Two warming shelters will be open tonight to keep the homeless out of the cold. The Salvation Army has announced they will be open again tonight from 5:30pm to 7:30pm at the Grass Valley location on Alta Street. They were also open Saturday and Sunday nights. Sierra Roots opened up their cold weather shelter for the homeless last night, and will be open again this evening at the Nevada City Veterans Building. Their hours are 5pm to 7:30am.