Highway 5, northbound at Zopkios Rest Area, near the Coquihalla Summit looking north on Jan. 12, 2021. (DriveBC)

Drivers taking one of southern B.C.'s highway passes over the next 24 hours should prepare for a mix of rain and snow, Environment Canada is warning.

The federal forecaster issued special weather statements for stretches of the Coquihalla and Crowsnest highways, saying rain and snow are in the forecast.

"A wintery mix is expected over the highway passes of southern B.C. today through Wednesday," Environment Canada's notice said.

Here's what drivers should watch for:

  • Up to 10 centimetres of snow Tuesday morning followed by 30 millimetres of rain at the Coquihalla Summit along Highway 5. Another 15 centimetres of snow is expected on Wednesday.
  • A similar trend of snow turning to rain then back to flakes at Allison Pass on Highway 3 and Helmer Lake on Highway 5. Less accumulation is expected than at the Coquihalla Summit, however.
  • Up to 25 centimetres of snow on the Okanagan Connector.
  • Up to 25 centimetres of snow at Rogers Pass on Tuesday, followed by another five to 10 centimetres on Wednesday.

"A strong warm front will bring a lot of moisture and increasing snow level to southern B.C. today and tonight," Environment Canada's notice says. 

"The trailing cold front will move across the region from the northwest to southeast on Wednesday, lowering the snow level and producing more snow over the highway passes."

Environment Canada also says the snow level can change dramatically across different locations, with the timing of snowfall expected to vary. Drivers are advised to follow the forecast regularly.

In Metro Vancouver and the Fraser Valley, rainfall warnings predict up to 70 millimetres could fall in some regions by Wednesday evening.