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Winter Operations and Snow Removal at SEA Airport

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Airport Snow and Ice Responsibility

Sea-Tac 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.

Note: Each airline is responsible for de-icing its aircraft.

Anti-ice Fluid

The airport uses biodegradable potassium acetate as a liquid runway anti-icer. A solid runway deicer, sodium acetate, also is used at lower temperatures. On-site tanks store 62,000 gallons of anti-icing fluid (stored near north Cargo areas). During the last few years, Sea-Tac 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 anti-icing fluid used 2008-2009 season: over 120,000 gallons

Equipment on Hand

Sea-Tac Airport has more than 45 pieces of equipment on hand for snow and ice maintenance including:

  • Nine plow and broom combination units -  state-of-the-art trucks with a 24-foot plow that’s as long as a semi
  • Two friction testers to measure stopping distance for the runways
  • Three sander/plows
  • Seven high-speed plows
  • Four de-icing trucks for roadways [three 75’ wide booms, one 45’ boom]
  • Additional sander, plow and chemical trucks dedicated for landside maintenance
  • Pickup trucks with sanders and plows
  • Seven high-speed plows
  • Five snow blowers
  • 10 high-speed brooms
  • Walk-behind snow blowers
  • Lots of snow shovels and brooms and team members ready to work

Additional Supplies On-hand

300 tons of roadside sand, 350 tons of runway sand, 70 tons of dry chemical (used with sand)

Treatment Procedures

Anti-icing occurs prior to snowfall when temperatures reach 33-34 degrees. Anti-icing fluid works to stop ice from bonding to the concrete. The runways have embedded temperature monitors that allow staff to apply anti-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 30-45 minutes to plow one runway.

Workforce: A normal season budgets 4,000 hours for snow removal.

Largest Recent Snowfall
2008-2009 Snowfall: Overall 23.3” fell during the winter (Sea-Tac’s average snowfall is 12”)

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 below 1000 feet, a Snow Watch may be declared by the airport duty manager. Snow Watch is intended to initiate a heightened state of readiness to address a forecast event. Staffing levels may need to be marginally increased, to cover potential events, at this level. The Snow Watch will be disseminated to Aviation Management for internal section notifications.

Modified Snow Alert: Approximately eight hours prior to the forecasted start of a snow or ice event, a Modified Snow Alert will be declared by the airport operations manager or designee. The Modified Snow Alert is intended to initiate section response to address a forecast event of a smaller scale:

  • Three inches of snow or less in a 24-hour period.
  • Freezing rain/drizzle (less than ¼”).
  • As otherwise determined by Airport Operations, which may be upgraded to Snow Alert if necessary. Removal crews will respond in appropriate numbers to address the forecast event.

Management center for a Modified Snow Alert event is located in Airport Operations Center (AOC). The Modified Snow Alert will be disseminated to Aviation management for internal notifications and to the air carriers serving SEA.

Snow Alert: As soon as it becomes known/apparent that the airport will experience an event of a larger scale:

  • Accumulation of greater than three inches of snow in a 24-hour period.
  • Freezing rain warning (1/4” or more).
  • As otherwise determined by Airport Operations. Snow Alert will be declared by an airport operations senior manager or designee. Included in this notification will be a time to report to the Snow Control Center for the initial responding personnel.

The Snow Alert notification is disseminated to Aviation management for internal notifications and to the air carriers serving SEA.

Snow Control Center

The Snow Control Center is a central management facility for all airport snow and ice control activities. Snow Control Center assists in facilitating increased communications and decision processes associated with a larger snow and ice event.

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