Extensive burns to both feet

A 49-year-old male patient presents to the emergency room after escaping from a fire at the local food store. He comes in with extensive burns to both feet and covering approximately 25% of the remainder of his body. The patient is stabilized and flown to the nearest burn center. The burns on his feet are described as including the subcutaneous tissue (see image). There is no muscle, tendon, or bone exposed. What is the correct classification of the severity of this burn?