Yosemite West Property & |
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In May 2004, the Mariposa County Fire Department conducted a Geographical Information System (GIS) survey of Yosemite West whose purpose was to identify and rank which structures they can safely defend and which structures they cannot in the event of fire.
The survey gathered the following data about structures and infrastructure:The processed data gave a numerical and color-coded Hazard Value for each property. The numerical value ranges from 1 to 150. Four color-coded zones illustrate the risk: green zone (least risk), yellow zone (some risk), orange zone (more risk), and red zone (extreme risk). MCFD manually cross-checked the calculations of each Hazard Value weighing structure design, maintenance and fuel loading. The data also produced a color-coded community map and individual homeowner reports. The reports included a list of steps homeowners can take to improve their rating.
MCFD's policy is not to commit firefighters and equipment to any structure classified in the Red Zone, so the goal of the community and MCFD is to have zero properties in the Red Zone.
The 2004 Red Zone Survey for Yosemite West (see table) showed only 24% of structures were in the target zone (Yellow Zone) and that 76% of structures were in undesirable high-risk zones (Red Zone and Orange Zone). Structures in the high-risk zones required immediate action by homeowners. No property in Yosemite West is the Green Zone. MCFD's ideal goal is to have every Red Zone and Orange Zone property improved to the Yellow Zone. MCFD is available to the community to help make this goal a reality.
| 2004 Red Zone Fire Risk Assessment Results | ||
|---|---|---|
| Color-coded Zone | Actual % of Structures per Zone | Goal % of Structures per Zone |
| Green Zone | 0% | 0% |
| Yellow Zone | 24% | 100% |
| Orange Zone | 64% | 0% |
| Red Zone | 12% | 0% |
The Red Zone Fire Risk Assessment is not a static survey. Rather it needs periodic updatings as property owners take action to improve their Hazard Values and as new houses are built.
Mariposa County Fire Department (MCFD) conducted the first Red Zone Fire Risk Assessment of Yosemite West in 2004. A second Red Zone Survey was conducted in August 2008 with funding provided by a National Fire Plan grant awarded to YWPHI from the National Park Service through the California Fire Safe Council.
MCFD compiled the 2008 survey results (using the RedZone Software program) and generated a 2008 Red Zone Survey report for each house in Yosemite West, which was mailed to homeowners on November 15. (Property reports for some Henness Circle area and Henness Ridge Road homeowners and for those who constructed houses after 2004 have not yet been mailed, but will be sent in spring 2009.)
The survey data yields a numerical Hazard Value ranging between 1 (the lowest risk) to 150 (the highest). These numerical values correspond to color-coded zones illustrating the risk: Green Zone (least risk), Yellow Zone (some risk), Orange Zone (high risk), and Red Zone (extreme risk).
| 2008 Red Zone Fire Risk Assessment of Yosemite West | |||||
|---|---|---|---|---|---|
| Hazard Zone | Hazard Value | 2004 Survey % of Structures | 2008 Survey % of Structures | Change | Goal |
| Green | 0-34 | 0% | 0% | 0% | 0% |
| Yellow | 35-69 | 24% | 23% | (1%) | 100% |
| Orange | 70-104 | 64% | 57% | (7%) | 0% |
| Red | 105+ | 12% | 20% | 8% | 0% |
The 2008 Red Zone Survey for Yosemite West shows only 23% of structures are in the target zone (Yellow Zone) and that 77% of structures are in high-risk zones (Red Zone and Orange Zone). Structures in the high-risk zones require immediate action by homeowners. No property in Yosemite West is in the Green Zone. Here are some key points from the survey.
•The highest (most risk) Hazard Value is 139, with five houses higher than 120, and more than 20 houses in the Red Zone.The Mitigation Notes towards the end of the reports are an educational tool designed to be a to-do list to improve your Red Zone Hazard Value. No matter what zone your property is in, everyone can improve.
Everyone will know their current Hazard Value and color-coded zone and know what specific steps they can take to improve it. Working to improve your Hazard Value and color-coded zone will also work towards compliance with the state law requiring 100-feet of Defensible Space from structures.
Mariposa County Fire Department generally will not commit firefighters and equipment to any structure classified in the Red Zone, hence, it is in everyone's interest to have zero properties in the Red Zone.
