NFPA Journal

IN 2015, the nation’s largest fire in terms of direct property loss was a wildland/urban interface fire that occurred in California. Three days after that fire began, the next-biggest large-loss fire of the year broke out—also a wildland/urban interface fire and also located in California. Both of these fires ranked among the most costly in the state’s history. Combined, the fires destroyed thousands of homes and other structures, were blamed for at least six deaths, and resulted in a loss of almost $2 billion dollars. These fires rank as the second- and fourth-largest wildfire losses in the state in the past 10 years.

The larger fire was known as the Valley Fire. It began in the early afternoon in September, the result of an improperly wired hot tub on the rear porch of a private single-family dwelling. Dry grass and leaf litter in contact with the connection ignited. At the time the fire broke out, the temperature was 88 degrees F (31.1 degrees C), relative humidity was 12 percent, and winds were 18 mph (29 kph), with gusts to 30 mph (48.3 kph). The entire area had had drought conditions for nearly 48 months. The fire was originally reported as a two-acre (0.8-hectare) grass fire. Within five hours, the fire had grown to over 10,000 acres (4,047 hectares) and in another five hours grew to 25,000 acres (10,117 hectares). By early October, when it was 100 percent contained, the fire had grown to 76,067 acres (30,783 hectares), destroyed 1,280 single-family homes, 27 multi-family homes, 66 commercial properties, and 585 minor structures (including sheds and other small structures).

Numerous vehicles were also destroyed. Another 93 structures of various sizes and types were damaged. At times, the flame heights reached 100 feet (30 meters) and massive evacuations were ordered to keep residents safe.

At least four people lost their lives in the fire area. In addition, 77 firefighters were injured, including four who were trapped in their initial attack on the fire; they deployed their emergency shelters and survived but received serious burn injuries. The cost to fight this massive fire was $56 million. The estimated property loss, as reported by insurer Aon Benfield, was $1.5 billion.

Three days later, the second fire, known as the Butte Fire, broke out in the early afternoon when a tree came in contact with electrical power lines. This contact caused sparks and embers to fall and ignite fine dead and dry fuels. From that point, the fire grew rapidly in weather conditions similar to those at the Valley Fire. By evening, the fire had spread from 100 acres (40 hectares) to 14,500 acres (5,867 hectares) and reached 32,000 acres (12,949 hectares) in two days. By early October, when the fire was contained, it had burned 70,868 acres (28,679 hectares) and destroyed 965 structures, of which 475 were homes, and was responsible for at least two deaths. The estimated loss in this fire, as reported by insurer Aon Benfield, was $450 million. Very erratic fire conditions were noted by fire officials during both the Butte and Valley Fires. For more information on wildfires in 2015, see “The Year in Wildfire” in the November/December 2015 NFPA Journal.

The Valley Fire, a wildfire in California, was the nation's costliest large-loss fire, tallying an estimated $1.5 billion in losses. Photograph: Reuters images

NFPA reports annually on large-loss fires and explosions that occurred in the United States the year before, defined as an event that results in property damage of at least $10 million. There were 27 such fires in 2015, with a total of over $2.5 billion in direct property losses. In order to compare losses over the past 10 years, we adjust losses for inflation to 2006 dollars. When adjusted for inflation, the number of fires in 2015 that would have been categorized as large-loss fires—that is, fires resulting in a loss of $10 million in 2006 dollars—drops to 17, with an adjusted loss of slightly more than $2 billion.

According to “Fire Loss in the United States During 2015,” published in the September/October issue of NFPA Journal, U.S. fire departments responded to an estimated 1,345,000 structure and non-structure fires, which caused an estimated loss of $14.3 billion. Many of these fires were small or resulted in little or no reported property damage. Although the 27 large-loss fires accounted for only 0.002 percent of the estimated number of fires in 2015, they accounted for 18 percent of the total estimated dollar loss. In addition, those 27 fires accounted for 19 civilian deaths, with another five civilians and 80 firefighters injured, some critically.

With the two wildfires mentioned above, 2015 was the ninth year out of the past 10 that a wildfire topped the list of the year’s biggest large-loss fires. In two of those years, 2011 and 2015, wildfires were the largest and second-largest fires, and in 2007 the three largest fires were wildland fires. In the past 10 years, there have been 36 wildland fires that accounted for more than $10 million in direct property losses. In human terms, these fires have been responsible for 73 deaths, including 32 firefighters, and $7.4 billion in loss to property.

In 2015, 10 fires—five fewer than the previous year—resulted in more than $20 million each in property damage. These fires included six in structures, three wildfires, and one aircraft fire, resulting in a combined property loss of $2.3 billion, or 92 percent of the total loss in large-loss fires and 16 percent of the total fire losses in the United States for 2015.

Where fires occurred

Of the 27 large-loss fires in 2015, 20 involved structures that resulted in a total property loss of $464.1 million, or 18 percent of the combined losses for all large-loss fires. The other fires included five wildland/urban interface fires and two vehicle fires that resulted in combined losses of $2.1 billion, or 82 percent of the losses in all the large-loss fires. Both vehicles were aircraft: a military jet on takeoff for a test flight and a business jet.

