One or more portions of an inflatable thermal blanket that is sized sufficiently to fully cover a patient are gathered and maintained in a non-inflated condition by a closure such that a thermally-controlled inflating medium admitted into the blanket is prevented from being admitted into the gathered portion(s), thereby leaving a primary part of the patient covered and exposing a part of the patient for medical attention. Thereafter the closure can be released to permit the inflating medium to be admitted into the gathered portion such that the gathered portion self-erects and assumes an inflated condition. The released thermal blanket covers the entire patient and bathes the patient in the inflating medium. The closure can be provided as an elongated tape strip with a central perforation that can be separated.