Left arm raised at shoulder height, elbow bent and forearm vertical, with palm of hand flat.
Left arm extended straight out from shoulder and pointing in the direction of the turn
Arm raised, elbow bent, with thumb pointing backward in hitch-hiking motion, move arm forward to backward over your shoulder.
Left arm raised at shoulder height, elbow bent and forearm vertical, wrist bent, move arm from left to right over head, pointing to right side of trail.
Left arm extended out and down from the side of the body with a downward flapping motion of hand to signal warning or caution.
Arm raised from the shoulder and extended straight up over the head with palm of hand flat.
*In some jurisdictions,the stop signal may be indicated using the right arm, since the left hand is used for braking. Snowmobilers should watch out for, and be prepared to stop for either signal."
Ground to Air Rescue Signals