Mayor James Baker says the emergency status will remain in effect until midnight Sunday.
Baker says the city has smaller streets and denser neighborhoods that take more time to plow and remove snow.
The mayor is asking drivers to avoid nonessential travel so streets are clear for snow removal.
The mayor's spokesman, John Rago, says the emergency declaration allows the city to tow vehicles from secondary streets as well as from snow emergency routes. It also means the city can bring in more private snow-removal equipment without using normal bidding procedures.