A high strength low alloy steel, with considerable ductility at room temperature used in Arctic pipelines is characterized with respect to fracture. Both static and dynamic loading modes are examined. The fracture toughness parameters K//I//c, K//I//d, J//I//c and J//I//d are obtained as a function of temperature and crack orientation. A brittle-ductile transition temperature is defined which is a function of the crack orientation and the severity of the crack. The relation between the energy of initiation and propagation of the crack and temperature further substantiate this transition temperature.