SEA Airport is responsible for snow and ice maintenance of runways, taxiways and the ramp areas (in and around the gates and cargo areas). In addition, the airport is responsible for clearing the terminal area, parking garage, Starling Road, Air Cargo Road to the Employee Parking Lot and the Airport Expressway just north of the return-to-terminal loop. During heavy snowfalls, of approximately three inches or more and accumulating, the Port of Seattle hires local contractors for additional snow removal.
Equipment on hand
SEA Airport has more than 50 pieces of equipment on hand for snow and ice maintenance including:
- 17 plow and broom combination units. 9 tractor trailer units with 24-foot plows. 8 fixed-chassis units with 20-foot plows.
- 2 friction testers to measure stopping distance for the runways
- 4 high-speed brooms
- 3 sander plows
- 4 high-speed plows
- 4 de-icing trucks for runways/taxiways and ramp areas, 3 with 75-foot booms and 1 boomless with a 50-foot spray width
- 5 snow blowers used on the runways
- 4 dump trucks with plows and de-icing and/or sanding capabilities dedicated to landside
- 8 pickup trucks with plows and de-icing and/or sanding capabilities dedicated to landside
- Walk-behind snow blowers and brooms
- Lots of snow shovels and team members ready to work
Ice removal
Note: Each airline is responsible for de-icing its aircraft. Learn more about airplane de-icing
De-icing fluid
The airport uses biodegradable potassium acetate as a liquid runway de-icer. A solid runway de-icer, sodium acetate, also is used at lower temperatures. On-site tanks store 75,000 gallons of de-icing fluid (stored near north cargo areas). During the last few years, SEA used about 36,000 gallons per winter season. De-icing fluid is restocked through a local distributor and ordered when necessary to keep on-site supplies at acceptable levels.
Note: This fluid cannot be used to de-ice aircraft. Airlines use various forms of glycol.
- Average fluid used per season: 36,000 gallons
- Total de-icing fluid used 2021-2022 season: over 120,000 gallons
Additional supplies
- 300 tons of roadside sand
- 350 tons of runway sand
- 70 tons of dry de-icing chemical (can be mixed with sand)
Treatment procedures
De-icing occurs prior to snowfall when temperatures reach 33-34 degrees. De-icing fluid works to stop ice from bonding to the concrete. The runways have embedded temperature monitors that allow staff to apply de-icing fluid when necessary and conserve the supply.
Snow removal on the runways
Snow removal on the runways takes place with several snow plows stretched out at an angle with snow brooms following. It takes approximately 30 minutes to plow one runway.
Workforce: A normal season budgets 4,000 hours for snow removal.
Largest recent snowfall
- February 2019: 20.2 inches
- 2008-2009: Overall 23.3 inches fell during the winter (SEA average snowfall is 6 inches)
Response levels
The following alert levels are used to classify winter weather events at SEA.
Snow Watch
Approximately 24 hours prior to the forecasted start of snow or icing conditions at SEA, or when the snow level in the greater Seattle area is between 600 and 1000 feet, a Snow Watch may be declared by the Airport Duty Manager.
Snow Warning
Approximately 24 hours prior to the forecasted start of snow or icing conditions at SEA, or when the snow level in the greater Seattle area is below 600 feet, a Snow Warning may be declared by the Airport Duty Manager.
Snow Advisory
Approximately 8 hours prior to the forecasted start of a snow or ice event of 2 inches of snow or less in a 24-hour period, freezing rain/drizzle (less than ¼ inch), or as otherwise determined by the Senior Manager, Airport Operations. Snow Advisory will be declared by Airport Operations Manager or designee.
Snow Alert
At any time if forecasted accumulation of snow is greater than 3 inches in a 24-hour period, freezing rain warning (¼ inch or more), or as otherwise determined by the Senior Manager, Airport Operations.
Snow Demobilization
At any time after a snow event where snow removal has taken place, Snow Demobilization will be declared by the contacted Airport Operations Manager or designee. The Snow Control Center will reduce to a modified staffing level and ramp cleanup will continue until areas return to normal operations.
Snow Control Center
The Snow Control Center (SCC) is a central management operation for all airport snow and ice control activities. The SCC assists in facilitating increased communications and decision processes associated with a larger snow and ice event.
