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Severe thunderstorms
Large hail, damaging wind, frequent lightning. Rare in the UK but it happens.
Context
The UK averages roughly 200–300 thunderstorm days a year across the country, but only a handful of those produce *severe* convection — hail above 20 mm, wind gusts above 60 mph from a thunderstorm core, or tornadoes. When the Met Office issues a thunderstorm warning, take it seriously even if you've never seen one fire in your area.
When this matters
Met Office yellow / amber thunderstorm warning is active, or chaseit's outlook flips to SLGT / ENH / MDT / HIGH for your region.
Before
- Charge phones and power banks — lightning often takes down rural mains for hours.
- Bring outdoor furniture, trampolines, and parasols inside. Trampolines launch in 50+ mph gusts.
- Park vehicles undercover if possible. Hail above 20 mm dents body panels and cracks windscreens.
- Identify your sturdy shelter — an indoor room away from windows on the lowest floor of a permanent building.
- Don't rely on caravan, tent, or conservatory for shelter from severe convection.
During
- Get indoors when you hear thunder. The 30/30 rule: if the gap between flash and bang is less than 30 seconds, you're within strike range; stay inside until 30 minutes after the last thunder.
- Stay off corded phones, baths, and anything plumbed in — lightning travels through wiring and pipework.
- Don't shelter under isolated trees — trees are the most common UK strike fatality vector.
- If caught in the open with no shelter: crouch low, feet together, head down, hands off the ground. Don't lie flat — that increases the area of ground current you're exposed to.
- In a vehicle, stay inside with the windows up — the metal cage diverts strike to the ground. Avoid touching internal metal.
After
- Don't approach downed power lines. Call 105 (UK national power outage line) or 999 if anyone is hurt.
- Check on neighbours — particularly elderly or anyone living alone who may be without power.
- Photograph hail damage to vehicles and property before moving anything — insurance claims are stronger with timestamped evidence.
- If you saw severe weather first-hand, log a report on chaseit so it gets matched to the verification engine.
UK specifics — numbers, sources
- Met Office issues thunderstorm warnings via the National Severe Weather Warning Service (NSWWS). Yellow = be aware, amber = be prepared, red = take action.
- Lightning fatalities in the UK average 2–3 per year, the majority outdoors and at least 50% under or near trees.
- TORRO (the Tornado and Storm Research Organisation) is the volunteer body that catalogues UK severe convective events. Member reports on chaseit can be cross-referenced into the TORRO database.
Watch the data
Live chaseit feeds relevant to this hazard:
General guidance. Your specific circumstances may vary — follow the Met Office, Environment Agency / SEPA / NRW, your local council, and emergency services for situation-specific direction. See the code of conduct for chasers in the field.