The flight may have plunged near Yonkers, but it crashed at Stony Point. It was a flight that left from JFK to Buffalo. Northwest Orient #6231. It seems that the facts were not checked too well in the disaster book, since they claim that it's Yonkers, when it's really a good distance away in Rockland County.
On the same date, December 1st, 1974, another plane crashed in snow on approach to Dulles Airport in Virginia, crashing into Mount Weather, which is FEMA's operations center, a hollowed-out mountain near Washington, DC.
Here's some information on Northwest disasters from Wikipedia:
Northwest Airlines - Wikipedia, the free encyclopedia