How an ‘atmospheric river’ led to the disastrous isolation of the port of Vancouver

29 March 2022

Written by: Raissa Tiene, Climate consultant, Financial services adaptation,

'Atmospheric river’ led to the disastrous isolation of the port of Vancouver

November 17th 2021, British Columbia experienced historical floods

The Canadian state of British Columbia experienced one of its most severe flood episode in November 2021 (1) just after facing record breaking summer temperatures that lead to wildfires never seen before. The cause of the floods were atmospheric rivers, a narrow band of moisture that flows in the atmosphere from tropical regions (2), which brought exceptional amounts of rainfall from 13th to 15th November 2021 to Northeast Pacific regions of the US and Canada, breaking daily and monthly historical rainfall records in multiple locations (Figure 1). The city of Hope, one of the most affected areas by the floods, registered 174 mm in 24 hours, smashing the previous rainfall record of 34.7mm in 2018 (3). The extreme rainfalls triggered landslides and floods that caused serious damage to critical infrastructures. It is possible that these summer wildfires made the soil more hydrophobic which amplified landslide and washout events (4).

Figure 1: Daily rainfall records in multiple locations across British Columbia (Environment Canada)

What are atmospheric rivers?

An atmospheric river is a long, narrow, horizontal ribbon containing large amounts of water vapor, which flows through the atmosphere, in a similar way as a river (5). When these large amounts of moisture move inland over mountains, the water vapor rises, cools and condenses to produce heavy rain or snow. Generally, these systems area few hundred miles wide and thousands of miles long and they are constantly flowing in the atmosphere, bringing moisture towards the poles.  

The US Geological Surveys states that at any given time across the globe 90% of moisture transport is concentrated in 4 to 5 atmospheric rivers. While most of the atmospheric rivers benefit many regions worldwide (Western US, Canada and Europe, Southeastern South American, Southeast Asia and New-Zealand) by bringing moisture, the more intense rivers can lead to torrential rain for several days, triggering widespread flooding. These locally-heavy precipitations include a substantial fraction of all mid latitude extreme precipitation events (6). Atmospheric rivers are therefore common phenomenon, which according to the latest IPCC report are likely to increase in intensity with climate change (7).

Figure 2: Total precipitable water in the atmosphere (Source: Nasa)

What is the impact of climate change on atmospheric rivers?

As per the 2022 IPCC report on impact, adaptation and vulnerability, atmospheric rivers are likely to become larger and more severe under future global warming projections over many mid latitude regions (7). These projections highlight the Clausius-Clapeyron principle, which states that a warmer atmosphere can hold more water vapour. This phenomenon could trigger more severe precipitation and subsequent flooding during the landfall of atmospheric rivers, impacting our communities and infrastructures (8).

How was the port of Vancouver impacted?

The atmospheric river and its corollaries caused significant supply chain disruption at the port of Vancouver, which handles $1 of every $3 of Canada’s trade in goods outside of North America (9). AON estimated that the damage associated to this event could rise above US$ 2 Billion (10). The landslides and washouts induced by the heavy rainfalls over soils caused damages to the port inland rail androad connections which lengthened the turnaround time of Canada’s largest port (11). Truck drivers were forced to take longer routes through the USA to access the port which hampered drayage operations and led to saturation of storage space (12) (13). This compounded with the ongoing truck driver shortage in Canada that led to an even larger supply chain crunch. Ship backlog peaked at 60 vessels and containers traffic decreased by about 80% (11). It follows that until safe connections could be made to and from the port, the $550 million a day of shipping activity had to be put on a halt (14).

Likewise, with anchorage reaching full capacity during the event, the Vancouver Fraser Port Authority (VFPA) has received complaints about marine and air pollution. Overcapacity at anchorage location affects sea bed ecosystems; and auxiliar­y engines to power ships at anchorage locations emit micro-particles and greenhouse gases (15).

Despite slow reinstatement of inland transport connections, the port of Vancouver struggled to clear the backlog (16). As of December 20th 2021, anchorage occupation was at 81% and demand remained high (17). VFPA stopped communication as of this date ­as it considered the situation under management with rail connections reinstated. Asides from truck driver shortage, reasons for slow resumption of activities could be the increase by 20% of volume of activities in 2021 compared to 2020’s (18).

What can be done at a regional level to adapt?

