The waters of the recent floods in Vermont and Massachusetts reached the haymows of hundreds of barns. Excessive heating set in almost immediately after the flood waters receded, endangering the farm buildings. Observations were made at 13 different farms in the valleys of the Winooski, Lamoille and Mississquoi Rivers. These observations are summarized in the following statements: 1. From half a foot to seventeen feet of the piles were under water. 2. In every pile of wet hay observed some ``heating'' had taken place, frequently to the point of being considered dangerous. 3. Heat was generated in the bottom layers of the piles and, escaping up through the hay, led to the production of draughts of hot gases or ``flues'' rising to the surface. 4. The large quantity of moisture carried with the hot gases from the lower layers was condensed on the upper, cooler hay, or in the air above. Many hay piles had been soaked throughout by the falling condensed moisture. 5. While the hot hay was being removed from the barns only one farmer had observed any charred materials. 6. The maximum temperature found (besides one case of fire) was 74 degrees C., though temperatures above 70 degrees were recorded in other places. 7. The most marked evidence of excessive heating was observed (by the farmers) on the second and third days after the recession of the flood waters. 8. One authentic case of ``spontaneous'' combustion of hay caused by the flood was reported. The outstanding features were: a. The lower two feet of the pile consisted of old hay from the preceding season (1926). b. Covering this lower 2-foot section of old hay was a 6-inch layer of first cutting alfalfa. c. Two feet beneath the top surface of the 42-foot pile was another 6-inch layer of alfalfa (second cutting). d. This hay pile which fired ``spontaneously'' was the only one containing even a small quantity of alfalfa. The urgent need for extensive research upon the problem of the ``spontaneous'' heating of farm products was emphasized by the lack of scientific knowledge with which to meet the situation.