Why did General Washington chose to cross the Delaware under harsh conditions

General Washington chose to cross an ice-chocked Delaware River winter's night because his purpose was to make a surprise attack on a Hessian garrison which consists of 1,400 soldiers located in and around Trenton, New Jersey. Washington had hoped that a fast victory in Trenton would boost morale in his army and encourage additional men to join Continentals rank in the coming new year.