On November 3 and 4, 1927, torrential rains fell over much of New England, causing the most severe floods of which we have knowledge over extensive areas in Vermont, New Hampshire, Massachusetts, Connecticut, and Rhode Island.  Vermont experienced an exceedingly heavy rainfall, the area of greatest precipitation centering on the long ridge of the Green Mountains and extending southward over western Massachusetts into Connecticut. A smaller area of equal and possibly much greater rainfall centered on the White Mountains of New Hampshire, with lighter rainfall over the southern and northern portions of the State. A third area of much smaller extent, but with recorded intensities of precipitation practically as great as in Vermont, centered in northern Rhode Island and extended northward to Worcester, Mass. 

    The destructiveness of such a storm depends upon a number of circumstances, important among which are the character of the soil, the topography, the condition of the ground and of the streams and ponds, and the rate of precipitation. At the time of this storm the ground had been thoroughly saturated by heavy rains which fell from the 18th to the 21st of October. The natural lakes and swamps had been filled, and most of the rivers had been raised to medium high stages, so that practically all the surface storage available had been utilized less than two weeks before the storm. 

    As a result, the rivers quickly overflowed their banks, spread over meadows and farm lands in the first bottoms, and filled many of the valleys from hill to hill. The grades of the streams are so steep that excessively high velocities were attained, and the rushing waters washed out bridges, retaining walls, dams, road embankments, buildings, and farm lands. In many sections of the mountainous country near the headwaters the flood peaks arrived suddenly and at night, the inhabitants were taken unawares, and many were unable to reach safety before being drowned in their homes. The report of the Advisory Committee of Engineers on Flood Control, State of Vermont, shows that the total number of lives lost in the State was 84, and of these 55 were in the Winooski River Basin. 

    Robert M. Ross, commissioner of forestry, State of Vermont, and chairman of the Vermont Flood Survey, states that the damage to cities, villages, railroads, and other public utilities was over $14,000,000; to highways and bridges, $7,000,000; and the total damage more than $28,000,000. The other States suffered severely but less than Vermont. 

    Only by careful analyses of data concerning flood magnitude is it possible to study adequately the problem of flood control; and flood control is a very necessary part of complete utilization of the water resources of a region. Many feasible reservoir sites in the devastated area have not yet been developed because the expense is apparently unwarranted by the demand for utilization of the stored water for power. However, a detailed study of these sites as reservoirs for flood prevention combined with power developments may show that the construction of the projects would be warranted, if the cost were equitably divided among those who would be benefited. 

    Although damages to property resulting from failure of engineering structures may be evaluated as a basis for determining the limit of economic cost of such structures, the loss of life cannot be evaluated. Structures whose safety involves human life should be designed much more securely than those whose failure would involve damage to property alone. 

    As a general rule, storms that visit the northeastern section of the United States approach from a westerly direction and are of moderate intensity. Occasionally a storm is blown in from the Atlantic Ocean by an east or northeast wind, and the rainfall in such a storm is likely to be high. At more rare intervals tropical storms are forced inland, entering the New England States from the south and proceeding northward. These storms are usually attended by heavy precipitation. The great storm of November 1927, and perhaps all storms producing abnormally high rainfall in the past have been of this nature. 

    From a study of meteorologic data and storm centers, it appears that several factors combined their influence to cause conditions of rare occurrence, which produced a storm of unusual proportions. These factors were indicated by weather maps issued by the United States Weather Bureau immediately before and during the storm and were discussed in several published reports, especially the paper by J. H. Weber and C. F. Brooks, of Clark University, Worcester, Mass.

    Of greatest effect was the steady approach of a tropical storm from the south, which according to the weather map first appeared almost directly over Cuba as early as October 29. This storm was not of unusual severity and did not show much action until November 1, when it started northward, reaching a point off the coast of South Carolina by the night of November 2. By the morning of November 3 the storm center had reached the lower end of Chesapeake Bay. 

    As predicted by the United States Weather Bureau at Washington, on the evening of November 2, under normal conditions the storm would have continued up the coast with moderately heavy rains and with light showers in central New England, causing little if any disturbance. However, out to the northeast an extensive area of exceedingly high pressure prevented the storm from proceeding in that direction. At the same time a high-pressure area had moved in from the northwest to a position north of New York State. Thus the tropical storm was caught between the two cold areas of high pressure and was forced to pass over them, causing torrential rainfall. 

    The effectiveness of this barrier is indicated by the great range in temperature on its sides. A difference of 19° occurred in about 80 miles between warm Amherst, Mass., and cold Albany, N.Y., on the west, and between warm Brattleboro, Vt., and cold Northfield, Vt., on the north. Converging winds were observed at midnight November 3, of a velocity of 50 miles an hour from the southeast at Providence, R. I., and of 8 miles an hour from the north at Worcester, Mass. During the hour after these observations rain fell at Worcester at the rate of nearly 2 inches an hour. 

    The path of least resistance, as indicated by the pressures shown on Figure 7, was directly over western Massachusetts and Vermont. The great stream of warm moisture-laden air was not only forced over the Berkshire Hills and Green Mountains, whose altitudes range from 1,500 to 3,000 feet, but in addition it was thrust upward over the barrier of cold, heavy air moving down from the north, which was just as effective as the mountains in forcing the warm air upward. 

    The warm moist air was cooled so greatly as it reached the higher altitudes that much of its moisture carrying capacity was lost, and it therefore yielded tremendous quantities of rain. As the air became cooled it moved on, giving place to more moist air from the unfailing supply, and this in turn yielded its quota of moisture. As the meteorologic conditions remained practically unchanged over a period of 24 hours, it is not difficult to account for the excessive rainfall which was reported in the path of the storm. 

    The magnitude of the northward movement of the moist tropical air was indicated by the low-pressure area which extended from the Appalachian Mountains on the west to a point a considerable distance east of the Atlantic coast. This immense body of moisture-bearing air was moving at a high velocity through the funnel-shaped exit over New England. At Boston, Mass., the highest aerologic observation, nearly 2 miles above the surface, indicated a wind blowing from the south at a velocity of 45 miles an hour, while at 6,500 feet the rate was 51 miles an hour. Both at Worcester, Mass., and at Washington, D. C. the highest clouds visible during the storm were moving rapidly from the south. 

    The storm of November, 1927, was general over the northeastern section of the United States, but the greatest effect was concentrated over western New England. Records from Vermont and New Hampshire indicate that the precipitation increased with the altitude. Unfortunately, no rainfall records were obtained from the high areas of the Green Mountains in Vermont and the White Mountains in New Hampshire. Were such records available, they would undoubtedly show a much greater rainfall than any record obtained during the storm. Records were obtained from only two areas receiving more than 9 inches of rain. One was a long, narrow area along the summit of the Green Mountains in central Vermont, and the other was a small area in southwestern Rhode Island. The total area in which there was a precipitation of 9 inches or more was about 500 square miles. 

    Records of precipitation have been collected by the United States Weather Bureau, by X. H. Goodnough, chief engineer of the Department of Public Health of the Commonwealth of Massachusetts, and by many private persons. The rainfall records were well distributed over the territory affected by the storm, with the exception of the areas near the tops of the mountain ranges. 

    The following records have been taken from a paper by Goodnough. They include the records of the numerous rain gages of the United States Weather Bureau in all parts of New England and the adjacent sections of New York, the records of the Department of Public Health in Massachusetts, and the results of observations by many power companies, water departments and companies, and private observers.