When catastrophic flooding hit Washington and British Columbia in early November, the cause was a weather system that is becoming more common: atmospheric rivers. These phenomenon are what they sound like: rivers of atmospheric water vapor several hundred miles wide that can carry 15 times more water than the Mississippi river.
When these atmospheric rivers hit land, they can dump inches of rain or feet of snow in just a few days, swelling rivers and saturating low lying areas. While hurricanes and tropical storms may be more familiar causes of coastal flooding, atmospheric rivers are a growing threat to homes up and down the West Coast.
Climate change is causing the flow of these atmospheric rivers to increase dramatically. The one responsible for the dramatic flooding in the Pacific Northwest in early November caused $50m of damage in Watcom county along, washing away roads and bridges and effectively cutting parts of British Columbia off from the rest of Canada.
With warmer oceans and more intense atmospheric rivers, homeowners on the West Coast are reconsidering their risk of flooding. Even as climate change makes more volatile weather inevitable, better data can help these homeowners assess their risk and insure against catastrophic flooding losses.
