Complex sentence: The 2011 Texas wildfires are an ongoing series of wildfires that peaked in April and May 2011 and by September 12 had burned 3,694,985 acres across Texas, United States.
Split into simpler sentences: The 2011 Texas wildfires are an ongoing series of wildfires that became most intense in April, May, and September 2011. By September 12, they had burned 3,694,985 acres across Texas, United States.