Community Risk Assessment

This report serves as a supplement to the Fairfax County Fire and Rescue Department’s (FCFRD) “Integrated Risk Management Plan: “Standards of Cover” document. The Commission on Fire Accreditation International ( CFAI ) defines the process known as “deployment analysis” as a written procedure which determines the distribution and concentration of fixed and mobile resources of an organization. The purpose for completing this document is to assist the FCFRD in ensuring a safe and effective response force for emergency medical services (EMS), fire suppression, and specialty response situations. This document conforms to the Center for Public Safety Excellence’s (CPSE) 10 ^th  edition Commission on Fire Accreditation International (CFAI) model.

The creation of this Standards of Cover was a collaboration internally and with external stakeholders and required that a number of key areas be researched, studied, and evaluated. The report begins with an overview of both the community and the fire service. Following this overview, the agency will discuss areas such as risk assessment, critical task analysis, agency service level objectives, and distribution and concentration measures. The FCFRD will provide documentation of reliability studies and historical performance through charts and graphs. This report concludes with policy recommendations.

Fairfax County Fire and Rescue Department is an “All-Hazards” Department providing emergency medical response, fire suppression, technical rescue, hazardous materials response, fire inspections, public education, investigation, and community training and education. The FCFRD strives to provide the highest quality services to protect the lives, property, and environment of our community. Currently the FCFRD is maintaining accreditation through the Commission on Fire Accreditation International.

As part of the re-accreditation process through the Center for Public Safey Excellence (CPSE), agencies must define “risk” within the communities they serve to best fit their response model, through continuous improvement, to eliminate, reduce, or prepare an effective recovery to unmitigable risk. This document explains the process by which variables were identified and weighted to define probability (of occurrence), consequence (to the community), and impact (to the agency) as they determine overall risk.

All data queried for this assessment were stored in a static database to shelter it from updates, creating a snapshot of the data used for this analysis. Supporting documents are housed in the Data Analytics and Strategy Management Microsoft Team.

 NOTE: The COVID-19 global pandemic began to have a significant regional impact in March 2020, affecting call handling, call volume, and response by all public safety agencies.

At the incident level, each incident was given a value of (1), denoting its occurrence.

At the first due level, probability was defined as the proportion of all incidents within a service line during each calendar year which occurred within each first due.

At the incident level, each incident was weighted by variables known to indicate criticality and were tailored to each service line. These columns were computed from data points taken from the computer-aided dispatch (CAD) system and the FCFRD’s records management system (RMS) for electronic patient care reports (ePCR) and National Fire Incident Reporting System (NFIRS) reports. The sum of each variable was stored as the total, or weighted, Consequence represented by the incident. Except for total patients transported, civilian deaths, and percent property lost, each variable is binary with a value of (1) denoting its occurrence. Civilian deaths were multiplied by (3) to intensify the impact to the community of the loss of life and its potential secondary impacts such as loss of household income, loss of caretaker, loss of business revenue, etc.

 The variables used to weight incidents within each service line are outlined below:

EMS:   

• ALS (Advanced Life Support) care provided to one or more patients (0/1) + (determined by medications and procedures)
• total patients transported +
• first dispatch to first arrived longer than 300 seconds (0/1) +
• only non-first due units dispatched (ambulance, medic, engine, truck, rescue) (0/1)

Fire:       

• Rapid Intervention Team (RIT) dispatched (0/1) +
• percent property loss +  
• structure fire (0/1) +
• total patients transported +
• civilian deaths (multiplied by 3) +
• repeat structure fire at the same address in the last 12 months (0/1) +
• first engine arrival on a fire-dispatched call longer than 320 seconds (0/1) +
• only non-first due units dispatched (ambulance, medic, engine, truck, rescue) (0/1)

HazMat:

• percent property loss +
• total patients transported +
• only non-first due units dispatched (ambulance, medic, engine, truck, rescue) (0/1)

Rescue:

• percent property loss +
• total patients transported +
• only non-first due units dispatched (ambulance, medic, engine, truck, rescue) (0/1)

Unit hour utilization (UHU) was applied as a proxy for Impact. Computed at hourly increments, UHU is calculated as the proportion of time (seconds) that a unit is marked out of service or on a call (dispatch to clear) of the total time (seconds) the unit is logged on in CAD. UHU figures were aggregated by calendar year, fire station, and unit type and stored as decimal percentages.

