The City of Glen Cove ordered mandatory evacuations of the waterfront areas of East Island, West Island and Shore Rd. by 11 a.m. Monday.
A "strongly recommended" evacuation of the Red Spring Colony area is also in effect, according to the city's website.
Residents are advised to stay with family or friends in nearby areas at higher elevation, or to go to Locust Valley High School at 99 Horse Hollow Rd. in Locust Valley. The school is a designated emergency shelter.
For more information on the city's State of Emergency, which went into effect at 6 a.m. Saturday, visit the city's website.
Residents are asked to remove all cars from city streets to allow for passage of emergency vehicles and debris removal. All parking restrictions are suspended and the city's parking garages are available for safe parking.
"You should be aware that this storm and its effects are predicted to be much worse than last year’s Hurricane Irene," the city said on its website.
Nearly 400 Glen Cove residents lost power Sunday evening, according to LIPA, who had expected to have power restored to those homes by 1 a.m. Monday.