Lacombe resident Mandy Debresser said she was walking by Cranna Lake when she witnessed youths near the area where a fire was set on the trails Tuesday afternoon.
It covered approximately 80 by 60 feet just west of the lake near a culvert around 2:00 P.M.
Eric Nicholas, a fireman who responded to the call says the youths set fire to the area and some damage is visible.
Crews were on the scene right away but it had already been put out by other good samaritans.
There is no harm to the public, however, Lacombe fire does say that area around Cranna Lake is problematic so any reporting of suspicious activity is always recommended.