Working detached garage fire with exposure to residence. Two car garage fully involved upon arrival. Side two of single story frame involved. Due to heavy snow on roof of garage, collapse occured just prior to crews entry. This also assisted in extinguishment of the house fire. Flames were somewhat supressed under the roof. A 2 1/2" and 1 3/4" line were pulled initially then a third line, 1 3/4" with piercing nozzle was used to penetrate under the roof section. Extensive overhaul by truck crews. RIT team present. No injuries reported. $35,000 loss to building and cars in garage. Response to incident included 4 engine companies, a truck, DC, and medic.