Airports And Snow: When Do Flights Shut Down?

Heavy snow and ice can cause major disruptions to airports, with some closing their runways until the weather improves. In January 2025, a winter storm caused almost all flights out of Ronald Reagan Washington National Airport to be canceled, with the airport closing its runways for snow removal. The same storm also caused significant disruption to flights at Dulles International and Baltimore/Washington International Thurgood Marshall Airport. In Europe, snow and ice caused multiple UK airports to close their runways, including Manchester Airport, Liverpool's John Lennon Airport, and Newcastle International Airport. Frankfurt Airport in Germany also saw dozens of flights canceled. While snow can cause airports to shut down, it is not the only factor that determines whether an airport remains operational during winter weather.

Snow removal and runway closure

When snow accumulates on runways, it must be promptly cleared to maintain safe operations. Airports typically have snow plows and other specialized equipment to remove snow and slush from runways and taxiways. In addition to physical removal, de-icing procedures are also necessary to prevent ice buildup on runways and aircraft. De-icing fluid is used to treat surfaces and aircraft before takeoff, and this process must occur within a specific timeframe to be effective. If snow continues to fall, a second de-icing procedure may be required.

Runway closures for snow removal and de-icing are often necessary to ensure the safety of aircraft operations. In some cases, airports may choose to close runways temporarily to facilitate efficient snow removal and de-icing. For example, during a winter storm in January 2025, Ronald Reagan Washington National Airport closed its runways for the night to allow for snow removal and did not reopen until the following morning. Similarly, Manchester Airport in the UK temporarily closed its runways due to heavy snow, reopening after staff cleared the snow.

The decision to close a runway due to snow and ice is influenced by several factors, including the rate of snowfall, the effectiveness of snow removal operations, and the need for de-icing. Airports aim to minimize disruptions by efficiently clearing snow and treating surfaces, but closures may be necessary during heavy or continuous snowfall. Additionally, the presence of ice can further complicate operations, as it poses a significant hazard to aircraft and ground equipment. Freezing rain, freezing drizzle, and freezing fog can all contribute to ice accretion, necessitating more time-consuming de-icing procedures.

Overall, snow removal and runway closure are critical aspects of airport operations during winter weather. Efficient snow removal, de-icing procedures, and temporary runway closures help ensure the safety of aircraft and passengers during snowy conditions. By proactively managing these challenges, airports can minimize delays and disruptions while maintaining safe operations.

De-icing aircraft

Aircraft de-icing is a safety procedure that removes snow, ice, or frost from the wings and fuselage of an aircraft. This process is usually carried out by spraying specific fluids onto the aircraft's surfaces through specialised vehicles similar to cherry pickers. De-icing is done just before the aircraft departs and is a standard procedure at most airports during winter.

De-icing vs Anti-icing

De-icing refers to the removal of snow or ice that has already built up on the aircraft's surface. Anti-icing, on the other hand, involves treating surfaces to prevent the formation of frost, ice, or snow.

De-icing fluids

For de-icing, a fluid called propylene glycol is used. This orange-coloured fluid is heated to around 60–65°C and sprayed over the aircraft under pressure, removing any existing snow, ice, or slush. The amount of water mixed with propylene glycol depends on the conditions, such as temperature, contamination level, and aircraft type. Ethylene glycol-based fluids are also used for de-icing in some parts of the world but are more toxic.

Anti-icing fluids

Anti-icing fluids, also known as Type IV fluids, are generally green in colour and are not heated. They contain thickening agents instead of water, increasing their viscosity so they adhere better to the aircraft's surfaces.

Where and when is de-icing done?

Aircraft de-icing can be performed at any airport with winter operations in place. De-icing is typically done at the aircraft's gate or stand, after pushback, or at designated de-icing pads at larger airports. It is carried out just before departure to ensure sufficient time to melt or blow off any built-up ice before takeoff.

Holdover Time

The term "Holdover Time" refers to the time between the application of de-icing fluids and the aircraft's takeoff. De-icing fluids typically have a holdover time of around 20 minutes, while anti-icing fluids can last anywhere from 10 minutes to over 2 hours, depending on weather conditions. If an aircraft exceeds its holdover time, it must undergo the de-icing process again.

