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San Mateo County Impervious Surfaces


Dataset Names: San Mateo County Impervious Surfaces 

Version: 2/10/2021 

Download Location: ArcGIS Online (see table 1 below) 

Credits: Golden Gate National Parks Conservancy, University of Vermont Spatial Analysis Lab, Tukman Geospatial LLC, Santa Cruz Mountains Stewardship Network, Midpeninsula Open Space District, CAL FIRE, San Mateo County Parks, San Mateo Office of Sustainability, San Mateo Dept. of Public Works, San Mateo Planning and Building Dept., San Mateo Information Services Dept., San Mateo Dept. of Agriculture Weights and Measures, San Mateo City/County Association of Governments 

Access: Publicly Available 

Appropriate Scale Range for Use: 1:1,000 and smaller 


Dataset Summary

The San Mateo County Impervious Surfaces map is a 5-class land use and land cover map of San Mateo County. The impervious map is a fine-scale polygon vector representation of all artificial impervious surfaces in San Mateo County. There are over 780,000 features in the dataset. Non-impervious areas are not mapped and are not covered by polygons. The impervious map represents the state of the landscape in summer, 2018. This data product was produced by the impervious mapping team at the University of Vermont Spatial Analysis Lab. Table 1 lists download locations for the dataset. 

Table 1. Impervious surfaces availability 



File GDB Feature Class 

ArcGIS Pro Layer Package 

Vector Tile Layer 

San Mateo County Impervious Surfaces – Selected Federal Lands

systems rulesets for impervious mapping included: orthophotography (2018), the lidar point cloud (2019), and Lidar derived rasters. 

After it was produced using Trimble Ecognition, the preliminary impervious map product was manually edited by a team of UVM’s photo interpreters. Manual editing corrected errors where the automated methods produced incorrect results. 

The impervious surfaces map reflects the state of the landscape in summer, 2018 when countywide high resolution imagery collection occurred. 

The impervious map has 5 classes, which are described below: 

Buildings – Structures above 200 square feet in area. Structures fully occluded by vegetation will not be mapped. 

Paved Roads – Roads that are paved and wide enough for a vehicle. 

Dirt and Gravel Roads – Dirt or gravel roads wide enough for a vehicle. Non-ephemeral fire roads, ranch roads and long driveways. 

Other Dirt and Gravel – Dirt or gravel surfaces that are highly compacted and used by humans and equipment, such as parking lots, road pull-offs, some dirt or gravel paths, and highly compacted areas around commercial activities. This class DOES NOT include natural turf playing fields, very lightly used dirt roads, livestock areas, naturally occurring bare soil or rock, or bare areas around ponds. 

Other Paved – Includes parking lots, sidewalks, paved walking paths, swimming pools, tennis courts. 


Miscellaneous quality control and processing notes: 

• Zoom level used during manual quality control was no finer than 1 to 500. 

• Vector data was created with no overlapping polygons. 

San Mateo County Impervious Surfaces – Selected Federal Lands

Data Limitations: 

This is not a planimetric data product and was created using semi-automated techniques. It provides a reasonable and useful depiction of impervious surfaces for planner and managers but does not have the accuracy or precision to support engineering. Appropriate uses of the data product include: 

• As an input to storm water models 

• For planners to assess % imperviousness in a parcel/watershed 

• To help identify areas of human infrastructure for fuels and fire management 

• As an input to fuel models that are used in fire behavior and fire spread models 

• For cartography and mapping 

• Generally for use at scales 1:1,000 and smaller 


Inappropriate uses of this product include: 

• Measuring exact square footage of structures or impervious features for building projects 

• Using the impervious as geographically precise information in transportation and public works 


Minimum Mapping Units: 

The table below shows the nominal minimum mapping units (MMUs) for the impervious surfaces map. Map Class 



200 square feet 

All Other Classes 

400 square feet 

Related Datasets: 

The San Mateo County Roads, Trails, and Dozer Lines feature class includes centerlines for paved and dirt roads, trails, and CAL FIRE dozer lines in San Mateo County. 

The datasheet and download links are available at 


San Mateo County Impervious Surfaces – Selected Federal Lands 

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How Santa Rosa's Tubbs fire spread, hour by hour

An analysis by The New York Times of satellite images, combined with on-the-ground surveys, provides a more complete picture of the origin, spread and devastation of the fire that killed at least 23 people in and around the city.

The Tubbs fire destroyed at least 5,200 homes and structures, shown on the map below, making it the most destructive wildfire in state history, as well as one of the deadliest. The Times analysis also shows how quickly the fire spread in the crucial initial hours.

