Snowsquall warning

A snowsquall warning is a Canadian weather alert issued by Environment and Climate Change Canada when dangerous snow squalls are expected or occurring.

A snowsquall warning is a Canadian weather alert issued by Environment and Climate Change Canada when dangerous snow squalls are expected or occurring. It warns of intense, localized snowfall, blowing snow, rapidly reduced visibility, and hazardous travel conditions. This alert is part of the winter weather alert family used across the Map of Canada, with particular relevance in snowbelt regions such as the Great Lakes communities and parts of British Columbia, including Vancouver.

Definition

A snowsquall warning is issued when a snow squall is expected to produce dangerous conditions such as heavy snow, blowing snow, and very poor visibility. In Canada, the warning is part of the official severe weather terminology used by Environment and Climate Change Canada.

Types of snow squalls

Canadian guidance recognizes open-water snow squalls, which form downwind of large bodies of water, and frontal snow squalls, which form with the passage of a cold front. Both types can produce sudden visibility loss and hazardous travel, but the meteorological setup differs.

Criteria and impacts

Reported criteria include intense snowfall, reduced visibility below 400 metres, and strong winds; some guidance also notes localized accumulations of 15 centimetres or more in 12 hours or less. Impacts can include whiteout conditions, near-zero visibility, and road closures or travel disruption. A related but more severe alert is the Blizzard Warning, which covers broader and longer-lasting conditions.

Public safety

Public guidance for winter weather alerts emphasizes staying calm, following an emergency plan, and avoiding unnecessary travel when a warning is issued. Local hazard pages advise that snow squalls can make roads dangerous very quickly.