YWPHI and the MCFD are planning to repeat the survey in summer 2009 as a measureable outcome of success of our new fire safety grant, so please contribute your effort to lower your Hazard Value. Thank you for supporting our efforts to create communitywide defensible space and make Yosemite West a Fire Safe community.
The Red Zone Fire Risk Assessment of Yosemite West was first conducted in 2004 and a second assessment was conducted in 2008. The assessment identifies and ranks structures that the fire department can safely defend, so the MCFD's goal is to have every house in the higher risk Red and Orange Zones improve to the Yellow Zone.
| 2009 Red Zone Fire Risk Assessment of Houses in Yosemite West | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Hazard Zone | Hazard Value | Risk Level | 2004 | 2008 | 2009 | Goal | Change 2008 to 2009 | # Structures in 2008 Survey | # Structures in 2009 Survey |
| Green | 0 - 34 | Least | 0% | 0% | 0% | 0% | 0% | 0 | 0 |
| Yellow | 35 - 69 | Some | 24% | 23% | 40% | 100% | 17% | 25 | 53 |
| Orange | 70 - 104 | High | 64% | 57% | 51% | 0% | (6%) | 61 | 69 |
| Red | 105 + | Extreme | 12% | 20% | 9% | 0% | (11%) | 21 | 12 |
| Total: | 107 | 134 | |||||||
Here are some key points from the 2009 Red Zone Fire Risk Assessment. The data clearly demonstrates that everyone who participated in the 2009 defensible space project improved their Hazard Value whereas nonparticipants showed zero improvement. We will be targeting the latter for participation in the 2010 defensible space project.
| 2009 Red Zone Fire Risk Assessment Overview | 2008 | 2009 | Change for Participants | Change for Non-participants |
|---|---|---|---|---|
| % 2009 defensible space project participants whose Hazard Value improved | 100% | 0% | ||
| % total homeowners whose Hazard Value improved | n/a | 37% | 37% | 0% |
| # houses in Red Zone | 21 | 12 | 9 fewer | 0 |
| % houses in the high-risk Red and Orange Zones still requiring action by homeowners (goal = 0%) | 77% | 60% | 17% fewer | 0% |
| # houses in Yellow Zone | 25 | 53 | 28 more | 0 |
| % houses in Yellow Zone (goal = 100%) | 23% | 40% | 17% more | 0% |
| median Hazard Value (decrease = improvement) | 79 | 75 | (4) | 0 |
| average Hazard Value point improvement | 13 | 0 | ||
| median Hazard Value point improvement | 7 | 0 | ||
| most improved Hazard Value point improvement | 51 | 1 | ||
| % of total homeowners whose Hazard Value remained the same or worsened (yes, you can ignore the trees, but they keep growing) | 0% | 48% | ||
| # houses remaining in the Red Zone | 21 | 12 | 0 | 12 |
| # newly constructed houses since 2004 in high-risk Red and Orange Zones | 0 | 4 | ||
| highest (most risk) Hazard Value | 139 | 139 | 99 | 139 |
| % houses with less than 100 feet of defensible space and not in full compliance with PRC§4291, the state law requiring 100 feet of defensible space from structures | n/a | 70% | ||
| % houses with vegetation near the roof (i.e., branches within 5 feet, overhanging branches, and/or debris on the roof itself) that needs to be removed | 76% | 70% | 6% decrease | |
| # houses without adequate defensible space | n/a | 94 | ||
| % houses that do not have or have only non-reflective street address signage visible at street level | 63% | 51% | 12% decrease | |
Note: Not all of the 2009 participant houses achieved the goal of creating adequate defensible space. The reasons for this shortfall include property owners flagging ladder fuels as "Do not cut", branches within 5 feet of the structure and more than 15 feet above ground beyond the project's scope, and large dead trees on property.
The Red Zone Fire Risk Assessment focuses on parcels with houses. There is no equivalent assessment for vacant parcels. However, fuel reduction on vacant parcels is essential for structural protection and communitywide defensible space.
Please direct any inquiries about the Red Zone Surveys to Deputy Fire Chief Jim Middleton, tel: (209) 966-4330, email: jmiddleton@mariposacounty.org.
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 Copyright text © Yosemite West Property & Homeowners, Inc. 2003-2012, Copyright photographs © John Mock 2004-2012. All rights reserved. Unauthorized redistribution of this document is prohibited. Updated February 7, 2012. |