While we are still to learn the full extent of the damage and economic disruption of Cyclone Debbie, we should be reasonably confident that any adverse economic impact, such as through lost crops, tourism, or disruption to coal mining and exports (see this ABC News report), is temporary, and the State economy will likely recover quickly from it, as it has from previous natural disasters. Indeed, it is expected that capital works during the reconstruction effort will provide a temporary stimulus to affected regional economies. This is what happened in particular after the 2010-11 natural disasters: the floods and Cyclone Yasi (see chart below).
Keep in mind that the State economy is frequently subjected to a wide range of shocks, such as changes in the exchange rate which affect tourism and exports, and changes to global commodity prices which affect mining investment and operational decisions. Natural disasters are another type of shock, which can have a large negative impact on gross state product (GSP) growth in one quarter, but typically do not have a long-lasting adverse impact on the economy. See my 2011 post on Recovery from natural disasters, which quotes John Stuart Mill on the long-observed phenomenon of rapid recovery from natural disasters.
The State Budget will no doubt take a significant hit from Cyclone Debbie, as coal production and royalties may be temporarily lower and as the Government needs to undertake emergency disaster relief measures. I expect our hard-working Queensland Treasury officials, already in the middle of State Budget preparations, will be spending even longer hours in the “Tower of Power” at 1 William St, working out the impact of Debbie on the Budget bottom line.