Washington state and the province of British Columbia are in a state of emergency after days of high winds, rain and flooding. The situation began when an “atmospheric river” (a plume of moisture) spread over the Pacific Northwest, triggering heavy rainfall that overflowed already swollen rivers. This has led to blocked roads, mudslides, fallen bridges and thousands of animals drowning in agricultural areas.
This extensive damage was photographed from space by Earth observation satellites, including the European Space Agency’s (ESA) Copernicus Sentinel mission and the International Space Station (ISS). These images captured the extent of the flooding in the Nooksack and Fraser River valleys this week, both of which overflowed onto their shores this week, resulting in washed-up roads and forcing the evacuation of thousands.
The Sentinel mission is a constellation of two identical Earth observation satellites designed by the EU to provide a wealth of data and images at the heart of the European Union’s Copernicus environmental program. Each satellite carries a wide array of high-resolution multispectral imagers that can photograph Earth’s land and vegetation in 13 different spectral bands.
The image above (top left) was taken by Sentinel-2 in optical strip and shows the flooded areas between the towns of Linden and Ferndale (shown in brown) and all heavy sediment flowing into Lumni and Bellingham Bay (bottom left of image). Sentinel-2 images were unable to penetrate the clouds, but Sentinel-1 took additional photos in the radar strip (top right) on November 4 and 16 (before and after the heavy rains).
These images were combined to create the composite above and indicate the flooded areas in blue, with the darker areas corresponding to the heaviest flooding. In addition to the hundreds of evacuees, more than 158,000 people were affected statewide by the power outages and resulting disruptions to other services. The torrential rains also resulted in mudslides that forced the closure of Interstate 5, which has since been reopened.
In similar news, the former commander of the ISS Colonel Chris Hadfield shared a NASA image via Twitter that shows the extent of the Fraser River flooding in the interior of British Columbia. As he noted in the tweet, the flooding upstream of the river resulted in the dumping of an enormous amount of topsoil into the Salish Sea between the mainland and Vancouver Island, although cases of flow can be observed along the coast of Vancouver Island and Washington State. .
For example, sediment can be seen pouring into Saanich Inlet, the large bay in the lower left of the image that sits between the Saanich Peninsula and the southern tip of Vancouver Island. Further north, there is also flow around the Gulf Islands and between the city of Nanaimo and Gabriola Island (center left). The image also manages to capture flooding imaged by Sentinel satellites, particularly in Bellingham Bay (lower right center) and further south in Puget Sound (lower right).
These images illustrate the extent of this recent extreme weather crisis, described as the worst case of flooding in over a century. They also show how essential Earth observation satellites are in recognizing and treating symptoms of climate change. As average temperatures, sea levels, flooding and extreme weather conditions increase due to higher levels of CO2 in the atmosphere, satellite images help to understand and respond to resulting disasters.
They also help us appreciate the extent of the problem and see it in a way that reminds us that the Earth is a single system and that what happens in one part of the world has direct consequences for all other parts.
Further reading: ESA, CTV News Vancouver