Early Friday morning, about 20 hours after the Marshall Fire ignited, a drone operated by Twitter user WxChasing/Brandon Clement flew over subdivisions that were devastated by the December 30 fire. It found block after block of ash piles, some still smoldering. In many scenes there was scarcely a structure still standing. (Scroll down to see the video.)
To see all articles on Wildfire Today about the Marshall Fire, including the most recent, click here: https://wildfiretoday.com/tag/marshall-fire/
All of the reasons why some houses did not burn even though dozens around them were consumed could not be determined from the video, but there was one common feature — the survivors were more distant from the neighboring homes. Many houses in the subdivisions were only 10 to 20 feet apart based on archived imagery in Google Earth.
Each little square was a beautiful home 24 hours ago. #MarshallFire #wildfire #COwx #wx #superiorfire pic.twitter.com/Mp8CbyxVRw
— WxChasing- Brandon Clement (@bclemms) December 31, 2021
The fire was driven by very strong winds gusting at 60 to 100 mph, extremely dry conditions after months of drought, and relative humidity in the mid-20s. These are the very worst fire conditions. The weather paired with the nearly back to back structures led to the fire spreading through a continuous human-made fuel bed. When one house burned the convective and radiant heat easily ignited its neighbor, which ignited its neighbor, etc.
The fire in the vegetation and structures lofted burning materials far downwind, creating distant spot fires in the home ignition zone on bone dry lawns, mulch beds around ornamental plants, and on structures. It is unknown at this point how many had been designed and built to be fire resistant, such as the characteristics of the roof, vents, siding, doors, windows, foundation, fences, eaves, and decks. A FEMA publication (13 MB) has excellent detailed recommendations. Headwaters Economics found that the cost of building a fire-resistant home is about the same as a standard home. Local building codes could regulate these features. But if the lot size is so small that residences are only 10 to 20 feet apart, if one becomes fully involved, the neighbors also burn, especially during windy conditions.
So far we have listed some factors that affect the vulnerably of structures during a wildland-urban interface fire: home spacing and lot size, the envelope of the structure itself, fire codes, and the home ignition zone. Others are:
- Evacuation capability and planning;
- Safety zones where residents can shelter in place;
- Road and driveway width, wide enough for large fire trucks;
- Turnarounds at the end of roads;
- Signage, and;
- Emergency water supply.
The video below of the Marshall Fire devastation was shot by WxChasing/Brandon Clement at first light on December 31, 2021, the day after the fire started. Not long after, snow began falling. The National Weather Service in nearby Boulder recorded an accumulation of eight inches.
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13 thoughts on “Photos show devastation after the 6,000-acre Marshall Fire in Colorado”
My husband has said for years that houses are built too close together. His “rule” is that you should be able to tip each house on its side and not touch the next house. Looks a lot better, too!
One news broadcast mentioned shake roofs as more flammable than asphalt. Asphalt is basically thick oil.
It doesn’t matter how far apart they are. When winds are 60 – 100 mph, spot fires start, embers land on roofs, land on tree trops, travel and the fire can start up anywhere. In that case it wont matter if your home is spread out from others. Has your husband been USFS Hotshot FireFighter, Helitak, Smoke Jumper at one time.
Actually, it does….. certainly does not guarantee that hot fire brands will not start other structures on fire, but 100 feet or more of spacing would have dramatically reduced the damage. In this case radiant heat was the main driver once structures at the head of the fire ignited. I’ve worked enough fires in the wild land / urban interface to understand this behavior. The Troublesome fire in Grand County, CO showed this type of patchwork burning – some structures burned, but many spared. Good structure spacing allowed us to get resources in without too much danger to firefighters – we could identify safe zones and radiant heat build-up was not overwhelming.
A shake Shingle roof is basically a pile of tinder but are cheap. They are often treated with chemicals to make them water and mold resistant, which further dries them out. Asphalt shingles are less likely to catch fire when an ember lands on them and require no maintenance, however the best roof is a metal roof which can resist direct flame impingement, embers and burning sticks. Zoning laws and building regulations are needed to limit fire danger and flammability. Where there are no rules, it all comes down to what is cheapest and can make the developer the most money. For more information on making your property resistant to fire, go to; firewise.org
Boulder Office of Emergency Management
JANUARY 1, 2022, 2:19 PM ALERT
Sheriff Joe Pelle has updated the latest damage assessment numbers related to the Marshall Fire. Total numbers are 991 structures destroyed and 127 damaged. Here are the local breakdowns:
Destroyed – 553
Damaged – 45
Destroyed – 332
Damaged – 60
• Unincorporated Boulder County:
No shakes in these neighborhoods. All were architectural asphalt shingles. Higher end homes for the most part.
I can’t remember how long it’s been since I’ve seen a shake roof in metro Denver. Most local building codes ban them here
Quite a few roofs, including my in-laws’, in northwest Lakewood have shakes. I agree that they are a bad idea.
The City of Boulder years ago issued a mandate to help protect residents from fire. This mandate requires that homes within the City of Boulder with a roof consisting of more than 50% wood by volume MUST BE REPLACED by January 1, 2014. Eight years ago.
Absolutely spacing made a difference. Developers want to maximize profits on cheap land.
Look at infill housing. Lot line setback requirements have been gutted. Now you have traumatized families with gutted neighborhoods
Everyone happy in the free market unregulated communities?
High end housing is made of rock stone brick and block NOT petroleum products.
Basically these houses were built in high risk areas and marketed to those who wanted to say they lived in Colorado. Now?
Stop giving out mortgages and homeowners insurance when this much stupidity is in play. Same for flood zones.
In my neck of the woods you can’t get home owners insurance with shake roofs.
Proximity of fuels is a serious factor in the spread of fires. If people build big houses on their little bitty lots, (as the building industry, taxing authority, lenders and the real estate promotors pressure them to do) they collectively create an unsafe environment for fire. The cultural and community dynamics call for changes in the markets and building codes.. he realtors, however, would howl!
The data on the distance between homes and the spread of fire is important. In some areas, single family zoning has been abolished and the construction of a second home on an existing small lot is encouraged. Your data would seem to indicate that this practice may increase death and construction. IMO, you should feature this information is a separate article which does not seem to be about photographs. People and communities need guidance about how far apart to space homes and other structures.
At about 1:16 in the video, you can see one house standing unburnt. It appears to be located at 985 Arapahoe Circle in Louisville and the neighborhood is just south of Harper Lake. It is on a corner that is directly to the NE of the intersection of Arapahoe and Willow Place. It’s a great example of not being immediately adjacent to another structure in the direction of wind flow, which was coming from the SW at that time. My daughter and her family live in Superior in the Rock Creek neighborhood. Fortunately their home and others around it were spared, mostly because the wind moved to the SE only at the end of the afternoon. Homes there along Eldorado Drive that backed the open space were destroyed, while homes across the street to the north survived due to wind direction and fuel availability (dry grass and brush). All of the destroyed homes along Eldorado were $1M+ structures, backing the open space with large wooden decks. Wood fences line the entire neighborhood and were mostly ignited when these homes burned.
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