Menu Close

Inclement weather

What is inclement weather? There are weather conditions that can create serious danger on a construction site. They include: severe weather storms, electrical storms especially in Johannesburg, heavy rain, as well as ice early in the morning and strong winds.

Weather conditions can change quickly while on site. A plumber may be so focused on work, that they don’t notice the roiling clouds coming in ahead of a severe weather storm. Severe weather can create a hazardous working environment, whether wind, lightning storms, rain or heat.


High winds can cause serious injury and damage, when combined with unstable structures such as working on a roof, ladder, scaffold or any temporary structure. On some sites, there are wind meter readings which can be checked periodically as to its safety factor – which may be about 30 kilometers an hour. Often there are cranes on site – and if the cranes can’t work nor can the people.

There should be warnings: normally the principal contractor would give an instruction or a siren would go off, indicating an incoming storm; there may be lightning detectors; and a wind meter speed reading. These would alert management as to whether it was safe to work at heights or not. Sometimes, the danger isn’t visible: you cannot see wind, only its effects. When commencing to climb a ladder, one may not see the wind or its danger. By the time a worker gets to the top there is no protection. While wind may not affect us on the ground, higher up there are fewer barriers to stop the wind hitting the person, equipment or materials in its path. It is powerful enough to lift up loads off a crane and crash them to the ground. Blown materials can strike workers and cause them to lose their footing, or worse.

Insurance has force majeure measures in place so that when a huge storm breaks the insurers will pay for damages caused – as with the flooding in KZN.

But on top of that, safety precautions should be put in place. The best thing a contractor can ever do is to ‘be prepared’. Even where a weather forecast gives the all-clear, they still need to be prepared with a back-up plan and regularly update themselves with weather forecasts even in the case of a small change. Always be prepared for the worst case scenario.

If the weather app gives a 60% chance of rain late in the afternoon, with wind speeds of about 20 kilometers an hour – those odds may seem fine. Yet events can rapidly change, blowing away a full day’s work. So be cautious, perhaps take a look and see if there is work that could be done indoors in the afternoon, or any work at height that could rather be done in the morning or earlier in the afternoon, before the late-afternoon possibility of high wind, rain or a storm. Even if it eventually doesn’t rain, at least you were prepared for it and the work schedule was not disrupted. It does take preparation and coordination between contractors on site: often jobs have to be done in a specific order, and one contractor may want certain things done at a certain time.

What must be done in the event of high winds and you are not allowed to work?

Primarily, all work at height and lifting has to cease. Work must be re-assigned as discussed if there is any potential to reassign certain dangerous work before the inclement weather actually happens. When the weather does strike workers can then be automatically reassigned to safer work. Any work materials must be strapped down before going indoors, storing them properly out of the wind and then secure all structures.

Following the cessation of the inclement weather, in this case high wind, all scaffolding and temporary works must be reinspected – workers may not climb up a scaffold without them having been inspected by the competent person. In this instance, the competent person will be the scaffolding inspector and scaffolding supervisor together. In addition, any step ladders that were setup have to tightly secured before the weather and reinspected after by the ladder inspector, as well as anything that was temporary-placed, including stacks and storage areas outside, as they could have been affected by the wind.

Electric storms

High winds often bring storms, including electric storms with lightning which can cause serious injuries and property damage. No work should take place outside during a lightning storm, especially not any working at heights. Many people feel that because it’s safe to work inside, they can continue on as normal. However, if work is to being done inside a building, there may still be lightning risks. Electrocution can occur due to incorrect cabling, and poorly insulated or poorly grounded tools. Perform a proper site inspection to determine whether to keep away from areas where there is a possibility of outside lightning impacting the inside.

While working inside during a lightning storm, workers should determine what tools are allowed and what are not allowed to be used. If a worker doesn’t know, they should speak to the safety officer or principal contractor, who are required to have a severe weather plan in place. This may include lightning detectors, wind speed meters, or a procedure in place on what to do during severe weather. Workers on site should know the emergency procedures if the case of an incident or accident – but do they know what the severe weather plan is for the site or their contract?

