What Is a Freezing Drizzle Advisory?
A Freezing Drizzle Advisory is issued by Environment and Climate Change Canada (ECCC) when freezing drizzle is expected to create icy and potentially hazardous conditions.
Freezing drizzle consists of very small liquid water droplets that freeze when they come into contact with cold surfaces. Even light drizzle can gradually create a thin layer of ice on roads, sidewalks and other exposed surfaces.
When Is a Freezing Drizzle Advisory Issued in Canada?
A Freezing Drizzle Advisory may be issued when a period of freezing drizzle is expected to create hazardous icy conditions.
Meteorologists look at temperatures near the surface and at different levels of the atmosphere, along with cloud moisture and expected precipitation. Freezing drizzle can occur when liquid droplets remain unfrozen in the atmosphere but freeze after reaching surfaces that are at or below freezing.
Because even small amounts of ice can make roads and sidewalks slippery, the impacts of freezing drizzle can be significant despite the precipitation appearing light.
Read More: How Do Meteorologists Predict Freezing Rain?
What to Expect During a Freezing Drizzle Advisory
Expect light precipitation that may not look particularly severe but can gradually create icy surfaces.
Roads, sidewalks, parking lots, driveways and stairs can become slippery. Untreated surfaces, bridges and overpasses may become icy more quickly because they can cool faster than surrounding roads.
Freezing drizzle can also create a thin coating of ice on vehicles, trees and other exposed objects.
How Freezing Drizzle Can Affect Travel
The main concern during freezing drizzle is the formation of slippery surfaces.
Road conditions can become hazardous even when precipitation is very light. Drivers may have less traction when accelerating, braking or turning, while pedestrians can encounter difficult conditions on untreated sidewalks and walkways.
Conditions may also vary along a route, particularly where surface temperatures differ.
What to Do When a Freezing Drizzle Advisory Is Issued
Check current weather and road conditions before travelling. If you need to drive, reduce your speed, allow additional stopping distance and avoid sudden braking or acceleration.
Use extra caution on bridges, overpasses and untreated roads where ice may develop first.
Pedestrians should also watch for icy sidewalks, stairs and parking lots that may not appear slippery at first glance.
Continue checking the advisory for updates, particularly if temperatures are expected to remain near or below freezing.
Related Winter Weather Alerts
Freezing drizzle can occur alongside other types of winter precipitation, so other alerts may also be issued as conditions change.
Freezing Rain Warning
Issued when freezing rain is expected to create significant ice accumulation and hazardous conditions.
Winter Storm Warning
May be issued when a combination of severe winter hazards, such as snow, freezing rain or strong winds, is expected.
Snowfall Warning
Issued when significant snowfall is expected to create hazardous conditions.
Learn More About Freezing Drizzle
Freezing Drizzle — Small liquid water droplets that freeze when they come into contact with surfaces at or below freezing.
Freezing Rain — Liquid precipitation that freezes on contact with cold surfaces, often involving larger droplets and the potential for more substantial ice accumulation.
Black Ice — A thin, difficult-to-see layer of ice that can make roads and walkways extremely slippery.
Understanding the difference between freezing drizzle and freezing rain is useful because both can create icy conditions even though the precipitation may remain liquid until it reaches the surface.
Frequently Asked Questions
A Freezing Drizzle Advisory means freezing drizzle is expected to create icy surfaces and potentially hazardous travel conditions.
A Freezing Drizzle Advisory should be taken seriously because even small amounts of ice can make roads and sidewalks dangerous.
Freezing drizzle occurs when small supercooled liquid water droplets fall and freeze when they contact surfaces at or below freezing.
Yes. Freezing drizzle can create thin and difficult-to-see layers of ice that increase the risk of vehicle collisions and falls.
Freezing drizzle consists of smaller droplets, while freezing rain consists of larger raindrops. Freezing rain may generally produce greater ice accumulation and more significant impacts.
If conditions change and a more significant freezing precipitation event is expected, Environment and Climate Change Canada may issue the appropriate weather warning.
No. Freezing drizzle is a type of precipitation, while black ice is a thin and difficult-to-see layer of ice that can develop on roads and other surfaces.
Sources
- https://www.canada.ca/en/services/environment/weather/severeweather/weather-alerts.html
- https://www.canada.ca/en/environment-climate-change/services/seasonal-weather-hazards/severe-winter.html
- https://www.canada.ca/en/services/environment/weather/severeweather/weather-alerts/weather-impact-guides.html
- https://www.canada.ca/en/services/environment/weather/radar-satellites.html
- https://www.canada.ca/en/services/policing/emergencies/preparedness/get-prepared/hazards-emergencies/winter-storms/how-prepare.html
- https://www.canada.ca/en/environment-climate-change/services/weather-general-tools-resources/weather-webmapping.html
- https://www.canada.ca/en/environment-climate-change/services/weather-general-tools-resources/weathercan.html
