As more buildings succumbed to the flames, a major contributing factor to the fire's spread was a meteorological phenomenon known as a fire whirl. As overheated air rises, it comes into contact with cooler air and begins to spin creating a tornado-like effect. These fire whirls are likely what drove flaming debris so high and so far. Such debris was blown across the main branch of the Chicago River to a railroad car carrying kerosene. The fire had jumped the river a second time and was now raging across the city's north side. Also likely a factor in the fire's rapid spread was the amount of flammable waste that had accumulated in the river from years of improper disposal methods used by local industries.