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Preparing for snow and ice video

Road Maintenance Field Operations Manager Tony Ledbetter talks about preparing for snow and ice at the King County Road Services Maintenance Headquarters in Renton.

Check your snow route

Will your route be clear this winter?

Primary routes for plowing and sanding in a countywide snow and ice event

2018-19 King County snow routes.
2018-19 unincorporated King County snow routes

Why are there fewer snow routes?

King County crews respond to weather events that affect the bridges and roads of unincorporated areas – the network that keeps communities connected. In past years, the county was able to plow and sand critical snow routes. But the county is no longer funded to plow and sand as much as it used to.

Unfortunately, nearly three decades of annexations, declines in gas tax revenues, and the effects of voter initiatives have led to the chronic underfunding of the local bridge and road system. Fewer resources means fewer staff to perform work during inclement weather as well as year round, resulting in significantly reduced service levels for maintaining roads and bridges in unincorporated areas including plowing and sanding services. Key transportation routes for public safety will be plowed, however, in the past we were able to open secondary routes. The county used to plow and treat 30 percent of county-managed roads, but this year there are only resources to plow 15 percent of the county's 1,500 miles of roads.

Read the Strategic Plan for Road Services (SPRS) update and the Line of Business Plan.

King County Roads and Bridges Task Force
King County Bridges and Roads Task Force

Frequently-asked questions about snow and ice response

The county's response to snow and ice will be different than it was during the last major snow and ice storm in 2010. There are only enough resources to plow 15 percent of county roads, compared to past years when plowing and sanding could keep 30 percent of key routes open. Top priorities for snow removal are principal arterials and emergency routes.
Funding for King County Road Services is spent to replace, operate and maintain roads, bridges and drainage structures. That funding has decreased significantly since 2009 due to declining property and gas taxes. This winter, Road Services has enough year-round staff members to plow 15 percent of the road network during a countywide storm.
Most of the funds the county receives can only be spent for the purpose for which they are collected (for example, your sewer bill pays for sewer work). General county revenues that can be used for any purpose have also declined, so other county services have also been cut back.
The county employs year-round licensed and trained crews that are experienced at operating snow and ice equipment. These crews also provide support for maintaining and preserving roads and bridges throughout the year.

Plowing public roads is dangerous work. Crews need to be proficient in avoiding a variety of hazards, including extreme weather conditions, out-of-control vehicles on slippery roads, abandoned vehicles, children playing near or in the road and steep terrain. With fewer resources, there are only half as many crew members available to provide snow response as the last time there was a major winter storm.
There are two problems with hiring crews on a seasonal basis. First, Northwest winters are unpredictable. Some years the county receives very little snow, while in other years the region must contend with multiple countywide snow and ice events. Even in bad years, the need for snow response is typically short-term, lasting only a few days per event.

Second, there are a very limited number of individuals in the region who are licensed and trained to drive snowplows on county roads under dangerous conditions. The employees who do this work are intimately familiar with county road conditions, hazards, and snow routes, and are experienced in driving graders or 10-yard trucks with plows, sanders, and ice treatment equipment attached. The unpredictable nature of winter storms, the scarcity of licensed and trained workers, and the limited nature of this work combine to make hiring a seasonal workforce challenging.
With the unpredictable Pacific Northwest winter weather, there is little to no market here for private snowplow contractors. There may be individuals or businesses with small trucks with plow blades that are contracted to plow private parking lots or driveways in the winter, but their equipment is too small and fragile to plow long distances on public roads in dangerous conditions. The most effective way for the county to provide a reliable snow and ice response is by having licensed and trained maintenance employees on the job year-round.
The county cannot authorize private citizens to plow public roads. Plowing is dangerous and difficult work. Private individuals without licensing and training who plow a public road risk significant personal liability if someone is hurt or killed, or if property is damaged. Under Washington law, county governments are also responsible for accidents, injuries or damage where the county has authorized work on the road.
County emergency managers are in close contact with both police and fire/rescue agencies during winter weather events. Calls from first responders take precedence over non-emergency calls for assistance. The county's priority snow routes connect police and fire stations, hospitals and emergency centers. Plows will be dispatched to help emergency vehicles gain access into neighborhoods for emergency response.
Each snow and ice storm is unique. The primary snow routes shown on the county's map are the ones that county crews will work to keep open throughout the event by plowing and sanding. However, fallen trees, extraordinary public safety needs, downed power lines or other unforeseen circumstances could result in delays in clearing all roads even in the primary snow route network.

Communities should not expect that roads other than primary snow routes will be plowed and sanded in a countywide snow and ice event. The county works with first responders to clear routes when there are extraordinary public safety issues, but otherwise the county is not likely to have the resources to get to additional roads. Travelers are advised to plan ahead before venturing out during a storm.
A countywide snow and ice event affects most or all roads in King County. Response crews are needed in most or all communities in the county and cannot mobilize to leave one area to assist another. In localized snow and ice events, where snow and ice affects just one or a few parts of the county, response crews may be able to mobilize resources to sand and plow more than just primary routes. However, additional roads are unlikely to be plowed in a countywide storm event.
The Washington State Department of Transportation (WSDOT) manages state highways and freeways. Check WSDOT's snow and ice page for news and information. For snow removal in cities and towns in King County, visit the city or town's website (here's a list of links) and look for snow and ice information or plow routes and maps.

Anti-icing is the application of liquid chemicals to the road surface before the snow begins to fall. Anti-icing is used to help prevent ice from forming. Anti-icing chemicals can be applied to the road prior to a winter storm to help prevent a bond from forming and reduce the amount of time required to restore the roads to a clear, dry state.

De-icing is the process of applying liquid chemicals to the surface of the road after snow and ice has already compacted to it. The application of de-icing chemicals can have the effect of making roadway surfaces slick once they are applied. For this reason, King County crews utilize anti-icing (pretreatment) methods rather than de-icing chemicals.

Pre-wetting involves treating a salt and sand mixture with liquids before they are applied to the roadway. Pre-wetting these materials allows them to better stick to the icy road surface and helps to jump start the ice melting process.


Sodium Chloride (salt) is applied directly to the roadway surfaces once a snow and ice event begins. Salt is sometimes mixed with sand before it is applied to the road. Dry salt is most effective after the snow has accumulated about an inch and the temperature is 20 degrees Fahrenheit or higher. If the temperature is below 20 degrees, salt may not melt enough snow and ice to form a barrier between the pavement and the snow and could even produce more ice as melted snow refreezes. At these temperatures, a mixture of pre-wetted salt and sand are put down to break up ice and increase traction.

Calcium chloride is the chemical used to anti-ice and remove snow and ice from unincorporated King County roadways. Calcium Chloride is able to melt ice at lower temperatures than salt is.

King County may anti-ice when a snow or an ice storm is predicted, when roads are dry and when pavement temperatures are above 20 degrees Fahrenheit. The anticipated temperature and type of precipitation at the start of a storm will also help determine if anti-icing should be used.

Black ice, also known as “glare ice” or “clear ice,” is a thin coating of glazed ice on road. Black ice is not actually black. Instead, it is transparent, allowing you to see the asphalt road surface through it. Black ice often occurs along with wet roads, making it hard to see and especially hazardous for driving or walking.

Ice can form sooner on the decks of bridges and overpasses before it does on the roadway because air can circulate both above and below the surface of the elevated roadway, causing the pavement temperature to drop more rapidly. Ice can also form in shaded areas. Motorists should always use caution and expect slippery conditions when driving during winter weather.