Abstract: A marking device is disclosed. The marking device includes a marker housing. The marker housing includes an attachment portion configured to pivotally attach the marker housing to a pole. The marker housing also includes a translucent portion formed around at least a portion of the housing. The marker housing also includes an environmental seal. The marking device includes an electrical light positioned within the marker housing and oriented toward the translucent portion, and a programmable circuit configured to activate the electrical light in one or more marking flashing patterns. The environmental seal protects the electrical light and programmable circuit from external environmental conditions. Optionally, the device can clip to a marker such as a flag to indicate the existence of a hazardous condition.