Preparing for Severe Weather

It’s been a steamy afternoon on the jobsite, and the heat and humidity have energy levels trending low and tempers running a bit higher than normal. The sky to the southwest has been darkening for several minutes, and there’s an eerie feeling in the air. Suddenly, everyone’s attention is capture by the loud wail of a nearby storm siren, and half a dozen workers look at you for instructions. What do you tell them?

Ask the workers on a typical jobsite about the hazards they face on a daily basis, and few (if any) will put severe weather near the top of the list. But in most parts of the U.S., severe weather conditions happen every year. For those who live in one of the nation’s “tornado alleys,” powerful thunderstorms are a regular element of spring and summer weather. Other parts of the country may contend with hurricanes, flooding, or other weather extremes.

No place is completely safe from nature’s fury. That’s true for indoor workplaces, but it’s an even greater concern on outdoor jobsites. That’s why steps for dealing with severe weather situations are a critical part of any safety plan. While you can’t predict extreme weather with any degree of accuracy, you can protect your team by preparing for the problems it creates.

What are your potential hazards?

Safety plans identify the potential hazards that may be encountered on the worksite, and that’s the first step in preparing for severe weather. You need to identify the types of weather events that may occur at your jobsite. That may include severe thunderstorms and tornados. Or, if your site is in a lowland area adjacent to a creek, flash flooding may be a prime concern.

Simply saying that you may face a severe thunderstorm isn’t enough. You need to drill down to the specific hazards associated with thunderstorms. For example, a thunderstorm becomes “severe” when it produces hail that’s at least three-quarters of an inch in diameter, winds that gust over 57.5 miles per hour, or tornados.

You already know that tornados are dangerous, but did you realize that severe thunderstorm winds actually create more damage each year? Those winds can reach speeds of as high as 100 miles per hour, damaging structures and turning ordinary debris into dangerous projectiles.

A half-inch hailstone falls at an estimated nine meters per second. That’s just over 20 miles per hour, so getting hit would be a little painful. Baseball-size hail travels at even higher speeds, falling at rates that can go over 100 miles per hour — and a baseball is softer than a solid ball of ice.

Lightning is a hazard that many people underestimate, even though the nation’s skies are lit by nearly 25 million flashes every year. While only about 50 people die from lightning strikes in an average year, hundreds of others are injured, and outdoor workers are at particularly high risk.

What will you do when weather threatens?

Once you’ve identified the potential hazards, you need to determine the actions that will be taken if each occurs. Your plan should designate the individuals who will be responsible for making decisions regarding severe weather, as well as how they will be informed of threatening situations.

Your plan should include some type of heightened monitoring when severe weather has been forecast. One way would be through the use of special weather radios that sound an alarm when severe weather warnings are issued. It’s a good idea to use more than one method of notification in case one of the methods you choose fails. Remember that a weather “watch” is issued when conditions are favorable for severe weather to develop, while a “warning” is made when the particular type of weather is actually happening — such as when a tornado has been sighted.
Next, the plan should detail how you’ll convey the weather information to those on the jobsite, and the specific actions you’ll expect them to take. If they need to proceed to safer areas, be sure that those areas can accommodate all of the workers who may need to use them.

If you have employees out in the field or at remote sites, be sure to include a way to inform them and to verify that they received the information. A crew working at a remote site in a rural area may be especially vulnerable to weather-related hazards, and you may want to incorporate special training, so they know how to react.

Finally, verify the effectiveness of your plan by holding drills, just as you would hold fire drills or practice evacuations. A drill will confirm that your workers and supervisors know exactly what they’re supposed to do and where to go. It will also help you identify any improvements that you’ll need to make.

Pay special attention to lightning

Again, many people underestimate the dangers associated with lightning. One of the biggest misconceptions of lightning is that you’re only in danger when a storm is roaring overhead. Actually, lightning can strike at some distance from where rain is falling — even as far as 10 miles from the actual storm.

A good rule of thumb is that if you can hear thunder, you’re close enough to be struck by lightning. So on an outdoor worksite, if workers hear thunder, they should move to a safer location. In addition, if thunderstorms are in the area, workers should not begin tasks that they can’t stop performing on short notice. That way, if the weather suddenly worsens, they can stop working and immediately move to shelter. If safe indoor shelter is not available, sitting inside a metal-roofed vehicle is a good alternative, but it’s important to keep the windows closed.

As you’d expect, workers on tall objects such as towers and scaffolds are at higher risk of lightning strikes, as are those who work in wide open spaces. Working around conductive materials such as metal framing or piping increases the risk.

When someone is struck by lightning, co-workers may be afraid to offer assistance because they fear that they will also be shocked. However, it’s safe to touch someone who has been struck — and they will need immediate medical attention (in many cases, that may mean CPR). Even if the person seems to be okay, call 911 so they can be checked out by medical professionals.

About tornados and other winds

While most people are familiar with tornadoes and the damage they can cause, they’re not the only kind of dangerous windstorm. Besides straight-line winds, storms may contain sudden downbursts or microbursts, which can be just as damaging, but tend to cover a smaller area for a shorter time. Some strong thunderstorms are preceded by what are known as gust fronts, in which the wind suddenly switches and intensifies. Often, the air temperature drops significantly in a short period of time.

When workers are faced with a tornado or other severe wind event, they must take immediate steps to protect themselves. By the time a tornado is visible, it may be too late to take action. While the safest place to ride out such a storm is a basement or shelter, there may not be one at the jobsite. Mobile facilities, such as construction trailers, are generally not places for shelter.
If no safe shelter is available, workers should get into a vehicle and attempt to drive to a safer area. If the storm approaches and they are surrounded by flying debris, they should park and put their head below the level of the windows. If they can safely exit the car and there is an area that is much lower than the road, they can lie in that area. Whatever option they choose, they should protect their heads from debris.

After flooding occurs

Just because the water levels may be receding in the days following a flood, it doesn’t necessarily mean that a worksite is safe. Puddles and muddy areas may be deeper or more treacherous than they appear to be, and downed power lines may be present. It’s also possible that gas lines and other utilities may have been damaged, or that the water had come in contact with hazardous materials. Finally, floodwaters may drive venomous snakes and other animals into flooded buildings and other unfamiliar areas.

That’s why it’s so important that the flooding-related portion of your safety plan includes careful inspection and cleanup of jobsites before workers are allowed to resume their normal tasks. The storms may have passed, but that doesn’t mean the dangers have ended. By taking a comprehensive, step-by-step approach, you can minimize the chances that a severe weather event will turn into a disaster for your worksite.

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