When should you act?
The 30-30 Rule
A widely accepted rule indicates that you should seek a safe location whenever the flash-to-thunder time (Flash to Bang) interval is less than 30 seconds or 10 km distance to the lightning activity.
The “30–30 Rule” states that when you see lightning, count the time until you hear the associated thunder, and if this time delay is 30 seconds or less, go immediately to a safe location as described below.
If you cannot see the lightning, just hearing the thunder means you are most likely to already be within striking range, and it is time to seek whatever appropriate shelter is available.
The “30–30 Rule” is best suited for existing thunderstorms moving into the area. However, it cannot predict nor protect against a first lightning strike. Thunderstorms can develop overhead without preceding thunder in the distance. Be alert to changes in sky conditions portending thunderstorm development directly overhead.
After the storm conditions have apparently dissipated or moved on, wait a further 30 minutes, after hearing the last thunder before leaving the safe area location. Should thunder be heard within this period, restart the 30-minute count.
Where should you go?
When lightning threatens, individuals should promptly secure livestock and seek safe shelter.
Safe shelters include:
- Fully enclosed metal caravans and hard-topped vehicles with windows up
- Substantial brick/concrete buildings, well earthed by plumbing and electrical connections.
The Association has sought the Trustees’ advice whether any other buildings on the Showground have been adequately protected against lightning strike in accordance with the relevant Australian Standard. Pending that advice, only the toilet blocks can currently be considered to offer some safety. However, other buildings at the Showground may offer protection against hazards from hail and strong winds, which often accompany thunderstorms.
Unsafe shelter areas and activities include:
- tents, insubstantial, open-sided and unearthed structures.
- all outdoor metal objects, like power poles, fences and gates, high mast light poles, fairground and electrical equipment.
- solitary trees.
- open water.
- open fields and other outdoor spaces.
- high ground.
- riding in open topped vehicles, or on horses.
If you feel your hair standing on end, and/or hear "crackling noises," you are in lightning's electric field. If caught outside during close lightning activity, immediately remove metal objects (including baseball cap, jewellery, belts, car keys etc.), place your feet together, duck your head, and crouch down low with hands on knees. Avoid close proximity to other individuals, livestock etc.