BOGOTA – Wildfire Investigation

Bogota. I was a little apprehensive about what I would find in this city. It seemed to be low on the list of places to visit on the backpackers itinerary of Columbia. In fact many used it purely to fly in and out of and spent little time exploring. So it was a joy to find out the city was so much more than expected. The cool climate was a significant relief from the sweaty experience of the north (a key factor in why this FireTreks article has taken so long!).

IMG_20190626_144529045_HDR-min
The colourful streets of La Candelaria

The colourful crowded streets of La Candelaria steeped in history, culture and good food led me to the impressive Simon Bolivar Square, where the Palace of Justice is located. It was a sobering site considering the lessons I’d previously learnt regarding the siege that took place here in 1985, where a fire ripped through the building not only destroying it but many of the artefacts and documents inside.

 

 

The city is relatively flat but with surrounding hillsides – the most dominating of which is Monserrate which provided a panoramic view of the city. The vista allowed for a true appreciation for the vastness of Bogota and the contrasts from other cities I’d visited so far.

IMG_20190702_153446763-min
Bogota as seen from Monserrate Hill

I went to visit William Cabrejo of Bogota Fire Department who introduced me to the international cooperation team to find out more about the city. Once again it was wonderful how welcoming the fire department were and how much time they were willing to spend explaining what their team has to offer. The meetings organised for me included the Fire Departments Chief Director Pedro Manosalva, who presented information on Bogotas’ firefighters, facilities and the challenges that were faced in the city.  Among the group were chiefs of two of the larger stations in Bogota and specialists from fire investigation and wildfire departments. It was a real honour, and the enthusiasm and passion which was so readily felt in Medellin was definitely maintained here.

IMG_20190705_100249-min
Bogota Fire Departments Chief Director Pedro Manosalva presenting

Through our discussions it was apparent that regardless of how different Medellin and Bogota appeared, similar issues were mirrored. Again, enforcement of fire safety regulations was proving difficult  in poorer areas where new people were migrating into the city and building illegal housing.

New laws were introduced in 2012 to help regulate the implementation of fire safety across all departments.

⦁ Law 1505 (Volunteering)
⦁ Law 1523 (Disaster Risk Management) and
⦁ Law 1575 (Firefighters)

With 26 fire departments and around 2000 fire fighters made up of both employed and volunteers, Bogota is considerably larger than other Colombian cities. One thing that did strike me was that the scope was not just limited to buildings but also included 14,000 hectares of forested areas. Some of the stations have therefore been set up with equipment and vehicles to deal with the threat of wildfires including specialist protective suits, masks and helmets.

Wildfires are a fascinating subject for me, having spent my whole career dealing with cities , I was intrigued to find out more about the issues posed by wildfires and how Bogota deals with this threat based on its unique environment.
As the issue of wildfires becomes more and more relevant particularly in the realms of climate change I will touch on this subject more and more as the journey continues. For this article my focus is on one particular aspect of wildfires – post fire investigation. How and why fires start, how investigators analyse points of origin and what measures are being introduced to prevent them from happening again.
For obvious reasons, wildfires occur more often in the dry seasons between December to February and June to August each year, as high temperatures and low rainfall, coupled with more intense winds increase the risk. Bogota can see a lower number of fires compared to other parts of Colombia based on its altitude.

William Diaz, a specialist in fire investigation, highlighted that around 80% of the wildfires that were investigated in the region were down to Arson or man made causes.

San Cristobal
Wildfire pictured from the San Cristobal district of Bogota (provided by Bogota FD)
Monseratte
Air support provided for a wildfire on Monserrate Hill (provided by Bogota FD) 

Following any fire, the investigation team moves in to determine the area of origin which is integral to correctly identifying the cause.

As with other areas of fire engineering, aspects of wildfire investigation are open to interpretation and results can vary depending on who is carrying out the investigation. I have read a number of articles that highlight issues of misinterpretation when it comes to investigative practices. If mistakes are made, this could lead to incorrect conclusions that may result in the prosecution of innocent parties.

Bogota uses the NFPA 921 Guide for Fire and Explosion Investigations to assess the path of fire and determine the point of origin. Chapter 28 provides a basic introduction to the processes required to determine a timeline of events. It is a fascinating read and it is clear why varying results could be interpreted because so many variables can effect the development of the fire.

