Storm hazards in tree work: lightning

This page reports what the named codes, regulators and makers say. It is not training and does not teach the work. This page reports what the official source says. It is not legal advice: ask the office named here. It sets out what weather services and work sources publish about lightning. All pages were read on October 9, 2026. The courses that teach tree work are in the guides on chainsaw tickets and certifications by country. What lightning does to a tree is in the guide on lightning damage to trees, and what each code says about stopping work in weather is in climbing in wind, rain, cold and lightning.

Credit. Wording from the SafeWork NSW Tree works code of practice is adapted under the Creative Commons Attribution 4.0 licence, with sentences shortened and reworded. The weather services, OSHA and NOAA are described in our own words with links.

United States: National Weather Service and OSHA

The National Weather Service page Lightning safety tips says that on hearing thunder people move to a substantial building or an enclosed metal-topped vehicle with the windows up, and stay there at least 30 minutes after the last sound of thunder. Its last-resort list for people caught outside says not to shelter under an isolated tree.

The OSHA and NOAA fact sheet Lightning safety when working outdoors lists logging and lawn services and landscaping among worker activities at higher risk. It says lightning can strike up to 10 miles from any rainfall, and that when signs of an approaching thunderstorm appear workers do not begin a task they cannot quickly stop. It names hard-topped metal vehicles with the windows up as shelter if no building is near, with a wait of at least 30 minutes after the last thunder.

Australia, Canada, Ireland and New Zealand

The Bureau of Meteorology's blog post Severe thunderstorms: your questions answered, December 10, 2018, says every thunderstorm has lightning, so the Bureau does not warn for lightning and warns instead for storms likely to cause damage: hail of 2 cm or larger, gusts of 90 km/h or higher, flash flooding or tornadoes.

Environment and Climate Change Canada's weather impact guides, dated February 20, 2026, note that lightning can occur with any thunderstorm. Its thunderstorm guide lists damage to roofs, fences, soft shelters and trees at the moderate level and a risk of serious injury at the high level.

Met Eireann's weather warnings explanation gives a yellow thunderstorm warning for thunderstorms, lightning activity, heavy rainfall or hail, and an orange one for widespread thunderstorms or severe lightning activity. It advises being aware of lightning and not sheltering under an umbrella or a tree.

MetService's page About severe weather warnings and watches says a thunderstorm warning is issued when an active severe thunderstorm is detected and is always red. Its severe thunderstorm criteria are rain of 25 millimetres an hour or more, hail of 20 millimetres or more, gusts of 110 km/h or more, or a tornado rated F1 or above.

SafeWork NSW

In its Tree works code of practice, SafeWork NSW lists lightning among weather hazards, saying it poses a risk of injury or death especially during thunderstorms or near conductive materials, and says that in hazardous weather including lightning activity work should stop and be rescheduled.

How each source treats lightning

Source	Lightning in its warnings	Work wording
National Weather Service	Safety page	Shelter on thunder; 30 minutes after the last
Bureau of Meteorology	No separate warning	Not published
Environment and Climate Change Canada	Part of the thunderstorm guide	Not published
Met Eireann	Named in yellow and orange thunderstorm warnings	Not under a tree
MetService	No separate criterion	Not published
SafeWork NSW code	Not applicable	Work stops and is rescheduled