Delayed and cancelled flights

Heavy snowfall can cause significant disruptions to air travel, with multiple airports sometimes forced to close their runways temporarily. This was the case in the UK in January 2025, when several airports, including Manchester Airport, Liverpool's John Lennon Airport, and Newcastle International Airport, closed their runways due to heavy snow and ice.

Snowfall can cause significant logistical challenges for airport management, leading to delayed and cancelled flights. De-icing requirements, combined with runway clearance, can cause significant delays, especially at airports that experience infrequent snowfall. For instance, in Madrid, the airport was closed for two days in January 2021 due to a snowstorm.

In the US, winter storms can cause thousands of flights to be cancelled or delayed. During a winter storm in January 2025, almost 2,000 flights within, to, or from the US were cancelled, and a further 2,400 flights were delayed. Ronald Reagan Washington National Airport had the highest number of inbound and outbound cancellations, with around 250 departing flights and 200 arriving flights cancelled. Baltimore/Washington International Thurgood Marshall Airport had the second-highest number of outbound cancellations, with around 110.

Airlines are required to offer refunds or rebooking options to passengers whose flights are cancelled or significantly delayed. According to airline compensation expert Ivaylo Danailov of SkyRefund, "regulations [...] mandate that airlines automatically provide cash refunds for cancelled or significantly changed flights without requiring passengers to request them." A "significant change" is defined as a delay exceeding three hours for domestic flights or six hours for international flights.

Impact on airport personnel and passengers

Snowfall can have a significant impact on airport personnel and passengers, leading to delays and disruptions in travel plans. While airport operations aim to continue as smoothly as possible, heavy snowfall can cause temporary closures of runways and affect flight schedules.

During snow events, airport personnel work tirelessly to ensure the safety and well-being of passengers and staff. They implement snow removal procedures, including clearing runways and treating airfield surfaces to make them safe for aircraft movement. This involves the use of snow plows and de-icing equipment to maintain the integrity of the runways and prevent accidents.

Passengers may experience flight delays or cancellations due to snow. In some cases, airports may temporarily close runways to facilitate snow removal and de-icing, causing disruptions to travel plans. Passengers may have to deal with rescheduled flights, find alternative routes, or even spend extended periods at the airport until conditions improve.

The impact of snow on airport personnel and passengers can vary depending on the airport's location and experience in handling winter weather. Airports in warmer climates that rarely experience snow may face greater challenges, as they may have fewer resources and equipment to manage snow removal and de-icing efficiently. On the other hand, airports in colder climates may have more established procedures and resources to handle snowfall, minimizing the impact on operations.

To mitigate the impact of snow, airports strive to provide accurate and timely information to passengers. They may offer travel advisories, recommend rebooking options, and provide updates on flight statuses. Additionally, passengers can take proactive measures, such as checking flight statuses, allowing for potential delays, and familiarizing themselves with their rights regarding refunds or rebooking options in the event of cancellations or significant delays.

Snowfall in irregular climates

Snowfall can cause travel disruptions, including flight cancellations and delays, as airports may need to close runways for snow removal and de-icing procedures. While some airports in colder climates have more experience dealing with snow, snowfall in irregular climates can also impact airports and travel.

Additionally, irregular snowfall can affect the snow-to-precipitation ratio in these regions. When temperatures are warmer, more winter precipitation falls as rain instead of snow. This can lead to changes in the amount and timing of snowfall, impacting various aspects of life, such as water supply, recreation, and the spawning of fish.

The Pacific Northwest and parts of the Midwest have seen a decline in total snowfall and the proportion of precipitation falling as snow. On the other hand, some areas near the Great Lakes now receive more snow than in the past. Climate change is a contributing factor to these shifts in snowfall patterns, leading to more winter precipitation falling as rain instead of snow.

It is important to note that even airports in colder climates can be significantly affected by snowfall. For instance, Dallas/Fort Worth International Airport has consistently ranked high in delays and cancellations due to winter weather.

To minimise the impact of snowfall on travel, passengers are advised to stay informed about flight delays and cancellations, choose alternative hubs if possible, and be proactive in rebooking flights when necessary.

Frequently asked questions