Here is Chapter 28 of NFPA 921 in a nut shell….

Fuel
An initial understanding of the fuels which were present is integral to analyse the behaviour of the fire as individual elements will produce different burning characteristics. Logs, leaves, dry twigs, hanging moss, grasses etc are classified depending on their physical characteristics –
⦁ are they on the ground, surface or aerial?
⦁ are they grass, shrub, timber or logging debris?
⦁ what is the species, size, form and arrangement of the fuel load?
⦁ how large an area do they cover?
⦁ are they dead or alive?
Once these factors are determined, the rate of spread (or resistance) can be assessed and along with topographic and weather conditions the general behaviour of fires can be determined.

Bogota is currently facing an issue with a plant not indigenous to the area. ‘Retamo Espinoso’ which directly translates to ‘thorny reed’ is a type of gorse that was brought over from Europe in the 60’s to form natural protective fences. This plant is a pyrophyte, aka it loves fire. Not only does it cause rapid fire spread, it generates high temperatures, toxic smoke and gases. Fire can also speed the germination process which means it can regenerate quickly post fire and dominate other indigenous plant life. In other words its a big headache for Bogota Fire Department!

Topography
The topography will affect the intensity and spread of the fire. If a slope is present, fuel on the ‘upper’ section will be heated more rapidly as the distance between the flame and the fuel is decreased, allowing the fire to burn more intensely and rapidly. The slope may also cause burning debris to roll back down the hill and create secondary fires.
The aspect of the slope will also contribute to ignition potential or vegetation characteristics since the slopes facing the sun will be typically drier.

Weather
The temperature of the ambient air will also influence the fuel temperature, which is why Bogota’s altitude is a positive i.e. the higher the altitude, the lower the air pressure which allows the air to expand and cool. Other weather effects include relative humidity, wind velocity, cloud cover and precipitation.
Weather data for Bogota (both historical and forecasting) is collected from IDEAM (Institute of Hydrology, Meteorology and Environmental Studies) and IDIGER (District Institute of Risk Management and Climate Change) as well as the Ministry of Environment.

Indicators
The process reads like a puzzle where the investigator follows each ‘clue’ as part of a trail of evidence back to the source. Indicators range from soot deposits, charring (with the angle of the char being an integral tell based on slope and wind direction), leaf curling, white ash deposit, staining, spalling and general degree of damage. When foliage is heated it becomes pliable and leans in the direction of prevailing winds or drafts, as they cool they ‘freeze’ in the direction to again provide a vital tell.

But it’s not always simply following the above rules. Foliage freezing will usually indicate fire direction but at times it does not when other factors are considered. Fire spread can also be influenced further through human intervention or natural mechanisms which can throw the interpretation off. An example of this include embers, or animals and birds burnt in the fire causing secondary fires. Consequently, the code stresses that a single indicator should not be relied upon for a decisive conclusion, all indicators should be considered as part of a holistic review which is why expert eyes are needed to decipher them.
The investigator can also build a picture of the wildfire through the accounts of eye-witnesses, first responders and crew members.

Causes
Causes of wildfires can be classified as accidental, natural, induced or undetermined. As mentioned previously a significant proportion of wildfires in Bogota are the result of arson. Other causes seen in Bogota include –

  • Fireworks
  • Beekeeping
  • Hunting
  • Recreational activities
  • Burning in the agricultural environment
  • Smoking
  • Burning garbage
  • Burning other materials (tires, cables, etc.)

Bogota FD have clear plans to reduce wildfire occurrence and as always, education is a key factor. It was great to see that some of the conclusions I had come to in Medellin regarding actively engaging young people in the area was being carried out here. The scheme ‘Club Bomberitos’ or ‘Little Firefighters Club’ aims to educate future generations in fire safety to aid community and environmental/wildfire safety. Additionally, in the short term, the existing 7 wildfire stations will be enhanced with new equipment and more personnel.  Long term, new training schemes are also being developed

There are also plans to obtain drones which will enable aerial visuals to be easily taken. This would allow V-shaped burn patterns to be viewed (which are affected by wind and slopes). As the width of the pattern increases from the place of ignition, it can be a useful way of identifying the point of origin.

I have learnt a lot from Bogota and I am eager to use this new found knowledge through the rest of my journey. Next up I will be visiting Cali and the ecological restoration team who deal with regenerating environments post fire.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s