Seven fires occurred in manufacturing plants: a glass manufacturing plant, a fertilizer plant, a silkscreening plant, a metal plating plant, a metal products plant, a meat processing plant, and a grain processing plant, causing a combined loss of $185.7 million.

Four large-loss fires occurred in residential properties, including two apartment buildings, a 70-unit hotel, and a single-family home, causing a combined loss of $58.8 million.

A business jet crashed into a four-unit apartment building in Ohio, killing all nine people aboard the aircraft and resulting in an estimated $11 million in losses. Photograph: AP/Wide World

Two fires each occurred in storage properties (a book warehouse and an appliance parts warehouse), public assemblies (a church and a county administration building), and special properties (a vacant warehouse and a commercial structure under renovation), resulting in combined losses of $120 million, $41 million, and $23.6 million, respectively.

One fire each occurred in the categories of industry (an electrical transformer), educational (an elementary school), and stores and offices (an office building), resulting in losses of $14 million, $11 million, and $10 million, respectively, for a combined loss of $35 million.

Cause of ignition was reported for 10 of the 27 fires, including six of the structure fires. Two of the structure fires were caused by cutting or welding operations too close to combustibles, two were due to a mechanical failure, and two were reported as due to electrical failures of unknown type. One of the vehicle fires was due to a fire following a collision and the other to a leak in an oxygen line caused by a loose coupling. One of the wildland fires was due to an installation deficiency and another to natural conditions, where winds caused a pine tree to come into contact with energized power lines.

The operating status was reported for 14 of the 20 structure fires. In seven cases, the facility was open and operating, with six at full operation and one in partial operation. Seven were closed and the properties were unoccupied. Seven of the fires involving structures broke out between 11 p.m. and 7 a.m. These fires had a direct property loss of $215.6 million.

Detection and suppression systems

Information about automatic fire or smoke detection equipment was reported for 14 of the 20 large-loss structure fires. Four of those fires occurred in properties that had no automatic detection equipment installed. Of the systems in the other 10 structures with information reported, eight systems operated as designed. In two of the cases, it was not reported whether or not the system operated.

Information about automatic suppression equipment was reported for 15 of the 20 structure fires. Ten had no system present and five structures had some type of system. In two cases, the systems operated as designed, but the fire department reported the systems were ineffective. In one of the two cases, the fire broke out in rack storage; the sprinklers above the racks operated, but water could not reach the seat of the fire. No reason was given in the other case. In another fire, the system did not operate—it had been shut down prior to the fire. Information on the operation of the suppression systems in the other two fires was not reported.

Of the 14 structures for which the presence of both detection and suppression equipment was reported, three had neither an operational detection system nor an operational suppression system. Both types of systems were operational in four fires. Six structures had only detection equipment, and one included only suppression equipment.

What we can learn

There was one more large-loss fire in 2015 than in 2014, with an increase in associated property losses of $1.8 billion. This is in large part due to two massive wildland/urban interface fires in 2015 with a combined loss of almost $2 billion. In nine of the past 10 years, at least one fire resulted in a loss of more than $100 million. In 2015, there were three such fires: two wildfires and an appliance parts warehouse. Over the past 10 years, there have been 24 fires with more than $100 million in losses, including two with more than $1 billion in losses. Of these largest of losses, 12 were wildland/urban interface fires, 10 were structure fires, and two were vehicle fires. The two $1 billion losses were wildfires. The only year in the past 10 in which the highest dollar loss fire was not a wildland fire was 2014.

It is evident that climate conditions around the country have played a role in large-loss fires. Four of the five wildfires this year were in California, where there has been a four-year drought, and it was reported that the drought situation was a factor in the fires.

Adhering to the fire protection principles reflected in NFPA’s codes and standards is essential if we are to reduce the occurrence of large-loss fires and explosions in the United States. Proper construction, proper use of equipment, and proper procedures in chemical processes, storage, and housekeeping will make fires less likely to occur and help limit fire spread should a fire occur. Proper design, maintenance, and operation of fire protection systems and features can keep a fire that does occur from becoming a large-loss fire.

Where we get our data; acknowledgements

NFPA identifies potential large-loss incidents by reviewing national and local news media, including fire service publications. A clipping service reads all U.S. daily newspapers and notifies NFPA’s Fire Analysis and Research Division of major large-loss fires. NFPA’s annual survey of the U.S. fire experience is an additional data source, although not the principal one. Web searches have proved useful in several cases where fire department and government reports have been released and published.

Once a fire has been identified, we request information about it from the fire department or agency having jurisdiction. We also contact federal agencies that have participated in investigations, as well as state fire marshals’ offices and military sources. The diversity and redundancy of these data sources enables NFPA to collect the most complete data available on large-loss fires.

This report includes only fire incidents for which NFPA has official dollar-loss estimates. There are other fires that may have large losses but no official information has been reported to NFPA.

NFPA would like to thank the U.S. Fire Service for its contributions of data, without which this report would not be possible. In some cases, the fire department, forestry officials, or government officials were unable to contribute complete details to NFPA because legal action is pending or ongoing, the incident was of a sensitive nature, or the size of the situation was overwhelming. The author also wishes to thank members of NFPA staff for providing the support this study requires.

STEPHEN BADGER, a fire data assistant with NFPA’s Research Division, is retired from the Quincy, Massachusetts, Fire Department.