How atmospheric rivers could cause storm waves in BC

Atmospheric rivers could raise sea levels along the west coast of North America by as much as 200 percent of past levels, a new study has found.

The researchpublished in the journal Communications Earth & Environment focused on the coastal areas of California, Oregon, and Washington.

But lead researcher Christina Shields says the discovery could also have significant implications for British Columbia.

“The main impact on coastal British Columbia will be that (atmospheric rivers) in the future, which are wetter and carry more precipitation, will also have to deal with a temporary increase in ocean height similar to a storm surge,” Shields said.

British Columbia was hit this month by an atmospheric river that killed four people — including two motorists on Vancouver Island, a teacher in a landslide in Coquitlam and a man who was walking near a burst river.

To conduct their research, Shields and her team at the National Center for Atmospheric Research in Boulder, Colorado, used high-precision simulations that more accurately reflect processes in the ocean.

Compared to past studies, she and her colleagues at Texas A&M University and Pennsylvania State University have a more realistic picture of how the ocean behaves when an atmospheric river arrives, she said.

This simulation confirms previous research showing that the river in the atmosphere will be wetter than the sky. But it also showed how often the wind-driven “Pineapple Express” precipitation, which pushes more water toward the coast, can make flooding worse.

According to the researcher, their findings offer “key information” for city managers as they plan to plan for future floods and atmospheric river events in the coming decades.

In an email, Shields said the study modeled future climate projections based on a world where people continue to burn fossil fuels at similar levels.

“Hopefully this scenario doesn’t play out and we can limit emissions so that the consequences are much smaller,” Shields said. “It’s just a possible future.”