The <i>Yakushido Sekibutsu</i> (rock-cliff sculptures of Yakushido) are located at Izumizawa, Odaka, in the Fukushima Prefecture, facing the Pacific Ocean. They are now in a wooden shelter. At present, all sculptures have lost their noses, ears, and other protruding parts, and salts have deposited on their surfaces. From December 1985 to April 1986, temperatures and humidities of the environment were measured. The results showed that the temperature in a sculpture rock (about 2cm deep) was 0°C when the temperature in the shelter was below -2°C during the period between late January and middle February. Frost shattering occurred in the period and actually some damage was observed. Since the main cause of the degradation of the sculptures is frost shattering, the shelter was improved to keep the ambient temperature of the sculptures above 0°C even in the coldest period. In the following winter (1986-1987) no frost shattering was observed. -- AATA