What's the Difference Between a Snowfall Warning and a Blizzard W

4 min read · Thames Valley Snow, London, Ontario

Environment Canada uses specific criteria to decide which type of winter warning to issue, and knowing the difference between a snowfall warning and a blizzard warning helps you understand exactly what kind of conditions to expect.

A snowfall warning is issued when a significant amount of snow, typically 15 centimetres or more within 12 hours, or 25 centimetres or more within 24 hours, is expected. It is primarily about accumulation. Roads get worse, travel slows down, and snow removal becomes a real priority, but visibility and wind are not necessarily part of the equation.

A blizzard warning is a different and more serious classification. It requires sustained winds or frequent gusts of 40 kilometres per hour or more, along with visibility reduced to 400 metres or less due to snow, blowing snow, or a combination of both, lasting for at least four hours. Blizzards do not always require heavy new snowfall. Strong winds can pick up snow that already fell days earlier and create blizzard conditions with barely any fresh accumulation.

The practical difference matters most for travel decisions. A snowfall warning means slower, more careful driving. A blizzard warning often means travel should be avoided entirely, since near-zero visibility combined with high winds creates genuinely dangerous conditions on the road.

Other Winter Alerts You May See

Environment Canada uses several other winter alerts too. A special weather statement is an early heads-up that something unusual may develop. A freezing rain warning means ice is expected to coat roads, sidewalks and power lines. A snow squall warning covers short, intense bursts of snow in narrow bands. An extreme cold warning is about dangerous wind chill rather than snow. Knowing which alert is in effect tells you whether to plan for deep snow, ice, poor visibility or cold.

How to Prepare for Each Warning

For a snowfall warning, fill the gas tank, move vehicles off the street if parking rules apply, and plan extra travel time. For a blizzard warning, plan to stay home if you can, keep phones charged and have flashlights and blankets ready in case the power goes out. In both cases, put away anything on the driveway that could get buried, like bins, hoses or decorations.

What It Means for Your Snow Removal

Heavy snowfall usually means more snow to move in one visit. Blizzards bring drifting, so a driveway that was cleared can fill in again as the wind keeps blowing. With a seasonal plan, service starts automatically once 5 cm of snow falls, so you do not need to call during the storm. Every visit is recorded with timestamped photos. A seasonal plan is $650 and per-visit service is $70.

Wind and Drifting Snow

Drifts build up against fences, garage doors and the edges of driveways, often well after the snow has stopped. If your property sits in an open area, expect drifting after any windy storm. Marking driveway edges before the season helps crews find the edges when snow is deep and blown around.

Frequently Asked Questions

Can a blizzard happen without new snow?

Yes. Strong winds can lift snow that is already on the ground and cut visibility enough to meet blizzard criteria, even with little fresh snowfall.

Will my driveway be cleared during a blizzard?

Service starts once 5 cm has fallen, but in strong wind it often makes sense to clear once the worst drifting eases so the work holds.

Want a set price for your property? Request a free quote or call or text (548) 888-8702. Quotes come back within 2 business days. You can also read about residential snow removal and our prices.

What's included… and what's extra

A Thames Valley Snow seasonal residential plan starts from $650 for a standard driveway. It covers clearing the driveway every time snowfall reaches the trigger depth in your agreement, plus the windrow the city plow leaves at the end of the driveway. Larger driveways are priced on our snow removal prices page.

Popular add-ons, priced per season: walkway and steps $150–175, salting $175, priority service $125, pet-safe salt $120, driveway extension $95 and city sidewalk clearing $90. Add only what your property needs; everything is listed on the quote so there are no surprises. Get your fixed price or call or text (548) 888-8702.