As we've seen with the devastating northern NSW and Queensland floods – and costliest ever - earlier this year, a one-in-1,000-year flood doesn't only occur every millennium.

Despite the minuscule 0.1% chance of that type of flood happening in any location any year, it can occur in two consecutive years, says Weatherzone. That's what the town of Lismore has endured already this year.

Experience can be an expensive teacher, so what can we learn about the risks of these floods and how to protect our assets?

Having a flood action plan can reduce damage to your business by an estimated 80%, according to the Business FloodSafe Toolkit and Plan. It adds the plan needn't be expensive or time-consuming.

Why unpredictable weather is becoming more common

For those interested in finding out more about our changing climate, Carbon Brief has mapped how climate change impacts extreme weather worldwide. Based on scientific studies, the site gives a detailed analysis of climate change events. Select pre-2011, for example, and you'll gauge the change over the past decade. Impacts listed include:

• Atmospheric, storms

• Rain, flooding, river floor, storms, cold, snow and ice

• Sunshine, heat, wildfire, drought

• Oceans, coral bleaching

• Ecosystem function.

From the ground up: Establishing flood-proof buildings

Follow your local council for updates to flood management plans because new developments can change the hydrology – and, therefore, nature of floods – in your area.

That's where modern technology can help. You can build new premises or retrofit an existing one to minimise flood damage and boost its flood mitigation capability. Best practices include building walls without cavities, so water can't be trapped and thereby encourage mould. Have separate electrical circuits upstairs from downstairs, so if the ground level gets flooded and switches off, you'll still have power upstairs. Other ways to avoid trapping water include having louvres come down to the ground and setting door sills flush with the floor. Look into geopolymer concrete, too.

Simple methods you can use to flood-proof your business

Simple measures can make a difference to help flood-proof homes and businesses, including:

• Investigate automatic or manual flood barriers or a flood gate on a door to stop major flooding

• Install temporary flood barriers around essential equipment

• Raise the electrical switch to prevent water from penetrating the switch and, if you can retrofit electrical sockets, raise fuse boxes to at least 1.5m above floor level

• Keep computer and office equipment off the floor

• Plant small-scale thirsty rain gardens for water to naturally drain through the soil

• Raise damp proof courses and cover ventilation bricks

• Lay flooring tiles rather than wall-to-wall carpet

• Use watertight materials such as stainless steel, plastic, or solid water, not chipboard for internal fittings in kitchens, bathrooms, etc.

Create a business flood safe plan and save it online as well as in hard copy. Display a copy at your business premises, store one in your emergency kit and keep another printed version off site. Use this guide to get you started, and this Business Queensland flood preparation checklist for insights. Ensure your plan covers:

• Understanding your problem – the potential impacts on your business and priorities to manage and overcome them

• Setting out the actions, what triggers them and who to contact in the event of a flood

• Building in regular training and communication with staff about the plan

• How you'll review and update your plan and who has responsibility for doing so.

Prompts to review your plan include after flooding, training, changes to employees' responsibilities, business activities, building design, layout and in the river catchment.

Does my business insurance cover floods?

Know the current definition of a flood that insurers use in Australia, i.e.:

"…the covering of normally dry land by water that has escaped or been released from the normal confines of (a) any lake, river, creek, or other natural watercourse, whether or not altered or modified, or (b) any reservoir, canal or dam."

Only some insurers offer full flood cover for businesses. As your broker, we can help you demystify the policy fine print to ensure your business is appropriately covered. We can help you bolster your risk management strategy so you have peace of mind you're doing all you can to protect your business.