I just started using IFTDSS and created a small shape for a landscape of a neighborhood = 450 acres. There are 575 homes in this neighborhood, so the majority of homes are maybe 1/2 acre with lush irrigated landscapes in San Mateo County of the San Francisco Bay area.
When I run the Fire Behavior model on this landscape, it says that 51% is non-burnable with only 2% passive + active crown fire.
In other words, it looks pretty safe. Is that wrong? Is that because structures take up half the land, and the structures are considered "non-burnable" (even though obviously they are not) because they are not vegetation?
Sorry for this newbie question.
-mj lee
Best Answer
K
Kim Ernstrom
said
5 months ago
Hello MJ,
You pose a great question and glad you have found IFTDSS to help look at local fire behavior, fuel models and mapping. IFTDSS uses LANDFIRE data (LANDFIRE.gov) which includes the "non-burnable" category. The pixel size used in mapping is 30mx30m and for the most part structures are considered "non-burnable" even though as you state (and I agree) structures are indeed burnable but are not a type of vegetation so are not mapped as burnable. They are "masked out" as Wildland Urban Interface and are considered non-burnable since no wildland fire model can't account for fire behavior in a structure.
It is possible in IFTDSS to edit your landscape and change the fuel models to a different and "burnable" fuel model. This takes some insight into what the vegetation/fuel structure is in the area and it may depend on season and like you mention irrigation etc. For example, I live in Boise Idaho and for illustration purposes I wanted to show that a neighborhood near the Boise Foothills in the late summer when everything is very dry could be burnable and fire could move through a neighborhood - through the vegetation that is. So I changed some of the "non-burnable" pixels to a burnable grass model to show how fire could spread. Now this a VERY broad type of landscape edit and was used just for illustration purposes......
If you would like to read more about how the fuel and vegetation is mapped you can visit the LANDFIRE website. www.landfire.gov. also another article here that has some information:
Check out the help topic in IFTDSS on editing landscapes if you want to give that a try to see how it works. There is no official rules for editing a landscape it does take understanding of the fire behavior fuel models and understanding how these those changes affect fire behavior...
So your results that say: " 51% is non-burnable with only 2% passive + active crown fire." that is correct based on how the area was mapped. It would definitely take some interpretation and explanation to illustrate that a yard or parcel that is not irrigated could be very burnable in the dry time of the year.. so whether things are "safe" or not is quite dependent on local conditions.
another good case study is the Marshall Fire in Colorado or the recent Lahaina Fire in Maui - if you looked at how those areas were mapped it would probably be similar to what you are seeing in your example... we know as a fact that these Urban Interface areas are very vulnerable... hence the need for fire behavior expertise and interpretation of the modeling outputs by folks with experience in this field.
You pose a great question and glad you have found IFTDSS to help look at local fire behavior, fuel models and mapping. IFTDSS uses LANDFIRE data (LANDFIRE.gov) which includes the "non-burnable" category. The pixel size used in mapping is 30mx30m and for the most part structures are considered "non-burnable" even though as you state (and I agree) structures are indeed burnable but are not a type of vegetation so are not mapped as burnable. They are "masked out" as Wildland Urban Interface and are considered non-burnable since no wildland fire model can't account for fire behavior in a structure.
It is possible in IFTDSS to edit your landscape and change the fuel models to a different and "burnable" fuel model. This takes some insight into what the vegetation/fuel structure is in the area and it may depend on season and like you mention irrigation etc. For example, I live in Boise Idaho and for illustration purposes I wanted to show that a neighborhood near the Boise Foothills in the late summer when everything is very dry could be burnable and fire could move through a neighborhood - through the vegetation that is. So I changed some of the "non-burnable" pixels to a burnable grass model to show how fire could spread. Now this a VERY broad type of landscape edit and was used just for illustration purposes......
If you would like to read more about how the fuel and vegetation is mapped you can visit the LANDFIRE website. www.landfire.gov. also another article here that has some information:
Check out the help topic in IFTDSS on editing landscapes if you want to give that a try to see how it works. There is no official rules for editing a landscape it does take understanding of the fire behavior fuel models and understanding how these those changes affect fire behavior...
So your results that say: " 51% is non-burnable with only 2% passive + active crown fire." that is correct based on how the area was mapped. It would definitely take some interpretation and explanation to illustrate that a yard or parcel that is not irrigated could be very burnable in the dry time of the year.. so whether things are "safe" or not is quite dependent on local conditions.
another good case study is the Marshall Fire in Colorado or the recent Lahaina Fire in Maui - if you looked at how those areas were mapped it would probably be similar to what you are seeing in your example... we know as a fact that these Urban Interface areas are very vulnerable... hence the need for fire behavior expertise and interpretation of the modeling outputs by folks with experience in this field.
