Flash flood fatalities in New South Wales, Victoria, Australian Capital Territory and South East Queensland from 1 January 2000 to 30 June 2017

This report analyses the circumstances surrounding fatalities resulting from flash flood events in New South Wales (NSW) from 1 January 2000 to 30 June 2017, and also from Victoria (Vic), the Australian Capital Territory (ACT) and South-east Queensland (SEQld ) in order to inform emergency management policy. The foundation for this work is Risk Frontiers’ natural hazards database PerilAUS, and the National Coronial Information Service. At least 130 flash flood fatalities have occurred in NSW, Vic, ACT and SE Qld from 1 January 2000 to 30 June 2017. Some of the more salient results found were that: 

Numbers and death rates 

• raw numbers of annual flash flood deaths are not decreasing 
• the NSW death rate shows a constant trend from 2000-2017, while male death rates trend upwards and female deaths downwards 

Gender and age 

• males represent 66% of flash flood fatalities 
• there are increasingly more male than female deaths occurring 
• age groups most at risk are 10-19 then 60-69 and 70-79 
• males in the 10-19 age group are dramatically over-represented 
• a large increase is seen in deaths amongst the 60-69, 70-79 and 40-49 age groups over time 

Location and severity 

• most fatalities occurred in the Brisbane River Drainage Basin 
• Pine, Hawkesbury and Hunter river basins had the next most fatalities 
• most deaths have occurred within a few drainage basins; there is also a wide spread of deaths across the areas studied 
• most deaths (44%) have occurred in floods of a minor to moderate severity, correlating with the numbers of events of that severity 

Cause of death 

• most fatalities were caused by drowning or a mix of drowning/ injury 
• isolation due to floodwaters can be a contributing factor in fatalities 

Warnings, awareness, visibility 

• despite clear signals of rain/ flood hazard and warnings, especially in the case where people are in the vicinity of watercourses, some people still make poor decisions in the case of flash floods, such as attempting to drive across 
• most (60%) decedents driving a vehicle through floodwaters were killed during darkness 
• 73% of those who died while attempting to cross floodwaters did so within 20km of their home, and 53% within 2km of home 

Activity prior to death 

• 54% were attempting to cross a stream, creek or other watercourse: 67% of those male
• 9% of fatalities were in/ near a stormwater drain, the majority males and half of those aged 10-19: fewer such deaths have occurred in the more recent time period 
• 8% of fatalities were engaged in a recreational activity in floodwater: fewer have occurred in the more recent time period 

Type of Transport 

• 52% of decedents had driven through or up to floodwaters 
• the majority of drivers and passengers were males 
• the most common age groups amongst vehicle-related deaths were 60-69 and 70-79 
• 25% of decedents were on foot and fewer of these deaths occurred in the more recent time period 

Flash flood casualties who died in their home 

• all 20 individuals who died in their home did so during 2009-2017 and in severe or record events where three or more persons died 
• there were equal numbers of males and females 
• most (70% of) decedents were aged 50-89 

Reason behind action prior to death 

• a “business as usual” attitude persists: in the majority of cases the decedent, having started out en route somewhere, persisted, despite floodwaters 
• most deaths were amongst males, most en route home and most from recreation or non- essential shopping 
• recreation was also a common activity amongst decedents: mainly males aged 10-19 
• equal proportions of males and females were involved in the third most common activity: being in/ near homes 

Multiple-fatality events 

• Half of the flash flood fatalities were single-fatality events 

Severity of event versus activity 

Most deaths have occurred in severe/ record flood events amongst those who were: 

• in or on a house or structure – 100% 
• attempting to evacuate (from home or work, or attempting a vertical evacuation at home) – 44% (with the remainder divided equally amongst major and low-moderate floods) 
• taken by surprise, with no attempt at/ very late evacuation – 100% 

Most deaths have occurred in low-moderate flood events amongst those who were: 

• engaged in an activity in/ near stormwater drain – 81% 
• recreating – 75% 
• attempting to cross a causeway/ watercourse – 59%