Lighting and thunder early Monday morning on Whidbey Island underscored the fact that fire season has hit Washington.

The Washington State Department of Natural Resources warns that hot, dry weather and recent and impending thunderstorms have begun fire season.

An increase in lightning strikes coupled with dry grass or other fuels can lead to several fires. A lightning and thunderstorm struck Whidbey Island early Monday morning, at approximately 2 a.m., but no fires resulted.

Still, the leading cause of fires is humans. In 2011, the DNR reported 90 percent of fires were caused by people.

The warning is specific to Eastern Washington, where two wildfires were burning. One in the Wenatchee-Okanogan Forest covered 675 acres, while the other was spread over 225 acres in the Wenas Wildlife Area near Ellensburg. A lightning storm Sunday night and early Monday after a weekend of 80-degree weather led the department to issue a warning to Western Washington as well.