Product

The results of this analysis are summarized by USFS unit PODs and are intended to be used as a treatment or suppression prioritization tool. The output represents wildfire transmission risk from USFS PODs to HVRAs. The following HVRA values from the 2024 PNW QWRA were used: People and Property, Drinking Water, and Infrastructure.

POD transmission output in geodatabase format is provided for each HVRA individually and as a combined weighted product according to relative importance from the QWRA. The output transmission values are provided as normalized values between -1 and 1 for prioritization at the unit level, and raw values for potential prioritization across units. Products are provided both clipped and unclipped to the forest boundary. Features which are clipped to the forest boundary were done so post transmission analysis calculation. Quantiles are the recommended symbology type when viewing results.

Data

The analysis utilizes fire simulation output data from the 2024 PNW QWRA conducted by Pyrologix including the ignitions and associated perimeters from the Large Fire Simulator (FSIM), as well as the HVRAs weighted conditional net value change (cNVC) grid data processed by Oregon State University. For more details on the PNW QWRA data, refer to the 2023 PNW QWRA Methods Report for full details: https://oe.oregonexplorer.info/externalcontent/wildfire/PNW_QWRA_2023Methods.pdf

Methods

PODs are obtained from the National Potential Operational Delineations (PODs) Public feature service (https://www.arcgis.com/home/item.html?id=cc50b6ca69734e4180d5399006058e58). Unit administrative boundaries were obtained from the USFS feature service. PODs which intersect the unit administrative boundary are used for analysis.

For each analysis POD, ignitions within the POD are selected and associated with their corresponding perimeters to obtain those perimeters which originated within the POD.

HVRA zonal statistics are performed on each perimeter regardless of land ownership or analysis area boundary, to obtain the ignition/perimeter sum cNVC. The sum cNVC per ignition (perimeter sum) is then divided by the total number of FSIM ignition simulations to normalize values across Pyrum.

Finally, the sum cNVC per ignition iteration is summed by POD, multiplied by ten thousand (majority of Pyrum simulations) to rescale the value, divided by the total number of ignitions within the POD to normalize across PODS, and then rescaled again between -1 and 1 (zero centered).