To calculate and meaningfully stratify Risk, the CPSE formula for a three-pronged risk model was utilized and a z-score computed to determine each first due’s deviation from the average risk within each year and service line as well as within the same service line across all five years. Within the risk score table, for each year, first due, and service line, the individual probability, consequence, and impact scores were carried over from the first due aggregations. Additionally, Risk was calculated using the formula below along with the average risk, standard deviation from those averages, and resulting z-score within each year and service line as well as within the same service line across all five years.

The final Risk category for each first due and service line was determined by discrete percentiles; such that “low” risk first dues were those whose Risk score was less than or equal to the 33 ^rd  percentile, “moderate” risk first dues were those whose Risk score was greater than the 33 ^rd  percentile and less than or equal to the 66 ^th  percentile, and “high” risk first dues were those whose Risk score was greater than the 66 ^th  percentile. 

Fire station 444 was opened in September 2021, however the first due was added as a data point as early as 2020 to allow the field to become familiar with the fire boxes. As such, risk calculations for first due 444 were not calculated until calendar year 2022.

Climatological risk due to metrological events are regional events that cross neighboring jurisdictional boundaries. During these events, agencies within Northern Virginia operate under automatic aid to provide the closest resource to the service demand.

Source: 2022 Northern Virginia Hazard Mitigation Plan, Draft

From 1950 through 2021, the National Centers for Environmental Information (NCEI) has maintained records of previous flood events within their Storm Events Database.  There have been reports of 406 flood events in Fairfax County during this timeframe.  Of these events, 3 were categorized as coastal flood/storm surge events, 174 as flash flood events, 23 were attributed to heavy rain, 202 as floods, and remaining 4 as Tropical Storms. Historically, flood events have caused serious damage that has altered emergency response, affected public transportation, and citizens’ way of life.

Between 1996 and 2021, the NCEI Storm Events Database has documented severe winter weather events (including blizzard, heavy snow, ice storm, winter storm, and winter weather). Within that period, there have been 503 winter storm event reports, causing an estimated $1.025 million in property damage in the Northern Virginia Region.  Fairfax County has recorded 148 winter storm events during this timeframe.

Between 1950 and 2021, the NCEI Storm Events Database has documented high wind and severe storm events. Since severe storms are difficult to predict, it is extremely difficult to determine probability of future occurrence with any degree of accuracy. It can, however, with considerable confidence, based on historical record, be projected that Northern Virginia will continue to experience severe thunderstorms with great frequency – several times a year, in most cases.  Fairfax County has experienced 595 high wind/severe storm events during this timeframe.

Risk, defined as probability multiplied by impact, cannot be fully estimated for tornadoes due to the lack of intensity-damage models for this hazard. While tornadoes are most common in the central and southeastern parts of the country, Virginia has seen its fair share of twisters. In fact over the last decade, Virginia has averaged 24 tornadoes per year. 

Since 1972, Fairfax County has experienced 20 tornadoes, including touchdowns in:

• Tysons in 2022
• Centreville in 2022
• Reston in 2019
• Lincolnia in 2018
• Herndon in 2017
• Belle Haven in 2014

Source:  Guide to Tornado Preparedness in Fairfax County | News Center 

From 1950 through 2018, the National Climate Data Center (NCDC) reports describe six occurrences of tropical storms impacting Fairfax County. These tropical storms caused more than $18.2 million in property and crop damages, one fatality, and one injury. Heat Emergencies While this hazard occurs with some regularity, it is not one with a significant history of causing damages or losses to property in the Northern Virginia region. The risk of exposure and negative health impacts to people, animal, and agriculture are the greatest risk, with the risk to the loss of utility service (particularly electrical) also a consideration. Humans and animals can be injured or die from exposure to both extreme cold and extreme heat; agriculture can be damaged or destroyed by extremes in temperature, rending crops unusable. Utility systems may fail under strains of demand, resulting in increases in exposure of humans and animals to extreme temperatures, as facilities cannot provide regulated temperatures and climate.

The risk associated with drought in Northern Virginia has not been formally quantified, due to the difficulty in assessing the rate of incidence, and the lack of complete data on drought impacts. There is low risk of human injury/death due to drought in Northern Virginia, and low risk of property damage. Crop damages due to drought are uncertain, as agricultural productivity often varies with growing conditions from year to year.

The FCFRD evaluates risk across four major services lines: EMS emergency, fire, rescue, and hazmat. The following maps illustrate cross-county risk within each service demand zone for each service line, symbolizing the risk percentile and magnitude relative to other service demand zones.