have been particularly severe due to the ongoing 2011 Southern US drought covering the state, and exacerbating the problem is rapid desertification, the unusual convergence of strong winds, unseasonably warm temperatures, and low humidity.
Split into simpler sentences: The fires have been particularly severe due to the ongoing 2011 Southern US drought covering the state. Exacerbating the problem is rapid desertification, the unusual convergence of strong winds, unseasonably warm temperatures, and low humidity.