PUBLIC LANDS -- Outdoor recreationists have stumbled into illegal backwoods marijuana growing sites on several occasions already this year.

That's prompted a warning from Forest Service officials: 

Marijuana operations pose significant threats to forest visitors, so it is very important for all national forest users to be aware of their surroundings and any suspicious activities that may be occurring.

Read on for what to look out for and what to do should you encounter a growing site on your next hiking, camping, fishing or hunting trip.

Tips from the Okanogan-Wenatchee National Forest:

If you encounter a drug operation, back out immediately! Leave the way you came in, and make as little noise as possible.  Never engage the growers as these are extremely dangerous people. If you can identify a landmark or record a GPS coordinate, that’s very helpful.

The growers may be present and may or may not know that you have found their operation. Get to a safe place and report the encounter to any uniformed member of the Forest Service or to your local law enforcement agency.  Report as much detail about the location and incident as you can recall.

Forest visitors are urged to pay attention to their surroundings and also watch for possible signs of marijuana growing activity including:

• The smell of marijuana, especially on hot days, is like a skunk.
• Hoses or drip lines located in unusual or unexpected places.
• A well-used trail where there shouldn’t be one.
• Voices coming from an unusual place.
• People standing along roads without vehicles present, or in areas where loitering appears unusual.
• Grow sites are usually found in isolated locations, in rough steep terrain (typically between 500 to 5,500 feet elevation.)
• Camps containing cooking and sleeping areas with food, fertilizer, weapons, garbage, rat poison, and/or dead animals.
• Small propane bottles (so that the grower avoids detection of wood smoke.)
• Individuals armed with rifles out of hunting season.