MIXTURE OF COLD AND WARM AIR CAUSES FLOOD

Warm tropical air, saturated with moisture and meeting a drift of cold polar air over the Ohio Valley, is the cause of the floods in that region, Charles F. Brooks '11, Director of the Blue Hill Observatory, told a CRIMSON correspondent last evening.

There has been a high pressure area off the Florida coast for over six weeks, he explained, and this has been causing a steady stream of warm air to flow westward over the Atlantic and then turn north, following the western slopes of the Appalachian Mountains. Over the Ohio Valley, this tropical air meets with a current of cold air from the west which deflects it against the mountains and then forces it to rise.

As the warm, saturated air rises, it cools at an average of 3 1/2 degrees per 1000 feet. At 5000 feet, the height to which Professor Brooks estimates the air is forced, this cooling process would cause it to lose half its moisture.

Two other factors contribute toward excessive rainfall. One is that the polar winds have been recurring in blasts, rather than blowing in a steady stream. This allows the warm air to form in a thicker layer between blasts, concentrating precipitation.

The other factor which has made this flood a record breaker is the effect of an earlier flood in the lower Ohio Valley. This is acting as a water blockade, and is multiplying the destructive forces upstream. The rainfall in some parts of the Vailey has been as much as 20 inches since January 1. The significance of this figure can be better realized when compared with the record rainfall registered on Blue Hill for December, 9.01 inches.