Firewise How To Q&A: an interview with Jack Cohen, offering perspective on current wildland fire conditions

Blog Post created by faithberry Employee on Feb 3, 2016

Dr. Jack Cohen was among the featured presenters at last fall's Backyards & Beyond Conference, held in Myrtle Beach, South Carolina. He highlighted his research results, which he has shared with NFPA’s Firewise Communities for many years. As we chatted privately, he discussed his insights on current fire conditions and what homeowners can do in the event of a wildfire to create a safer environment for those they love. While at times the news about the intensity of current wildfires and associated home destruction is grim, following my interview with Dr. Cohen I was encouraged by the fact that homeowners can make a difference.

I asked Dr. Cohen what he noticed about the change in intensity of wildfires in recent years and if he had ideas about what might be causing those changes. 

He responded, “I think we have a problem with wildfire in the wildland/urban interface (WUI) and ecologically without climate change. Climate change may be generating persistent patterns of dry conditions laid on top of a dramatic reduction in the historic fire occurrence under all weather conditions.

There is a change in the frequency and intensity of wildland fires from historical occurrence 150 years ago. Scientists estimate that the annual burned area on average was on the order of 70-105 million acres per year under all conditions that would spread fire. These figures are adjusted for land use in the lower 48 states. The current average for acres burned per year is much less, around 5 million acres. This is more than 10 times less than historically occurred. But today a significant portion of the 5 million acres burns under extreme conditions and that has dramatically changed the frequency and conditions of fire as an appropriate ecological factor. We need to keep in mind that fire has been a principal factor in the development of most ecosystems since the end of the Pleistocene Age.”

I shared with Dr. Cohen that I had seen many reports about recent wildfires that seem to indicate that there is little hope for individuals to protect their property and loved ones from wildfire. I asked him, with current fire conditions as extreme as they are, can changes made to the home and landscape immediately surrounding the home really make a difference?

Jack said, “The research I have done indicates, ABSOLUTELY! This is possible because the home ignition zone (HIZ), that area that includes the house in relation to the fire brand exposure and immediate surroundings within 100-200 feet principally determines the home’s ignition potential under extreme conditions; thus, we need not control the uncontrolled extreme wildfire to prevent the WUI fire disaster. HIZ Diagram

All research that I have done is in the context of extreme fire behavior. The disastrous fires I’ve examined have all been in extreme fire behavior conditions. We should not confuse the inability to control wildfire with an inability to prevent a residential fire disaster. 

While wildfire is inevitable and wildfire under extreme conditions is inevitable, wildland/urban interface (WUI) fire disasters need not be inevitable.”