Pioneer Day fireworks cause fires in Spanish Fork, Tooele At least two fires in northern Utah were confirmed to have been started by fireworks on Pioneer Day as Utah struggles with an extreme drought impacting almost all of the state. and last updated 2021-07-25 22:47:47-04 SPANISH FORK, Utah â At least two fires in northern Utah were confirmed to have been started by fireworks on Pioneer Day as Utah struggles with an extreme drought impacting almost all of the state. The hay was still smoking Sunday morning at a barn in Spanish Fork, which was the scene of a large structure fire just after midnight.