A project might not be on a construction site but rather in corporate or retail offices, which might not be included in a severe weather plan. Such a plan can still be included in the method statement risk assessment, or health and safety policy. Contractors should be prepared for things like this because when it happens, it happens very quickly with no time to prepare. The risks are that employees may experience electrocution, and fires can break out during lightning storms.

Therefore, all construction sites must have proper lightning detectors and a policy to raise awareness when the storm season approaches. Plans must be regularly checked and tested to ensure they work properly. If workers hear the lightning alarm, they must be trained to immediately stop work and adhere to the lightning protection procedure.

The emergency coordinator of the site must ensure all workers are safely indoors until it is safe to continue working. During an induction procedure, each worker should learn who is their safety officer, their health and safety representative, their first aider, their firefighter and their emergency controller. They should keep this information readily available, even on their person or mobile phone in case of emergency.


Storms bring rain which, apart from itself bringing hazards can cause flooding, collapsing of excavations and slippery, muddy surfaces. Any excavation must be inspected after rain to see that it is still safe. Excavations can collapse because of the soft soil due to the rain, or slippery surfaces in and around it. The excavation supervisor and inspector will determine whether it is safe to continue to work or not. Work may need to stop completely until the hazard passes or until there is no water in the excavation. It may need to be pumped out first and dried before work resumes.

If there is no other work, workers must leave site. Where there is other work, preparation based on weather forecasts would permit rescheduling work accordingly to work on the excavation while its dry and other work during the rains.

Contractors should make sure they have a weather app to check if severe weather is going to affect work. Forecasts can give five days advance warning, some even seven to 14 days.

Working at heights, excavations or trenching is affected by weather, and foreknowledge means contractors can get done on Monday or Tuesday what might be weather affected on Wednesday or Thursday. Clients will typically agree to rescheduling because they also have an interest in work safety. Such fore planning immensely improves not just the work ethic in the minds of clients, but shows to the client the contractor takes initiative from an occupational health and safety perspective.

After a storm and rain, all scaffolding and temporary structures must be re-inspected and made safe. Excavations must be inspected, and potentially closed off, if they are unsafe to work in, especially if they are flooded. If somebody falls in, it could be a possible drowning. Even if the site is temporarily abandoned, there may still be risks and hazards if somebody else were to get onto that site and did not observe the excavation site was closed.

If barricading was not sufficient to stop such people from falling in, there could be a substantial liability for the contractor. Once the rain has stopped and work continues, the effects of that rain will continue to be a hazard on site. Therefore, contractors should not automatically continue working without checking for slippery or muddy environments, and make sure to re-inspect all working areas before resuming work. For instance, a hazard may be extension cords left lying in water if not put away before the rain.


Heatstroke is a condition caused by one’s body overheating usually as a result of prolonged exposure to or physical exertion in high temperatures. The most serious form of heatstroke or heat injury can occur if body temperature rises to 40 degrees Celsius or higher. The condition is most common in the summer months.

Heatstroke generally requires emergency treatment because if it goes untreated it can rapidly damage the brain, heart, kidneys and muscles. The damage will worsen the longer the treatment is delayed, increasing the risk of serious complications, or even death. Even if one is wearing PPE on site such as hard hats, reflective vests, safety boots and overalls, these all make people sweat quite a lot when working outside on a steel structure on scaffolding performing laborious work in high temperatures. It’s quite easy for people’s bodies to reach temperatures of 40 degrees Celsius or higher because of the physical exertion in heat.

Nor is it only persons on the outside of buildings, on scaffolding or heights that can be affected by heatstroke – it can also happen to a person indoors if there is no ventilation, or no circulation of air to keep that person cool.

By Eamonn Ryan, based on a Tech Talk by Chris Coetzee on weather risks

Leave a Reply

Your email address will not be published. Required fields are marked *