To support the development of NCTD’s CAIRP, NCTD identified existing climate hazards and potential impacts to North County transportation infrastructure.
The project team analyzed state, regional, and local agencies' plans that evaluate climate hazards and is developing relevant strategies and actions NCTD can take to mitigate and adapt to the climate hazards it faces.
The preliminary evaluation identified the following climate hazards:
These hazards pose significant challenges to the transportation systems as a whole as well as to specific assets and services. Climate hazards can damage infrastructure and cause unsafe conditions for rail and bus passengers. These impacts can lead to disruptions in services, operations, and could require costly repairs and alterations. The following section discusses climate hazards and how they impact both the transit system and human health.
Climate hazards can impact passenger health and comfort. For example, extreme heat, particularly when coupled with humidity, can affect passenger health and comfort, which may reduce ridership or lead to public health issues.
Climate hazards can slow or delay transit services. For example, during extreme temperature events, agencies may issue precautionary speed restrictions on rail services to prevent damage which can lead to delays.
Climate hazards can damage transportation system components. For example, earthquakes can damage rail structures such as tunnels and bridges, leading to costly and lengthy repairs.
Extreme heat, particularly when coupled with humidity, can affect passenger health and comfort using the transit system. Extreme heat can cause damage to rail tracks. If extreme heat damages tracks, operations can be suspended on the impacted tracks. Passengers can also experience heat related health impacts waiting on station platforms without proper cover or in rail cars without cooling. Extreme heat for passengers at bus stops without shelters during a high heat index (HI) temperature can be even more impactful on human health. If a HI is expected to be above 105°F in San Diego, the National Weather Service (NWS) initiates a heat warning alert. Bus stop shelters or tree canopy can provide shade and reduce the impacts of extreme heat.
Extreme cold can freeze rail tracks, which can cause cracks and separation of tracks that can lead to delays or service suspension. In certain instances, precautionary speed restrictions can prevent damage to rail tracks, however this would result in service delays. Extreme cold can also impact passenger health and comfort, waiting at stations if the stations lack proper heating. Extreme cold can impact passenger health and comfort at bus stops. Bus shelters can reduce the impact of extreme cold and installing heaters can further improve passenger comfort. However, most bus shelters are not equipped with a heating system.
Extreme wind conditions alone can cause be a hazard to passengers waiting at rail stations. Debris and trees downed by extreme winds can damage or obstruct rail tracks causing delays as well as block access to rail stations or cause hazards on the platforms. Extreme wind can also be hazardous to passengers waiting at bus stops. Debris and trees downed by extreme winds can cause service delays and impact safety by blocking roadways, bus stops, or curb access. Extreme wind can also disrupt power to rail stations, bus stops, and traffic signals that cause service disruptions.
Coastal Hazards Erosion impacting the Del Mar Bluffs (image NCTD)
Transit services operating in the areas where rail tracks are located along the coastline or in low-lying areas could be subject to sea level rise, coastal flooding, storm surge, and shoreline erosion. Coastal hazards can flood underground and at-grade rail stations with saline water, which can damage tracks and equipment causing service disruptions. Coastal hazards can also inundate roads and disrupt bus operations. Roadway flooding, downed trees, and debris can close roadways and cause detours, delays, or suspension of service. Coastal bluffs are a part of the North County coastline and are vulnerable to erosion. On August 22, 2018, a section of the Del Mar bluffs collapsed onto the beach in close proximity to the North County Transit District (NCTD) rail line. NCTD temporarily suspended services to inspect the impact to the rail tracks and ensure it was safe to resume rail services. The stabilization of the Del Mar bluffs is an ongoing, multiphase effort to maintain safe, stable, and reliable train tracks through this stretch of the LOSSAN Corridor. For more information, please visit:
SANDAG’s project website.
San Dieguito River Railway Bridge in Del Mar (Image NCTD)
Tsunamis are giant waves caused by earthquakes or volcanic eruptions under the sea and as the waves travel inland, they can cause damage and flooding. Tsunamis can damage rail tracks by sheer force of water or moving debris. Tsunamis can also damage rail stations by partially or completely closing stations due to the force of the water, flooding, or depositing debris. Tsunamis can damage bus stop shelters by the force of the water or depositing debris. Bus services can also be impacted by tsunamis due to flooding or deposit debris, which can damage roads leading to road closures and detours. Damage and flooding from tsunamis to rail tracks, stations, and roadways can cause service interruptions until flooding and debris can be cleared.
Flooding and erosion on Highway 78
The wood trestle San Dieguito River Railway Bridge in Del Mar is a critical part of the LOSSAN Corridor and is vulnerable to the impacts of climate change including sea level rise, flooding, and washout damage.
Extreme precipitation can cause flooding or move debris that can block rail tracks. Flooding can make at-grade tracks slippery and cause delays or inundate them, leading to suspended operations. Heavy precipitation can disrupt access to platforms, flooding station entrances and forcing closures. It can also cause flood and cause leaks on platforms.
Extreme precipitation can also impact passenger health and comfort at bus stops. Bus shelters and tree canopy can reduce the impact of extreme precipitation by providing shelter and further improve passenger comfort. Extreme precipitation and flooding can close roadways that become inundated with debris. Roadway flood inundation can cause detours, delays, or service suspension.
California Wildfires (image Caltrans)
Wildfires can damage rail tracks through heat alone or can cause secondary impacts like debris blown or downed trees over tracks. Wildfires can damage rail stations and equipment causing partial or complete closures. Wildfires can damage bus stop shelters or can cause secondary impacts like debris blown or downed trees blocking access to bus stops. Wildfires can lead to road closures, detours, and service suspensions. Power outages from wildfires or downed power lines from debris can cause service disruptions or suspensions. Secondary impacts from fires can impact human health due to poor air quality.
Roadway Damage (image Caltrans)
Earthquakes can cause damage to rail tracks by offsetting alignment, breaking and pulling apart joints, as well as causing debris blocking tracks. Earthquakes can also cause damage to track structures, such as tunnels and bridges. Depending on the severity of damage to rail stations due to earthquakes, stations can be partially or completely closed. Earthquakes can damage bus stop shelters making them unusable or inaccessible. Damage from earthquakes can cause cracks and surface ruptures to roadways, requiring suspension of services or detours in services.
Drought can cause groundwater depletion, which carries some risk of causing sinkholes. Sinkholes can damage track alignment or roadways, which could cause disruptions in rail and bus services.
Stabilization of the Del Mar bluffs is an ongoing, multiphase effort to maintain safe, stable, and reliable train tracks through this stretch of the LOSSAN Corridor. For more information, please visit
SANDAG’s project website.