A few weeks ago, I had a day off and decided to take my dog Ghost and an old pal to Killarney, Ont., for a hike. Killarney is a small town about an hour from Sudbury with a provincial park, beautiful trails, and some of the best fish and chips you’ll find for miles.

The plan was a leisurely drive down Highway 637, a winding stretch of scenic tarmac with plenty of sections in a less-than-stellar state of repair. We’d park at the entrance to a popular hiking trail, spend a few hours in the wilderness, and then head into town nearby for a post-hike meal of fresh fish and chips.

Intent on not driving on my day off, I asked my friend to take the wheel of my 2019 Volkswagen Alltrack for the drive. I sat shotgun and Ghost waited excitedly for his hike in the back of the wagon.

A few moments away from our destination, the car’s glass sunroof panel suddenly exploded with a loud bang, sending glass shards everywhere. Expletives and emergency braking came next. Not only did the explosion ruin my planned excursion, but the terrifying incident also put me, my friend, and my dog in danger.

A quick Google search for “sunroof explosion” reveals that many brands and makes and models are implicated when owners report their sunroof’s glass panel spontaneously exploding.

Volkswagen is one of those brands, but there are many others. Stories and circumstances vary widely when it comes to sunroof explosions and failures, but no matter the cause, it’s always a scary occurrence.

What Caused the Explosion?

I was a bartender for many years before reviewing cars for a living and spent many evenings handling glass for hours on end. I can confirm that glass can just explode, sometimes seemingly randomly. On multiple occasions, I’ve witnessed glassware shatter when touched lightly or explode when it makes contact with the cold metal nozzle of a beer tap. Extreme temperature changes might cause glass to shatter sometimes, but it can also be much more random than that.

Much more often, glass gets struck by something that causes it to break. Which was the case for my car’s sunroof – or was it?

Well, it depends on who you ask. My friend at the wheel didn’t spot the rock that was bouncing along the highway in our direction, but as a horrible passenger, my eyes are always far up the road when I’m riding shotgun, so I first spotted the rock some distance away. Beige in colour and about the size of a baseball, I figure it got pinched between some eroded roadway shoulder and the passing tire of a transport truck, which sent it airborne.

When I first noticed the flying rock, it was about 10 feet in the air and coming our way in slow motion. Bounce … into the empty oncoming lane. Bounce … into the empty oncoming lane again but much closer this time, maybe two car lengths away. I knew the rock would hit my car on its third bounce, but I didn’t know where it would strike.

The rock struck the front panel of the car’s closed panoramic moonroof, directly above my head. There was a startlingly loud BANG, almost like a firecracker, and the majority of the glass panel overhead turned into a powdery dust of glass pellets, shards, and slivers.

The rock simply bounced off and landed elsewhere, leaving no evidence behind. My friend at the wheel figured the explosion was random. Had I not happened to spot the flying rock, I would have agreed.

The Cleanup and Aftermath

Thankfully, the sunroof’s fabric sunshade was closed, which blocked most of the sharp bits from entering the car and showering both human and canine passengers with glass. The windows were open, however, which allowed plenty of the sharp dust to be sucked into the cabin where it swirled around and landed on everything and everyone, including my 8-year-old Golden Retriever in the back.

With our four-ways activated and the car pulled safely off the road, cleanup began.

Ghost was immediately evacuated to safety, some distance from the car, and cleaned off. He was unhurt. Next, my friend and I began dusting off itchy, sharp shards of glass.

I then made a glass-catching hammock to help with the cleanup. I hung an old blanket beneath the sunroof by pinching each of its four corners into place with each of the car’s power windows, and used a pocket knife to slit the fabric sunshade above to pieces, allowing the pile of broken glass on top of it to be captured easily by the blanket beneath.

With that glass contained, we bagged up the blanket in a garbage bag. Cleaning up an exploded sunroof is a disastrous mess no matter how you look at it, though I was happy the sunshade had kept most of the debris from winding up on our heads, shoulders, and laps. Broken glass gets absolutely everywhere and even after the cleanup, the drive home was still uncomfortable.

This happened at the end of the day on a Friday, but my local Volkswagen dealer came to the rescue. A quick call set me straight on the next steps: after explaining the situation, the service advisor offered to receive the car and park it inside where it would be safe and dry. They’d check things out on Monday morning. After the estimated repair costs were provided, an insurance claim was made, and a rental car was provided in the meantime.

Fixing a mess like this is a big job for the technicians and my car was out of commission for a month as parts were ordered and repairs were made. In non-COVID times, this would have been much faster, but still a huge headache to deal with.

The cost to replace the exploded glass panel on its own was about $800 plus labour, but since the retractable fabric sunshade needed to be destroyed to make the car safe to drive, replacement costs clocked in much higher. Replacing that fabric shade requires dismantling the vehicle’s ceiling, winding the new shade, reprogramming all roof mechanisms, testing, and more.

The end result was a total repair bill of over $3,000, two-thirds of which was labour.

What’s more alarming is that this isn’t the first time I’ve experienced an exploded sunroof.

Sunroofs can randomly explode, sure, but it’s more likely to shatter if struck by a freak flying rock or chunk of debris you may not notice, so it’s probably not as random as you might have read online.

I have now dealt with exploded glass on numerous occasions. I’m less worried about myself and more worried about my passengers, whether human or canine. I know how to react, what to expect, and how to protect myself if a sunroof or windshield explodes. Ghost doesn’t. Neither does my two-year-old nephew or year-year-old niece. And while we escaped our sunroof explosion without any harm in this case, I’m fairly certain I’ll never buy another vehicle with a sunroof ever again.