Great question - thank you for reaching out
Kim
IFTDSS Team
MJ Lee
said
5 months ago
Thanks for the detailed reply. It is too bad that LANDFIRE uses such a misleading term, as it makes it harder to share the map with homeowners. big at the rate that property intelligence is advancing, maybe in a few years there will be sufficient data and technology to calculate the fire spread and flammability of structures.
So should I stop using IFTDSS for a WUI suburb like my town Portola Valley? Even with 1-3 acre parcels, it seems like the structures could really misconstrue the results. And, I am not qualified to do those tweaks you suggest.
K
Kim Ernstrom
said
5 months ago
There are many different definitions of the Wildland Urban Interface, it is definitely not a one-size fits all term. One has to keep in mind that LANDFIRE is always referring to fuels and vegetation - never structures, so in that sense it isn't necessarily misleading - it is quite accurate according to the way they define their mapping rules. I can understand your confusion on the "burnable vs non-burnable" in the very literal sense however.
There is work going on in the engineering and structural fire world that is modeling the "flammability in the Built-environment" as it is called... but that work and the wildland fire modeling do not mix at the current time.
The best practice would be to review fire behavior in the wildlands surrounding the housing areas and show what the fire behavior would be adjacent to the homes.. this could inform the subdivisions and homeowners how flammable or not the non-residential areas are.
I would caution using these outputs without have the expertise to understand the assumptions of these fire models. I agree with you that the results could be very misleading when not interpreted correctly with a background in fire behavior. You could reach out to the local fire protection district - or the county or agency that manages the land closest to your neighborhoods and ask about any Wildland Fire Risk Assessments that have been completed for the area.
Thank you again for reaching out - it is possible that others visiting our Forum have a similar question and can participate in this discussion.
-Kim
IFTDSS Team
MJ Lee
said
5 months ago
Hi Kim,
Sorry for all the emails and thank you for your willingness to help. I understand that LANDFIRE is not trying to be misleading with their use of th term "non-burnable", and that IFTDSS is merely reporting LANDFIRE results.
I meant to say that the average homeowner could easily misconstrue a graphic like the one I've attached, which is from one of the IFTDSS reports I generated. The homeowner would say they have no problem. So from that perspective, I would not show these reports to them. However, I will try to figure out how to show them fire spread or flame length on neighboring wildland. That might be the best use of IFTDSS for my purposes.
MJ Lee
I just started using IFTDSS and created a small shape for a landscape of a neighborhood = 450 acres. There are 575 homes in this neighborhood, so the majority of homes are maybe 1/2 acre with lush irrigated landscapes in San Mateo County of the San Francisco Bay area.
When I run the Fire Behavior model on this landscape, it says that 51% is non-burnable with only 2% passive + active crown fire.
In other words, it looks pretty safe. Is that wrong? Is that because structures take up half the land, and the structures are considered "non-burnable" (even though obviously they are not) because they are not vegetation?
Sorry for this newbie question.
-mj lee
Hello MJ,
You pose a great question and glad you have found IFTDSS to help look at local fire behavior, fuel models and mapping. IFTDSS uses LANDFIRE data (LANDFIRE.gov) which includes the "non-burnable" category. The pixel size used in mapping is 30mx30m and for the most part structures are considered "non-burnable" even though as you state (and I agree) structures are indeed burnable but are not a type of vegetation so are not mapped as burnable. They are "masked out" as Wildland Urban Interface and are considered non-burnable since no wildland fire model can't account for fire behavior in a structure.
It is possible in IFTDSS to edit your landscape and change the fuel models to a different and "burnable" fuel model. This takes some insight into what the vegetation/fuel structure is in the area and it may depend on season and like you mention irrigation etc. For example, I live in Boise Idaho and for illustration purposes I wanted to show that a neighborhood near the Boise Foothills in the late summer when everything is very dry could be burnable and fire could move through a neighborhood - through the vegetation that is. So I changed some of the "non-burnable" pixels to a burnable grass model to show how fire could spread. Now this a VERY broad type of landscape edit and was used just for illustration purposes......
If you would like to read more about how the fuel and vegetation is mapped you can visit the LANDFIRE website. www.landfire.gov. also another article here that has some information:
https://vcs.pensoft.net/article/67537/
Check out the help topic in IFTDSS on editing landscapes if you want to give that a try to see how it works. There is no official rules for editing a landscape it does take understanding of the fire behavior fuel models and understanding how these those changes affect fire behavior...
