City of Seattle Snow & Ice Plan Summary

The City of Seattle has been generally effective in its efforts to deal with unpredictable snowfall. Snowstorms above a certain magnitude that hit in the middle of a weekday, while commuters are at work and must return home, will always cause disruption and delays; however, the city’s Snow and Ice Response Plan allows the city to effectively deal with most situations.

THE PURPOSE OF THE SNOW AND ICE RESPONSE PLAN:

The overall purpose of the City’s Snow and Ice Response Plan is to maintain a network of pre-selected, key routes that provide reasonable access to most areas of the city and the regional transportation system during snow and ice conditions, and
to make all city streets accessible as quickly as possible.

SPECIFIC OBJECTIVES OF THE PLAN:

• Standardize a source of weather forecasting to assure the best assessment of real time weather conditions and supplement it with frequent communication with other cities to obtain the most reliable weather predictions possible.
• Appy anti-icing chemicals as needed and as indicated by weather forecasts at selected locations throughout the city.
  
• Sand and/or plow, as necessary, pre-selected snow routes in accordance with established responses to specific conditions to maintain access by motorists, emergency vehicles, school buses, and transit.
  
• Recognize and respond with special measures to the more difficult conditions created when storms threaten morning or evening peak commute hours.
  
• Prioritize SDOT activities to achieve, in concert with other city departments and outside agencies, the most effective responses possible to a wide variety of conditions.
  
• Provide general seasonal information starting at the beginning of each snow season reminding the public of necessary levels of vehicle preparedness and the difficulties associated with driving in snow and ice conditions.
  
• Provide advance public information on the status of a forecast snowstorm to provide the basis for informed driving decisions, including snow routes and the projected severity and timing of the storm.
  
• Provide ongoing public information during and immediately after a storm about SDOT activities and the status of specific available routes to provide predictability to motorists, King County/Meto Transit, Seattle Police Department, Seattle Fire Department, schools, hospitals, and social service agencies.
  
• Provide other critical city departments and outside agencies with as much assistance as practical to allow them to carry out important activites hindered by snow.

KEY ELEMENTS OF THE CITY’S SNOW AND ICE RESPONSE PLAN:

Pre-Season Preparation

Between the conclusion of one snow season and the beginning of the next, all equipment is inspected, repaired, and tested; materials, parts and supply stocks are checked; work schedules are developed; drivers attend training and/or refresher courses; a preseason interagency coordination meeting is held. Street closure barricades are placed on street corners at the top of steep hills that may be closed in the event of snow.

Weather forecasting

SDOT has standardized its responses predicated upon forecast conditions. Imminent snow conditions are determined by weather forecasts and communication with other cities and outside agencies to determine the severity of snowstorms as well as the speed at which they are approaching Seattle. W hen snow is forecast or falling SDOT staff monitor area traffic cameras to determine what the conditions are in different parts of the area.

Snow Routes

The number of lane-miles that SDOT can maintain during a snow and ice episode depends on the equipment available, the rate at which snow is falling, the temperature and the amount of traffic on the streets. A faster snowfall rate or low temperatures mean streets must be sanded or plowed more frequently, reducing the total area that can be serviced.

Routes that receive first priority are the most important streets for traffic and transit: streets providing access to freeways, major expressways, arterial streets with high volumes of traffic, and streets providing access to hospitals and other emergency services. The secondary response routes are the remainder of the city’s arterial streets. Nonarterial streets receive service on a case by case basis only after primary and secondary routes have been serviced. View the Snow and Ice Routes Map

Transportation Department Responses

SDOT’s trucks maintain lanes coming in and out of downtown giving priority to inbound lanes for the morning commute, and to outbound lanes for the afternoon commute.

SDOT clears the Cherry/Columbia I-5 on-ramps, while WSDOT clears the remainder of the ramps and the I-5 express lanes. WSDOT may close express lanes during heavy snowfall to give priority to sanding and plowing regular lanes, and to allow the State Partol to focus on patrolling regular lanes. WDOT may restrict express lanes to transit only.

SDOT uses anti- icing and de-icing products rather than salt to prevent corrosion while enhancing snow control operations. Street Maintenance crews apply liquid anti-icer on selected elevated structures when there is a forecast of roadway frost or freezing temperatures that may cause road icing problems. The product is used primarily on the West Seattle Bridge (high-level bridge), Alaskan Way Viadut, Spokane Viaduct, Columbia Way ramps, and other elevated roadways.

SDOT has 27 trucks that can be fitted with plows and sanders, and also two de-icer trucks. Additional equipment from other Seattle Department of Transportation (SDOT) divisions is available for snow and ice response when necessary.

SDOT expands service in severe conditions to meet urgent needs of social service agencies.

SDOT’s Street Maintenance and Urban Forestry crews clear streets and sidewalks of downed trees and limbs. If power lines are down with a tree, City Light clears the power lines before SDOT crews remove the tree.

Communications

SDOT coordinates with outside agencies including the Washington State Department of Transportation (WSDOT), King County/Metro, the Seattle School District, and area hospitals as needed during snow and ice events. A Seattle Police Department (SPD) Officer may be stationed at the Charles Street Command Center to facilitate co-ordination between SPD and SDOT. SDOT snow and ice responses are coordinated with the City's Disaster Preparedness and Response Plan.