CHEYENNE, Wyo. (AP) — Investigators have determined that lightning ignited a wildfire that has burned about 3 square miles of timber in a southeast Wyoming national forest.

The fire burning in the Keystone area of Medicine Bow National Forest began July 3.

After growing quickly last week, officials say the fire has been relatively inactive this week thanks for favorable weather conditions, which have allowed firefighters to contain about 15 percent of the fire.

However, they note plenty of heavy fuels in the area that could contribute to fire growth. Firefighters are constructing containment lines and conducting burnouts where they can.

Several small communities in the area have been evacuated and nearby camping areas closed.

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