How atmospheric rivers could cause storm surges in BC

More powerful atmospheric rivers could lead to higher storm surges and flooding in the future, research shows.

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

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

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

“The biggest impact for the British Columbia coast would be that in the future, (atmospheric rivers), which will be wetter and carry more precipitation, will also experience a temporary increase in ocean height, similar to a storm surge,” Shields said.

This month, BC was hit by an atmospheric river that led to the deaths of four people — including two drivers on Vancouver Island, a teacher in a mudslide in Coquitlam and a man walking near a swollen river.

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

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

This modeling reinforces previous research showing that atmospheric rivers will be wetter from the air. But it also showed how the often windy ‘Pineapple Express’ rainstorms, which push more water onto the coast, can lead to worsening flooding.

Their findings provide “important information” for city managers as they plan for future flooding and atmospheric river events in the coming decades, the researcher said.

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

“Hopefully this scenario will not become a reality and we can reduce emissions so that the consequences will be much less,” Shields said. “It’s just a possible future.”