The Glass Fire was named for Glass Mountain Road in Deer Park, Napa County, where the initial ignition occurred in September 2020.
What started the Glass Fire in California?
Investigators traced the Glass Fire’s ignition point to the 200 block of North Fork Crystal Springs Road, a location east of Silverado Trail.
No one knows for sure how it started. Cal Fire officially ruled out Pacific Gas and Electric (PG&E) equipment as a cause, though early rumors blamed downed power lines. High winds and bone-dry conditions made tracking the origin tricky, but the roadside location gave investigators their best clues.
What is meant by glass fires?
“Glass fires” refers to wildfires named after geographic landmarks, not the decorative fire glass used in outdoor gas appliances.
Here’s the confusion: “fire glass” is also that shiny tempered glass people use in backyard fire pits. In the Glass Fire’s case, the name comes from Glass Mountain Road, not any glass material. California loves this naming system—fires often get tagged after nearby roads, landmarks, or natural features.
How did Glass Fire begin?
The Glass Fire began around 4:00 a.m. on September 27, 2020, and spread rapidly due to strong winds and dry vegetation.
By sunrise, the fire had already swallowed hundreds of acres. Those 50+ mph winds acted like a bellows, sending embers flying. When containment efforts finally kicked in days later, the damage was staggering—over 67,000 acres burned across Napa and Sonoma counties. Full containment wasn’t declared until October 20, 2020. Honestly, this was one of the most destructive fires in the region that brutal 2020 season.
How did the Glass Fire start in Napa?
Embers from the Glass Fire were blown by strong winds across the valley floor, igniting smaller spot fires known as the Shady and Boysen fires.
Those secondary fires appeared the same evening the Glass Fire started—September 27, 2020. Some embers traveled over a mile, landing in dry grass and vineyards. Fire crews initially treated them as separate blazes before realizing they were all connected. That’s what made this fire so terrifyingly unpredictable.
Who started the Glass Fire?
No person or entity has been officially identified as the cause of the Glass Fire, and investigators ruled out PG&E equipment as the source.
The 38-page Cal Fire report from 2021 couldn’t pin it on arson, negligence, or even PG&E. The best guess? A spark from rocks or equipment in a canyon between two homes. No charges were ever filed. Sometimes wildfires just… start.
Is fire pit glass safe?
Yes, properly tempered fire pit glass is safe—it won’t melt, soot, or explode under normal use.
Regular glass? Not so much. It can release nasty fumes when heated and might even shatter from sudden temperature changes. Always use glass labeled specifically for fire pits—tempered glass is the only way to go. Check the manufacturer’s instructions for installation and upkeep.
How deep should fire glass be?
A depth of 1 to 2 inches of fire glass is ideal to cover the burner while keeping it hidden.
Too little, and you’ll see the burner. Too much, and you’ll smother the flames and block the heat. Spread it evenly across the burner surface—just don’t overfill. Excess glass can trap heat and damage your fire pit over time. Some people pile it high for looks, but function should come first.
What happens when glass is burned?
Burning a candle inside a sealed glass container causes the glass to fog internally and the flame to weaken until it extinguishes.
As the candle burns, it releases carbon dioxide and water vapor. Those vapors condense on the cooler inner glass, creating that telltale foggy film. Eventually, the flame runs out of oxygen and dies. If the glass cools too fast, the pressure drop can even suck the lid in or crack the glass. That’s why enclosed candle holders aren’t meant for long burns.
Is the Glass Fire still burning?
The Glass Fire was fully contained by October 20, 2020, and is no longer burning.
As of 2026, the scars remain. This fire torched over 67,000 acres and destroyed more than 1,500 structures, making it one of Northern California’s most destructive wildfires. Recovery has focused on replanting forests, restoring vineyards, and repairing roads and homes.
Where was the Glass Fire?
The Glass Fire originated in the Deer Park area of Napa County, near St. Helena, and spread into Sonoma County.
It started in a canyon between two homes off North Fork Crystal Springs Road, then raced east toward Silverado Trail. Some of the region’s most famous vineyards and wineries sat in its path. Evacuations were a nightmare—Highway 29 and Silverado Trail were both clogged with fleeing traffic.
What wineries have burned in Napa?
Among the wineries damaged or destroyed were Barnett Vineyards, Behrens Family Winery, Burgess Cellars, Cain Vineyard and Winery, and Castello di Amorosa.
This fire cut a devastating swath through wine country. Historic buildings, production facilities, and vineyards were lost. Some, like the castle-like Castello di Amorosa, suffered structural damage but were rebuilt. Others, such as Behrens Family Winery, lost parts of their facilities but managed to save their core operations. The recovery has involved rebuilding tasting rooms and replanting entire vineyards.
Will fire pit glass explode?
Wet fire glass can crack or explode when exposed to high heat, just like lava rocks.
Water inside untreated glass turns to steam under heat, building pressure until the glass shatters. Tempered glass is safer, but you should still keep it dry before lighting up. Propane fires burn hotter, so they can wear out fire glass faster. Always check for moisture or cracks before firing up your pit.
Can I mix fire glass with lava rock?
Yes, mixing fire glass with lava rock creates a visually striking contrast and enhances heat retention.
The combo blends lava rock’s earthy, rugged look with fire glass’s glossy, colorful sparkle. Lava rock spreads heat evenly, while fire glass adds that decorative pop. A typical mix is 60% lava rock to 40% fire glass, but tweak it to match your style. Just don’t go overboard on the lava rock—it can clog burner ports and kill your fire’s efficiency.
What color fire glass looks best?
Sky blue fire glass is widely considered the most visually appealing due to its reflective, gem-like quality that enhances flame visibility.
Color choice depends on your fire pit’s style and your home’s decor. Amber and emerald green bring warm, cozy vibes, while black and bronze feel sleek and modern. For a coastal feel, go with cool blues and greens. For a rustic cabin look, warmer tones work best. Always test samples in your space to see how the glass catches the light.
How much fire glass should I buy?
Purchase enough fire glass to cover the burner to a depth of 1 to 2 inches without overfilling the fire pit.
Measure your burner first. A standard 36-inch round pit usually needs 20 to 30 pounds of glass. Bigger pits may require 50 pounds or more. Buying in bulk saves money, but don’t overdo it—fire glass settles over time. Check your fire pit’s manual for exact coverage guidelines.
Edited and fact-checked by the FixAnswer editorial team.
