In late January and early February 2017, low pressure systems in the north of Western Australia generated notable cloud bands from atmospheric moisture. As a tropical low from the north moved over the Pilbara coast on 8 February; a cloud band brought widespread rain to the state's south-west.
From 8-11 February, daily rainfalls exceeding 50 millimetres were reported. Parts of the Lower West, including Perth and the Great Southern, received 100-150 millimetres as the rain event peaked. A number of sites received record-breaking daily rainfall for the month.
Significant recorded rainfalls included:
- Karratha Aerodrome – 210.6 millimetres, 8 February – second-highest daily volume for any month (behind 212.4 millimetres, 10 January 2006)
- Perth Metro – 114.4 millimetres, 10 February – second-highest daily volume for any month since 1876 (behind 120.6 millimetres, 9 February 1992).
Between 7-12 February, Western Australia recorded six-day rainfall totals of 150-200 millimetres, exceeding the monthly average almost tenfold.
The February flood event affected much of the Kimberley, Pilbara, Midwest Gascoyne, Metropolitan, Wheatbelt, Goldfields-Esperance and Great Southern, causing widespread impact across the state. Significant damage was caused to road and bridge infrastructure, particularly around Esperance; agriculture was severely affected with major damage to vineyards in the Swan Valley, near Perth. Tragically, two fatalities were recorded in separate incidents of vehicles driving into floodwaters.
In anticipation of the flood event, the Western Australia Department of Fire and Emergency Services (DFES) Regions prepared Heightened Readiness and Risk Actions (HRRA). These resulted in the prepositioning of seven IMTs and four Natural Hazard strike teams, and provided supplementary staffing to Regional Operational Centres in the Kimberley, Pilbara, Great Southern, Goldfields Midlands and Metropolitan regions.
Operational Area Support Groups (OASGs) were also established pre-emptively. Agencies that participated in the OASGs included local governments, the Departments of Water, Health and Aboriginal Affairs, Main Roads Western Australia, the Bureau of Meteorology, Western Australia Police and utilities.
All 11 DFES Regions were involved in preparatory actions; all but one were actively involved in response. The response included the resupply of four remote communities and over ten air drops, as well as land-based support over a period of eight weeks.
The flooding event was an eligible disaster under the Western Australian Natural Disaster Relief and Recovery Arrangements; 91 of the 138 local governments in Western Australia were eligible to receive assistance.