How to Get Ice Off a Car Window Safely After an Ice Storm

An ice storm leaves a car sealed in a clear, hard shell that a normal frost scraper barely marks. A short Vimeo clip, titled "CarIce" and described by its uploader as "dealing with my car after an ice storm", showed the moment a thick sheet of glaze finally let go of a car window. It was satisfying to watch, and it is also a good excuse to look at the methods that clear glass quickly without cracking it.

Why ice storms glaze cars so thickly

Ordinary frost forms when water vapour freezes onto cold glass overnight, leaving a thin, feathery layer. An ice storm is a different animal. The US National Weather Service defines freezing rain as rain that falls onto a surface whose temperature is below freezing. The drops are liquid in the air and freeze on contact with trees, roads and cars, building up a smooth glaze that bonds tightly to glass and paint.

Because the coating grows drop by drop, it can become several millimetres thick on a car left outside for a night of freezing rain. It also locks wiper blades, door seals and mirror housings in place, which is why the first attempt to open a door after an ice storm so often fails.

How to get ice off a car window, step by step

The safest routine combines gentle heat from inside with patience outside:

1. Start the engine and set the heater to defrost. Point the airflow at the windscreen and turn on the rear-window heater. Warm air from inside loosens the bond between glass and ice.
2. Free the wipers last. Leave them off until the blades have thawed; running frozen wipers can tear the rubber and strain the motor.
3. Use a de-icing spray. A mix of about two parts rubbing alcohol to one part water in a spray bottle melts glaze far faster than water alone, because alcohol lowers the freezing point.
4. Scrape with plastic. Once the ice softens, a plastic scraper lifts it in sheets. Metal scrapers scratch glass and paint.
5. Clear every window, mirror and light. A peephole in the windscreen leaves you blind to the sides and rear.

What not to do with an iced windscreen

Hot water is the classic mistake. Pouring it onto frozen glass creates thermal shock, and a sudden temperature difference across the windscreen can crack it, especially where there is already a small chip. Open flames are just as bad an idea.

Striking the ice with a hammer, wrench or shovel can shatter the window along with the glaze. A dramatic impact makes a fun clip, but on a real morning the aim is clear glass with the car intact, and a few extra minutes of defrosting costs far less than a new windscreen.

Preventing ice on car windows overnight

When freezing rain is in the forecast, a little preparation saves the morning battle:

• Cover the windscreen with a purpose-made cover, an old sheet or a tarp, held down by the closed doors or the wiper arms.
• Lift the wipers off the glass, or slip cardboard under the blades, so they do not freeze in place.
• Park in a garage, carport or under shelter where you can; even a building's lee side catches less glaze.
• Keep a plastic scraper, de-icer spray and gloves in the car through winter.

Plan an extra ten to fifteen minutes on ice-storm mornings. Driving off with partly cleared windows is one of the most common winter hazards, and the roads after freezing rain are usually just as slick as the car.

Related reading

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• A Snow-Covered Car and the Window That Changes the Joke
• The Hunter X6 Photo Gallery: A Large Expedition Vehicle with a Domestic Interior
• Track N Go: A Pickup Truck Track-System Demonstration
• The Canadian Ice Truck: Construction, Driving and Melting
• A Nissan GT-R on the Snow at Kåbdalis
• A Subaru WRX pulls a stuck police car out of the snow
• Slovenia frozen solid after an ice storm

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