So your results that say: " 51% is non-burnable with only 2% passive + active crown fire." that is correct based on how the area was mapped. It would definitely take some interpretation and explanation to illustrate that a yard or parcel that is not irrigated could be very burnable in the dry time of the year.. so whether things are "safe" or not is quite dependent on local conditions.
another good case study is the Marshall Fire in Colorado or the recent Lahaina Fire in Maui - if you looked at how those areas were mapped it would probably be similar to what you are seeing in your example... we know as a fact that these Urban Interface areas are very vulnerable... hence the need for fire behavior expertise and interpretation of the modeling outputs by folks with experience in this field.
Great question - thank you for reaching out
Kim
IFTDSS Team
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Sorted by Oldest FirstKim Ernstrom
Hello MJ,
You pose a great question and glad you have found IFTDSS to help look at local fire behavior, fuel models and mapping. IFTDSS uses LANDFIRE data (LANDFIRE.gov) which includes the "non-burnable" category. The pixel size used in mapping is 30mx30m and for the most part structures are considered "non-burnable" even though as you state (and I agree) structures are indeed burnable but are not a type of vegetation so are not mapped as burnable. They are "masked out" as Wildland Urban Interface and are considered non-burnable since no wildland fire model can't account for fire behavior in a structure.
It is possible in IFTDSS to edit your landscape and change the fuel models to a different and "burnable" fuel model. This takes some insight into what the vegetation/fuel structure is in the area and it may depend on season and like you mention irrigation etc. For example, I live in Boise Idaho and for illustration purposes I wanted to show that a neighborhood near the Boise Foothills in the late summer when everything is very dry could be burnable and fire could move through a neighborhood - through the vegetation that is. So I changed some of the "non-burnable" pixels to a burnable grass model to show how fire could spread. Now this a VERY broad type of landscape edit and was used just for illustration purposes......
If you would like to read more about how the fuel and vegetation is mapped you can visit the LANDFIRE website. www.landfire.gov. also another article here that has some information:
https://vcs.pensoft.net/article/67537/
Check out the help topic in IFTDSS on editing landscapes if you want to give that a try to see how it works. There is no official rules for editing a landscape it does take understanding of the fire behavior fuel models and understanding how these those changes affect fire behavior...
So your results that say: " 51% is non-burnable with only 2% passive + active crown fire." that is correct based on how the area was mapped. It would definitely take some interpretation and explanation to illustrate that a yard or parcel that is not irrigated could be very burnable in the dry time of the year.. so whether things are "safe" or not is quite dependent on local conditions.
another good case study is the Marshall Fire in Colorado or the recent Lahaina Fire in Maui - if you looked at how those areas were mapped it would probably be similar to what you are seeing in your example... we know as a fact that these Urban Interface areas are very vulnerable... hence the need for fire behavior expertise and interpretation of the modeling outputs by folks with experience in this field.
Great question - thank you for reaching out
Kim
IFTDSS Team
MJ Lee
Kim Ernstrom
There are many different definitions of the Wildland Urban Interface, it is definitely not a one-size fits all term. One has to keep in mind that LANDFIRE is always referring to fuels and vegetation - never structures, so in that sense it isn't necessarily misleading - it is quite accurate according to the way they define their mapping rules. I can understand your confusion on the "burnable vs non-burnable" in the very literal sense however.
There is work going on in the engineering and structural fire world that is modeling the "flammability in the Built-environment" as it is called... but that work and the wildland fire modeling do not mix at the current time.
The best practice would be to review fire behavior in the wildlands surrounding the housing areas and show what the fire behavior would be adjacent to the homes.. this could inform the subdivisions and homeowners how flammable or not the non-residential areas are.
I would caution using these outputs without have the expertise to understand the assumptions of these fire models. I agree with you that the results could be very misleading when not interpreted correctly with a background in fire behavior. You could reach out to the local fire protection district - or the county or agency that manages the land closest to your neighborhoods and ask about any Wildland Fire Risk Assessments that have been completed for the area.
Thank you again for reaching out - it is possible that others visiting our Forum have a similar question and can participate in this discussion.
-Kim
IFTDSS Team
MJ Lee
Hi Kim,
Sorry for all the emails and thank you for your willingness to help. I understand that LANDFIRE is not trying to be misleading with their use of th term "non-burnable", and that IFTDSS is merely reporting LANDFIRE results.
I meant to say that the average homeowner could easily misconstrue a graphic like the one I've attached, which is from one of the IFTDSS reports I generated. The homeowner would say they have no problem. So from that perspective, I would not show these reports to them. However, I will try to figure out how to show them fire spread or flame length on neighboring wildland. That might be the best use of IFTDSS for my purposes.
Thanks again,
-mj lee, volunteer
Portola Valley Wildfire Preparedness Committee
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