Colorado will spend $21 million to set up an aerial fleet to battle wildfires, after two of the worst fire seasons in state history.

Gov. John Hickenlooper signed a bill May 12 that establishes the Colorado Firefighter Air Corps, and provides $21 million to purchase four helicopters and four planes. Fire suppression costs in 2013 cost the state $48 million, reports CBS Denver.

The aerial fleet will typically respond to an average fire season in which 155 square miles of Colorado are expected to burn.