By 1860 the Humber Valley was extensively deforested. This decreased the stability of the river banks and increased damages done by periodic flooding. In 1878 a disastrous flood destroyed the remaining water-powered mills. As the Toronto area grew, the lands around the Humber became important farming areas; in addition, some areas of the river's flood plain were developed as residential. This led to serious runoff problems in the 1940s, which the Humber Valley Conservation Authority was established to address. But in 1954, Hurricane Hazel raised the river to devastating flood levels, destroying buildings and bridges; on Raymore Drive, 60 homes were destroyed and 35 people were killed.