Estimated Ground Evac Time

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Last updated on 7/28/2023 2:06:18 PM.

Estimated Ground Evac Time Overview

This layer contains the estimated ground transport time in hours from every point within the Continental United States (CONUS) to a definitive care facility (hospital). This data includes both walking speeds when traveling off-road and driving speeds according to the speed limit of the roads traveled. The intent of this layer is to initiate discussions regarding Agency Administrator risk tolerance and mitigation as it pertains to firefighter safety at the earliest possible opportunity in the decision making process. It is not intended to automatically deter resource deployment to any location, but to encourage thoughtful decisions about the risks being transferred to firefighters and how to mitigate those risks. This layer contains several assumptions including, but not limited to, the following:

• The estimate does not include the time it might take to get critical care resources to the injured employee or the time to stabilize and package the employee for transportation.
• The travel time estimate is from the moment a litter is lifted off the ground and travel begins.
• The estimate does not address the fitness of the litter crew and their ability to maintain a constant rate of travel.
• It assumes a constant rate of speed and does not account for stops for patient care or litter crew handoffs.
• It assumes an ambulance or similar mode of vehicle transportation is waiting at the closest point on a road from the injury location to begin driving immediately.
• It uses estimated rates of travel across various topography and the covering fuels.
  

Estimated Ground Evac Time Data Input

Provided here is a National mosaicked dataset derived from regional raster analysis and converted to a vector polygon dataset identifying four travel time bands: 1-2 hours, 2-4 hours, 4-6 hours and 6+ hours to the nearest hospital.

EVT - Landfire Existing Vegetation Type. National. Version 1.0, Public Use. Reclass raster data based on "NVCS" (National Vegetation Classification Standard) Order" and "EVT Name" found in this table.

NVCS Order Value	Reclass Value
Herbaceous/Nonvascular-dominated	Grass
N/A	Non-burnable
No Data	NoData
No Dominant Lifeform	Non-burnable
Non-vegetated (not EVT "open water")	Non-burnable
Non-vegetated (EVT "open water")	Water
Shrub-dominated	Brush
Tree-dominated	Timber

Slope - USGS Elevation Derivatives for National Applications (EDNA). 2006. Public Use. Reclass raster data using this table.

Value	Reclass Value
No Data	NoData
0 to 10 Degrees	Flat
11-30 Degrees	Moderate
Greater than 30 degrees	Steep

Matrix - Reclass unique combinations of EVT Reclass and Slope Reclass grid values using this table. The data was converted to hours/meter for use in the calculations.

	NoData	Grass	Brush	Timber	Non-burnable	Water
NoData	NoData	NoData	NoData	NoData	NoData	NoData
Flat	NoData	(3mph) hours per meter	(1.5mph) hours per meter	(.75mph) hours per meter	(3mph) hours per meter	(.01mph) hours per meter
Moderate	NoData		(1.5mph) hours per meter	(.75mph) hours per meter	(.25mph) hours per meter	(2mph) hours per meter
Steep	NoData	(1mph) hours per meter	(.5mph) hours per meter	(.1mph) hours per meter	(1mph) hours per meter

Streets - Navteq. Septemer 2010. Version 2010.2. For Official Use Only (FOUO); no other use constraints. Any use of the data provided by NAVTEQ requires a copy right notice. © NAVTEQ - All rights reserved. Polyline data converted to raster grid conforming to matrix cell size, grid, projection and mask. Reclass value based upon speed category using this table.

Value	Data Dictionary Range	Selected Value	Reclass Value
1	65-80mph	70mph	0.00000887673132 hours per meter
2	55-64mph	60mph	0.0000103561865 hours per meter
3	41-54mph	50mph	0.0000124274238 hours per meter
4	31-40mph	40mph	0.0000155342798 hours per meter
5	21-30mph	30mph	0.0000207123731 hours per meter
6	6-20mph	15mph	0.0000414247461 hours per meter
7	Less than 6 mph	5mph	0.000124274238 hours per meter

Cost Raster - Calculate cost raster values from Matrix and Streets grids using Cell statistics (minimum overlay statistic.) The resulting unit is hours per meter.

