AP Photo/The Billings Gazette, Larry Mayer

Lights from a fire truck streak across a burning hillside in a time exposure as the Dahl fire burns, south of Roundup,overnight Wednesday.

ROUNDUP — Wildfires that have torched more than 200 square miles and burned dozens of homes in southeast Montana spread farther Wednesday, triggering another round of evacuations after a blaze south of Roundup jumped a perimeter line built by firefighters.

The growing, wind-driven Dahl fire, which has burned more than 60 homes by one estimate, forced an unknown number of residents to leave their ho...