Heatwaves
What is a heatwave?
A heatwave is defined as a period of 3 days when the conditions are well above the average conditions for your location. The severity of the heatwave is dependent on your location. Kite uses 45 years of site-specific climate data to work out “what is average” for your site. It also looks at the weather for the past 30 days. If the heatwave is early in the season or is a sudden change from the last 30 days, the severity of the heatwave is increased.
Kite determines a heatwave using the same methodology as the Bureau of Meteorology, except Kite uses both Temperature and Humidity (BOM only looks at temperature) and is therefore more relevant to assessing the risk of heat stress.
The Heatwave Intensity is calculated once per day. The heatwave Intensity tells you what the environmental risks are. “How extreme are the weather conditions for my site compared to what is normal?”.
Because the heatwave intensity is based on the underlying principle that you are acclimatised to your location climate, additional measures should be considered for fly-in/fly-out workers for at least the first two weeks onsite.
It is also important to note that non-heatwave days can also have a heightened risk of a heat illness. Under conditions when the body has limited cooling capacity for any reason (such as extreme humidity and/or temperature, no air movement or due to protective clothing), the body can overheat in under an hour for moderate activity. Therefore it is important to look at all risk factors to determine the risk of a heat illness. Kite Thermal Risk Assessment can do this for you.
Kite provides a 14-day outlook of heatwaves (and rain). The weather conditions that generally result in a heatwave are well forecast 7-10 days out, the severity or exact day of the peak may vary as the event becomes nearer.
Where can I find it?
The Heatwave Warning level (see explanation below) is presented on the Outlook dashboard. It is also presented on the daily cards on the standard heat risk dashboard.
Example Outlook Dashboard
What does it mean?
A heatwave is defined by the amount of excess heat over a 3 day period. If the excess heat is above the top 5% (about the hottest 20 days per year) it is categorised as a heatwave. The intensity level of the heatwave (HWI) is defined in the table below.
The intensity for both temperature only and temperature and humidity heatwaves are presented. The risk level is determined by the maximum intensity of either type of heatwave.
Heatwave Warning | Heatwave Intensity (HWI) | Description | Recommended Actions |
|---|---|---|---|
No alert | 0 | No heatwave present | Basic heat safety and planning. |
Low | 0 - 0.25 | Low-intensity heatwave identified that could represent the start or the end of a higher-intensity heatwave | Basic heat safety and planning. |
Moderate | 0.25 - 1 | Moderate intensity heatwave that may result in heightened heat risk for higher-risk workers. | Implement precautions and heighten awareness. |
High | 1 - 3 | High level heatwave that may result in heightened heat risk for higher-risk to medium-risk workers. | Implement additional precautions to protect workers. |
Extreme | >3 | Extreme heatwave that is likely to result in heightened heat risk for all workers. | Consider the need to work or implement even more aggressive protective measures. |