Last Thursday Victorians were told by the Bureau of Meteorology (BOM) to expect “absolutely massive” rainfall, we were moving into "uncharted territory". Asked to rate the storms out of 10 a BOM spokesperson said: “I’ll take the punt and say it’s a 10 for Victoria.”
What eventuated was significant in terms of rainfall totals in many areas, particularly the north-east. Records were broken. However, the rainfall totals in Melbourne were not as significant and importantly the consequences were relatively minor from a state perspective.
Warnings are inherently difficult for emergency agencies to communicate effectively. 7.4 million text message alerts were sent out on Friday night, events were cancelled, people stayed out of the city and some restaurants closed. Overly conservative warnings can lead to a loss of trust in an agency, which in turn can lead to warnings not being heeded in the future. Economic loss from unnecessary precaution and preparation can also be significant. On the flip side understated warnings can also lead to a lack of trust and significant consequences for those subsequently unprepared for a disaster.
So what can emergency agencies do to ensure their warnings are communicated effectively and at the right level? The Australian Attorney-General's Department developed Emergency warnings—choosing your words as a reference document on how to construct the wording of emergency warning messages. Of the 10 guiding principles in this document, a couple resonate in relation to the BOM's warnings:
- Accuracy is important
- Be as specific as possible
The BOM overemphasised the worst-case scenario as a blanket warning across the state. While the BOM was accurate in terms of rainfall they were not accurate in terms of timing, location and intensity, nor consequence. This is understandable as there is always some uncertainty in such predictions. However, the BOM probably could have done more make this uncertainty clear.
The Bureau of Meteorology should not have called the weekend’s big wet a “10 out of 10” weather event, Victoria’s emergency commissioner has said. “I’m not saying the bureau has got it wrong but ‘10 out of 10’ was overused,” Craig Lapsley told ABC Radio on Monday. “I think that set a bar that was right up there.”