raintorm

‘Atmospheric river’ rainstorm headed for Fraser Valley, up to 70 mm expected

‘Atmospheric river’ rainstorm headed for Fraser Valley, up to 70 mm expected

A heavy rainstorm is expected to hit the Fraser Valley, bringing 50 to 70 millimetres of rain, according to a warning from Environment Canada. Meteorologists call this type of rain pattern an “atmospheric river.” It’s caused by narrow regions in the atmosphere transporting water vapor outside the tropics. Once the vapor hits land, it releases in the form of rain or snow.