The nonprofit Wildfire Collaborative Roaring Fork Valley has been using an advanced model to map wildfire risk in several communities.
Marble, Snowmass Village and the Three Mile and Four Mile neighborhoods of Glenwood Springs recently received those results and Aspen and Carbondale will have them in the coming months.
Dr. Hussam Mahmoud developed the wildfire model at Colorado State University in 2022, after realizing that existing models couldn’t accurately predict how fire moves through communities.
Mahmoud, who now works at Vanderbilt University, spoke to Aspen Public Radio’s Michael Fanelli about what the results are showing for the Roaring Fork Valley and how he would approach them.
The conversation below has been edited for clarity and length.
MF: What are you finding so far? What are you seeing in these results?
HM: So one of the things that I've noticed is that: Do we have a wildfire problem in the Roaring Fork Valley? Absolutely. Is it as bad as California? No. And when I talk about as bad as California, I'm talking about the extreme events in California that we've seen. So when we run the analysis and we look at the vulnerability score, which implies a likelihood of damage for each building in the community, I am finding that Snowmass or Marble or Three Mile, Four Mile, Glenwood area, it's definitely less than events that we've seen in California. And definitely less than the Marshall Fire, also. The other thing that becomes interesting is that we try to develop optimal mitigation. So we go back and say, “Okay, now that we know what we know in terms of the vulnerability,” we work with the stakeholder to try to drop the vulnerability to an acceptable level. So when we agree on that acceptable level, the question is: how do we get there? Well, we're able with our models to come up with the most optimal mitigation, and that includes fuel management and home hardening if needed. And the reason why I'm saying if needed is because fuel management is easier to implement, right? It's much easier to say “We're gonna thin the fuel” than knock on homeowners and say “You need to change the siding. You need to do this.”
MF: Some of those homes that are the high risk and are the biggest priority to address, in some cases, the owners of those homes are going to be uninterested or unwilling to address that risk. How should we approach those situations?
HM: Actually, I was working on a paper. The title is "The Social Dilemma of Superspreaders in a Wildfire Event.” So I've been thinking about it quite a bit. So there's a reason why when we look at the vulnerability, we look at the average across the community. That's one of the reasons. It's because I don't want to go to a homeowner and say, "Aha! You are high vulnerability. You are a bad person. I need to drop you down.” I'm just saying, “I'm gonna drop the mean for the whole community.” And these buildings that act as superspreaders aren't necessarily the buildings that have bad siding or bad roofs or have trees next to them — not necessarily. It's actually really cool. The model identifies superspreaders. These superspreaders are homes that, if they burn, then fire will spread much faster. These homes might be homes that have high vulnerability, high likelihood of burning. It could actually be a home that has low vulnerability. The implication there is that while it's less likely for that home to burn, if it burns, hell will break loose. And so then those homes that have likelihood of burning and those homes that have likelihood of spreading. So if I'm gonna target homes for mitigation, I would want to target the ones that score high on both. They’re highly likely going to burn and also super spreaders.
MF: One other thing I was curious about that you said earlier, that our local communities here are relatively lower risk than places in California, and I think you said the Marshall Fire. I'm just curious why that is?
HM: A huge part of it is the moisture content in the vegetation. Now of course that could change in the future right, if things continue to worsen, but so far we are not getting the heavy dry condition that California sees. We're also not seeing the same wind conditions that California sees. And sure, we have high wind, but we don't have the Santa Ana winds. We don't have the Lahaina hurricane-type wind that scooped across Lahaina. We're not seeing that. Obviously the Marshall fire had very high wind cases. But even if you look at the 100th percentile wind for areas like Marble or Snowmass or Three Mile, Four Mile, so far, it’s substantially less. And the topography has a lot to do with how that wind gets downscaled on the landscape. So you have the wind coming in, but then you have a lot of kind of peaks and valleys in the area that kind of break down that wind.
MF: Well this has been a fascinating conversation and I've learned a lot. I really appreciate you taking the time, Hussam.
HM: Absolutely. Thank you for the invitation and for the wonderful questions.