Hospital - TechniGraphics, Inc. (TGS). February 2010. For Official Use Only (FOUO). Point data converted to raster grid conforming to cost raster cell size, grid, projection, and mask. Excluded urgent care clinics and clipped this layer to the US States layer to exclude Canadian and Mexican hospitals to get at "definitive" care.

Process: Applied the Cost distance algorithm in ArcGIS10 using the hospital grid and cost raster. The result is a 30m grid of CONUS with ground transport time to the nearest hospital.

Converting the raster data to WFDSS-ready vector data (post processing):

1. The cost-distance grid data were reclassified into bins based on travel times:

Value Range	Reclass Values
0-1	NoData
1.000001-1	2
2.000001-2	4
4.000001-6	6
>6	7

1. The binned cost-distance data were resampled to 90 meter resolution using the "Majority" resample technique.
2. The resampled data were passed through a majority filter four times using a replacement threshold of "Half" in order to smooth the dataset and remove the "salt and pepper" character typical of raster datasets. This step reduces the complexity of the vector polygons and improves performance in WFDSS. Analysis showed that for large areas typical of fire planning areas (50 acres or more), majority filtering does not substantially skew summary results.
3. A 90-meter mask grid of water areas was created using open water polygons in the ESRI2010USA detailed water (dtl_wat), excluding polygons classified as FTYPE "Inundation Area", "Playa", or "Swamp/Marsh. Areas of open water in the mask layer were reclassified as NoData to remove water areas from the layer.
4. The resulting 90-meter binned layer with water masked out was converted to unsimplified vector polygons for ingestion into WFDSS.

Estimated Ground Medvac Time Disclaimer

Use constraints: This dataset is provided "as is" without warranty of any kind, including, but not limited to, the implied warranties of merchantability and fitness for a particular purpose. User must assume responsibility for determining the suitability of these data for their purposes.

Estimated Ground Evac Data Limitations

This dataset is to be used in planning and implementation phases of an active wildfire. This dataset is meant to quantify what many practitioners know qualitatively about the remoteness of many of the lands we manage. Our highest priority is to manage for the safety of the public and our firefighters. This dataset can help ensure that we have taken the proper steps to ensure a timely response should a serious accident occur. These data are an estimate of the ground transport time to a fixed set of hospitals and should not be used for real-time route finding or specific evacuation routes.

There is a known issue with these data surrounding large water bodies. Due to some discrepancies with the processing of the data there are frequently small polygons in the 6+-hour bin that typically appear to the north and east side of lakes/ponds/large water bodies. These polygons represent a slight limitation in the dataset and were determined to not have a significant negative effect on the intent of the dataset. These polygons are a known limitation and will be addressed in future data updates.

Estimated Ground Evac Data Information

Data Source:	National Park Service NIFC
Extent:	National
Projection/Datum:	Projection/Datum
Data Download:	Spatial Data Downloads

 

WFDSS GIS Team

The WFDSS application is "data rich". It requires data which is spatially oriented and graphically displays information to support wildland fire and other natural resource decisions. Due to the type and number of interagency spatial data sets required in April 2009 an interagency GIS Team was formed to provide data support for WFDSS. This Team is responsible for acquiring, consolidating, and validating their agency spatial and tabular data. In addition this team developed and maintained communications among local, regional, and national agency personnel to improve the collection process and provide explicit guidance on data needs. The members of the WFDSS GIS Team are:

Table 1: WFDSS GIS Team

WFMRD&A Amanda Rumsey Data Scientist 208.830.0160 send email	WFMRD&A Jonah Vaughan GIS Specialist 406.531.4702 send email	WFMRD&A Susan McClendon GIS Specialist 208.258.4244 send email
BLM - AFS Jennifer L. Jenkins GIS Specialist 907.356.5587 send email	BLM - NIFC Julie Osterkamp Natural Resource Specialist 801.520.8702 send email	BIA - NIFC Joseph Kafka Fire Management Specialist 208.387.5572 send email
NPS - NIFC Skip Edel Fire - GIS Program Lead 303.969.2947 send email	USFS - NIFC Cole Belongie Data Coordinator 208.488.5246 send email	USFWS - NIFC Andrew Bailey National Fire Planner 208-387-5345 send email