Update: 6 p.m., Saturday Mayor Greg Nickels has announced that a fleet of 27 snow plows are clearing Seattle roads and seven utility repair crews stand ready to respond as a winter storm hits the region.

Two trucks will be dedicated to the West Seattle Bridge and the Alaskan Way Viaduct

The city of Seattle activated its Emergency Operations Center at 2 p.m. on Saturday, coordinating responses by the Department of Transportation, Seattle City Light, Seattle Public Utilities, Human Services, Police, Fire and Parks departments.

Snow and ice removal crews will continue clearing arterial roads through the night. Road conditions may become icy tonight as

temperatures drop.

The Seattle Department of Transportation is urging residents only to drive if necessary.

A primary concern tonight is expected to be high winds, particular in east King County. At this hour, there are no power outages within the city of Seattle, but City Light is prepared to call in as many crews as needed if conditions change.

Three severe weather shelters remain open at least through Monday night: City Hall, Frye Hotel, and Seattle Center Pavilion B. Shelter beds are still available. Last night, 143 people stayed at the three shelters. During the day, Seattle residents can find warm, public space at Parks Department community centers and the Seattle Center. The following community centers will be open on Sunday from noon to 5 p.m.: Garfield Community Center, Rainier Beach Community Center, South Park Community Center, Rainier Community Center and Hiawatha Community Center.

Seattle's recycling and garbage transfer stations will be closed tomorrow. Solid waste customers who were missed for pickup today should bring in their containers until next week.

Seattle Public Utilities reminds residents to prepare water pipes for cold weather. Shut off outside faucets, drain the water and protect them by insulating them with rags or foam covers. Pipes in exposed or unheated areas (attics, basements and garages) should be wrapped with tape and insulating materials, available at local hardware stores.

Drain and remove all outdoor hoses, and shut off and drain in-ground sprinkler systems.

Residents are also urged to protect indoor sink pipes that are against exterior walls, by opening under-sink cabinet doors, allowing heat to circulate. During severe cold, allow the faucet farthest from your front door to slowly drip cold water. Set your thermostat no lower than 55 degrees Fahrenheit, day or night (even if you are away).

If a water pipe breaks, immediately close the main shut-off valve to stop excessive flooding. If you cannot turn off the main shut-off valve, Public Utility customers can call (206) 386-1800 and a crew will turn off the water at the meter for a standard service charge.

Update: 4 p.m., Saturday City Light preparing high winds

Seattle City Light has issues a winter storm warning for Saturday, Dec. 20.

?We are concerned about the possibility of some high winds hitting our service area late this afternoon,? City Light Superintendent Jorge Carrasco said. ?We are holding some crews to be ready for what may hit us later today. Our fleet is chained up and fully equipped in order to respond to possible outages. We are prepared for the storm that will pass through the area later today. Snow is generally not a problem for power delivery, however, severe cold, ice and wind can become a problem for us.?

City Light reminds customers to be safe and what to do if they do experience a power outage::

Do not get within 10? of any downed wire. Wires should always be assumed to be ?live? and dangerous. If someone seeks a downed wire, they should call 684-706-0051;

Do not use a barbecue grill or generator inside the house or in a garage that is attached to the house. Do not use a grill or generator near a home air intake vent or near windows;

Do not use fossil fuel burning auxiliary heating sources;

Have an emergency power outage kit available and well-stocked. Make sure all batteries are fresh. To find out what to put into a kit, go to www.takewinterbystorm.org

Know how to manually override electric garage doors, security doors and gates;

Have a land line phone or fully charged cell phone available - cordless phones won?t work when the power is out;

Unplug electrical appliances if the power goes out so that when the power comes back on, there won?t be a surge that could damage sensitive electronic equipment;

Use battery-powered flashlights - not candles or oil lamps;

Close doors, windows, curtains, and unused fireplace dampers to retain heat if there is an outage.

Update: 4:27 p.m., Friday Ballard Metro Transit routes, 17, 15, 18 and 28 have no service north of Northwest 85th Street.

Route 44 is operating its regular route.

Update: 2:40 p.m., Friday High winds forecast this weekend may lead to power outages in some parts of the city.

"We can't predict which neighborhoods if any may lose power, so we want to encourage all residents of King County to have a plan about how to stay warm and safe during adverse weather," said Dr. David Fleming, director and health officer for Public Health, Seattle and King County. "If possible today, stock up on supplies you may need during the weekend and think about how you will stay warm and safe during a possible outage."

Given the cold temperatures, Public Health advises all residents to take steps to stay safe and warm and especially to avoid carbon monoxide poisoning.

"City crews have been working around the clock making great progress on our main roads, but drivers still need to be extremely cautious getting around town,? said Mayor Greg Nickels in a statement just released. ?We ask drivers to be patient and use their best judgment especially on Seattle?s steep hills.?

Crews operating 20 plow and sanding trucks remain on 12-hour shifts and will continue working through the night. An additional 40 personnel worked through the day to clear sidewalks and stairways near critical pedestrian locations, such as hospitals and food banks. As temperatures are expected to drop significantly later today, roadway surfaces may refreeze. The city will continue to monitor pavement conditions closely and will again put priority on primary arterials, especially the West Seattle Bridge and the Alaskan Way Viaduct, if conditions worsen.

While the strongest winds are expected to hit the Cascades and foothills, the Seattle area could see sustained winds of 20 to 30 mph, according to the National Weather Service.

Public golf courses, Interbay, Jackson Park, West Seattle and Jefferson Park are closed.

If power goes out, the County recommends the following:

Keep the doors closed on your refrigerators and freezers as much as possible. This keeps the cold air inside. A full freezer can stay at freezing temperatures about two days; a half-full freezer about 1 day.

If you think the power will be out for several days, try to find some ice to pack inside your refrigerator. Remember to keep your raw foods separate from your ready-to-eat foods.

Refrigerated foods should be safe as long as the power is out no more than a few hours and the refrigerator/freezer doors have been kept closed. Potentially hazardous foods, such as meat and fish, should be discarded if they warm up above 41