A better integration of Canada’s transport system could be done through a regional climate resilience strategy plan with a focus on stronger institutional coordination. This could be done through investments in the development of a digital twin (a virtual representation) of all modes of transport for predictive maintenance and to anticipate bottlenecks. Such measures will allow for a better connection of not only the port to inland infrastructures but also will facilitate smart mobilization of alternative transport links in the advent of climate-related hazards.

What can the port authorities do to adapt?

Rather than treating climate risks in isolation, integrating them into an overall risk management strategy might prove more efficient. Better appraisal of the interdependency of climate extreme events and their direct and indirect impacts on the port’s activities needs to be done at the port level for better risks management. This will require both structural and organizational shifts in partnership with regional authorities given the centrality of the port in the Canadian economy. Staff should also be trained on the different vulnerabilities of the supply chain whether on the port’s sub-components, intermodal transport links, energy supply, major trading economies and goods. With such measures in place early warning systems could be developed which will feed into a resilience strategy.

Moreover, with better infrastructure management and port expansion, Canada’s largest port could potentially decrease congestion during catastrophic events. The VFPA and the Canadian authority are planning for the Roberts Bank Terminal 2 expansion (19). However, such projects require decades to implement and are met with growing opposition from wildlife conservationists. This stresses the need for infrastructure management and port expansion strategy to be evaluated at a regional level from the onset; this will allow the participation of all relevant stakeholders in the decision-making process to avoid lengthy implementation and faster proposal of pragmatic alternative measures.  

It is also paramount for the VFPA to invest in predictive technologies targeted at improving communication strategies with both carriers and other operating ports to reduce delays. The port of Rotterdam, for example, is developing a digital twin that will help them effectively target bottlenecks and use land adequately (20). With such technology, infrastructure, shipment movements, weather and geographical locations could all be integrated to optimize the port’s operations and communication strategy with its different stakeholders.

What can private actors using the ports do to adapt?

Shipping companies should leverage predictive analytics before unloading at designated ports to reduce delays (21). With improvement of the visibility of their cargo movement, congested ports can be avoided, and shipment delivery time met.

For more information, contact Raissa Tiene, Climate consultant, Financial services adaptation,

View references

(1)   Sheldon Kusselson (2021): November 11-15, 2021 Atmospheric River event over the Pacific Northwest and British Columbia. VISIT: Meteorological Interpretation Blog.

(2)   NOAA

(3)   CBC News (2021): These graphics show just how much record-breaking rain hit southern B.C. recently. CBC News.

(4)   John Clague (2021): B.C. flooding: the science behind the ‘atmospheric river’ that drenched the province ( TheNarwhal.

(5)   MetMatter (2020): Atmospheric Rivers and Flooding |Royal Meteorological Society (

(6)   IPCC(2021): IPCC_AR6_WGI_Chapter_08.pdf

(7)   IPCC (2022): Climate Change 2022: Impacts, Adaptation, and Vulnerability. Contribution of Working Group II to the Sixth Assessment Report of the Intergovernmental Panel on Climate Change

(8)   Steff Gaulter (2020): Atmospheric Rivers and Flooding. Royal Meteorological Society.

(9)   Port of Vancouver (2021): About us | Port of Vancouver (

(10) RachelDalton (2021): Britis hColumbia floods to cause $2bn economic loss: Aon. Insurance Insider.

(11 ) Nate Tabak (2021): Port of Vancouver ship backlog hits 60 - FreightWaves. Freightwave.

(12) Chuck Chiang (2021): Cargo congestion surge swamps Vancouver -Transportation | Business in Vancouver ( Biv.

(13) Michael Angell (2021): Vancouver port cut off from rail until mid-week ( The journal of Commerce online.

(14) Kat Eschner (2021): Backlog at the Port of Vancouver is a signof supply-chain disruption to come | Fortune. Fortune.

(15) Stephanie Wood (2022): Scientists make final bid to stop Port of Vancouver’s terminal expansion ( The Narwhal.

(16) Hapag Lloyd (2021): Regional Updates in North America. Hapag Lloyd.

(17) Port of Vancouver (2021): Port of Vancouver operations update | Port of Vancouver (

(18) Mark Szakonyi (2021): Container Shipping: Vancouver port faces slow recovery amid new rainfall ( The journal of Commerce online.

(19) Port of Vancouver (2021): Roberts Bank Terminal 2 Project

(20) Ryan Boyles (2019): How the Port of Rotterdam is using IBM digital twin technology to transform itself from the biggest to the smartest. -IBM Business Operations Blog. IBM 

(21) CMA CGM (2021): CMA CGM | SMART containers (

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