Storm hazards in tree work: wind

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 publish about wind and what two work sources say about it. 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 each code says about stopping work in weather is in the guide on climbing in wind, rain, cold and lightning, and the wider storm picture is in storm work.

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 and Scottish Forestry are described in our own words with links.

United States: National Weather Service

The National Weather Service safety page on wind says high winds can come with a severe thunderstorm, a strong weather system, or flow down a mountain. It says that when winds are sustained at 40 to 50 mph isolated wind damage is possible, that widespread significant damage can occur at higher speeds, and that straight line winds in strong thunderstorms can exceed 100 mph.

Canada: Environment and Climate Change Canada

The department's weather impact guides, dated February 20, 2026, replace the former criteria for public weather alerts and describe each hazard at three impact levels: moderate, high and extreme. The wind guide gives no wind speeds. At the moderate level it lists larger tree branches broken and a risk of injury from flying or falling debris, at the high level small to medium trees snapped, and at the extreme level significant damage to trees including orchards and parks.

Ireland: Met Eireann

Met Eireann's page Weather warnings explanation sets wind figures by colour. Yellow is widespread 10 minute mean speeds of 55 to 65 km/h and gusts of 90 to 110 km/h. Orange is mean speeds of 65 to 80 km/h and gusts of 110 to 130 km/h. Red is mean speeds above 80 km/h and gusts above 130 km/h. The page calls the figures strong guidelines and says impact varies with place and the weather before. It says gusts can damage or fell trees even when the speeds are not particularly strong where trees or structures were weakened by an earlier storm, and that trees are more vulnerable to strong winds when in leaf.

Australia: Bureau of Meteorology

A Bureau of Meteorology blog post of December 10, 2018, Severe thunderstorms: your questions answered, says a thunderstorm is classed as severe when it produces wind gusts of 90 km/h or higher, which can cause damage to vegetation and buildings, and that gusts at or above 125 km/h add the words destructive wind gusts to the warning.

Work sources: Scottish Forestry and SafeWork NSW

Scottish Forestry's page Managing storm damaged trees says extreme wind exceeding 90 mph can have devastating effects, and asks owners to prepare a windblow contingency plan. The SafeWork NSW Tree works code of practice says that during hazardous weather such as strong winds work should stop and be rescheduled. Among hazards near electric lines it lists wind blowing branches against the lines and high winds causing loss of control while lowering materials.

Side by side

Source	Wind figure published	Wording about trees
National Weather Service	Sustained 40 to 50 mph: isolated damage	None on the page
Environment and Climate Change Canada	Not published	Branches broken, then trees snapped, then trees destroyed
Met Eireann	Yellow gusts 90 to 110 km/h	Trees more vulnerable in leaf
Bureau of Meteorology	Severe thunderstorm gusts 90 km/h	Damage to vegetation
Scottish Forestry	Above 90 mph: devastating	Windblow plan