The Montana Army National Guard has closed its three firing ranges in Montana until an investigation into the fire that began at Fort Harrison on Monday is completed.

The 550-acre blaze began when machine gun rounds were fired t at the Fort Harrison weapons training range.

National Guard Public Affairs Specialist Dan Bushnell said investigators will review standard operating procedures and safety precautions "to ensure this doesn't happen again."

The blaze began with three small spot fires on the range at about 2:30 Monday. Firefighters from the Montana National Guard 1049th Engineers and VA firefighters, along with initial attack engines from the National Guard Training Site Headquarters all responded immediately. Although initial efforts nearly extinguished the flames, Bushnell said, the fires rapidly grew together as they were driven by up to 80 mph wind gusts.

"Wind is the denominator here," he said.

The fire quickly spread to the other side of the hill and threatened 30 homes, mainly in the Blue Cloud Estates, before it was knocked out by the combined efforts of federal, state, county and city agencies.

Gov. Brian Schweitzer and members of the media flew over the site of the fire Tuesday to assess the damge.

Firefighters will continue to monitor and "mop up" the charred areas for the next few days, said Bushnell.

Look for the full story in Wednesday's IR.