Read a Press Democrat story about how the fire spread here and a look at the 911 calls received as the fire spread here. See all of the Press Democrat's fire coverage here.


The fire was pushed downhill at unusually high speeds by winds that sometimes exceeded 50 miles per hour. Burning embers were blown ahead of the main front, leaping ahead and igniting new fires.

In about three hours, the fire reached Santa Rosa, causing a chaotic scramble among authorities and unprepared residents.

One resident said that by the time the first emergency alert came, the flames were already marching toward his house, leaving just minutes to escape. As their city became engulfed in flames, many residents frantically fled their homes. But some people were unable to escape, and in many cases, their remains have been recovered inside or near their homes.

Sources: California Department of Forestry and Fire Protection; Sonoma County Vegetation and Habitat Mapping Program (building footprints); U.S. Geological Survey (fire perimeter); Broadcastify; National Oceanic and Atmospheric Administration; Cooperative Institute for Research in the Atmosphere; Mark Finney, Missoula Fire Sciences Laboratory, U.S. Forest Service; Neil Lareau, Department of Meteorology and Climate Science, San Jose State University; Scott Stephens, Department of Environmental Science, Policy and Management, U.C. Berkeley; Daniel Swain, Institute of the Environment and Sustainability, U.C.L.A.

By New York Times Staff Writers: Derek Watkins, Troy Griggs, Jasmine C. Lee, Haeyoun Park, Anjali Singhvi, Tim Wallace and Joe Ward.

Derek Watkins reported from Santa Rosa. Troy Griggs, Jasmine C. Lee, Haeyoun Park, Anjali Singhvi, Tim Wallace and Joe Ward reported from New York. Reporting was contributed by Susan C. Beachy and Richard Pérez-Peña from New York, Adam Nagourney from Los Angeles, and Carol Pogash from Santa Rosa.

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Camp Fire - Fire Progression Timeline

Camp Fire –Fire Progression Timeline

San Mateo County, FireSafeCouncil

Camp Fire Progression Timeline San Mateo 20211110

Camp Fire Progression Timeline Chapter 7A 20210802-pdf.pdf

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Fire Safe San Mateo November 10th: Camp Fire progression timeline

We are very lucky to have NIST’s, Alexander Maranghides present a report on the Camp Fire’s progression and time line of the fire and how the structures within the community of Paradise faired.

  • Video and Audio by computer: click this link

  • Video by computer, and Audio by phone: use the link above, then call phone number

    669-900-9128 and enter Meeting ID: 811 910 0623

  • Audio by phone only: call phone number 669-900-9128 and enter Meeting ID: 811 910



Presentation Announcement: Camp Fire _ Fire Progression Timeline Presentation Announcement_FSSMC.pdf

Presentation: Camp Fire Progression Timeline Chapter 7A 20210802-pdf.pdf

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Fire Safe San Mateo Oct 13: Pathogens and Neighborhood Alliance

Fire Safe San Mateo Oct 13 2021


  • Update and new information on pathogens and diseases affecting bay area trees and increasing our wildfire hazardous fuels.
    • Matteo Garbelotto U.C. Berkley Lab
  • The forming of a neighborhood alliance to address wildfire concerns within a community's fire prone canyons.
    • Jennifer Youstra

Video Link:

Passcode for video: t44=Fz6=


Chat Transcript ( many useful links shared by the Fire Safe Community ) tfire safe Oct

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Fire Safe Aug 11th Don Bullard - Risk Assessment & Rust Day - Why is CA Burning

Fire Safe 

Aug 11th Don Bullard

Risk Assessment & Rust Day
Why is CA Burning

Please click here to access the video recording. When prompted, use the passcode: FbA.@6BU


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AB38 - Request a Defensible Space Inspection

Beginning July 1, 2021, AB38 requires a seller of real property located in a high or very high fire hazard severity zone to provide specified documentation to the buyer that the real property is in compliance with the wildfire protection measures described above or a local vegetation management ordinance, or enter into an agreement with the buyer pursuant to which the buyer will obtain documentation of compliance, as provided.

To request an inspection for properties in the SRA (State Responsibility Area managed by CAL FIRE), use the following link:

For properties in the LRA (Local Responsibility Area), work with your Realator or contact your local fire agency for more information.


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Fire Safe San Mateo County July 14, 2021 Meeting Recording

Please use the link below to access the video recording. When prompted, used the passcode: Tu61&LMX


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Fire Safe Advisory Committee


July 13 1

July 13 2

July 13 3

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